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750 Breva Engine noise

Printed From: guzziriders.org - moto guzzi forum
Category: Technical
Forum Name: Small Blocks
Forum Description: V35 up to V750 including Breva750, V7, V9 and new V85.
URL: http://www.guzziriders.org/forum_posts.asp?TID=9404
Printed Date: 19 Mar 2024 at 11:18
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Topic: 750 Breva Engine noise
Posted By: NevilleG
Subject: 750 Breva Engine noise
Date Posted: 07 Nov 2018 at 14:20
I'm new to this forum, but not new to Guzzi bikes having owned both a 750S3 and a California before my current Breva 750, but the engine on this one emits a peculiar deep knocking noise when hot and with the clutch pulled in, which wasn't present on the other models.
I bought this bike in June this year to replace an identical one that I had bought in May, but as that first one had a faulty clutch thrust bearing, it was bought back by the seller. However, that one also made the same noise, but it was much louder than this second one.
It's not there when the engine is cold, only when fully warmed up.
Does anyone know what might be causing the noise, assuming it is common to all the models that use this engine - Nevada's, V7's etc.
I have taken a video of the noise made by the first bike, where it was more pronounced, which I could send to anyone for a diagnosis if they would like to send me a Private Message.
Many thanks for your help. Nev.


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V7II Stone



Replies:
Posted By: Mr Grumpy
Date Posted: 07 Nov 2018 at 14:53
Mine does it too - thought it was 'normal' along with all the other clattering that goes on.


Posted By: nab301
Date Posted: 07 Nov 2018 at 19:37
My B750   can  get  a  bit noisy  when very hot  ( pulling the clutch ) I wouldn't describe it as a knock though ...   maybe more of a rattle ?




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Nigel
Keep smiling , it makes people wonder what you've been up to!
'19 CB125F,

'18 DL250 SUZUKI V STROM,'99 Bmw R1100S, '03Bullet 65 500, '93 MZ301 Saxon fun (offroad)


Posted By: NevilleG
Date Posted: 08 Nov 2018 at 11:20
Originally posted by nab301 nab301 wrote:

My B750   can  get  a  bit noisy  when very hot  ( pulling the clutch ) I wouldn't describe it as a knock though ...   maybe more of a rattle ?





No, mine is definitely a deep persistent knock, much like a knackered main bearing does. If yours is a rattle, that must be something else. Nev.

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V7II Stone


Posted By: Brian UK
Date Posted: 08 Nov 2018 at 14:50
I assume this is only on tickover?

The V twin does present problems with uneven firing strokes particularly at tickover, and this can cause a deep knocking sound from the gearbox.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 09 Nov 2018 at 13:18
Originally posted by Brian UK Brian UK wrote:

I assume this is only on tickover?

The V twin does present problems with uneven firing strokes particularly at tickover, and this can cause a deep knocking sound from the gearbox.


   I know the gearbox is prone to rattle a lot when hot and an uneven tickover makes it worse, but pulling the clutch in disengages the gearbox and stops the rotation and any rattle. By careful throttle valve and air-bypass balancing, I have got my tickover very even, so that is now pretty minimal.
   This deep knocking noise definitely comes from the engine and seems more prevalent at the front.
   My guess is that it might be crankshaft end-float, after the load of the gearbox is removed, but I would be interested to hear if it is common to all 750 models and years. My Breva is a 2007 model.
     Nev.

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V7II Stone


Posted By: Bugsy
Date Posted: 09 Nov 2018 at 13:30
Nev - my 2007 Breva 750 does not make any worrying noises (so I hope this commment doesn't hex it!) and I run old British bikes so I know all about rattles and knocking. However my Breva has only 5,600 miles and some of these bikes do huge mileages with good regular maintenance. So, if I may ask, has your bike done a lot of miles and has it had regular oil changes do you know?


Posted By: Brian UK
Date Posted: 09 Nov 2018 at 14:07
Not heard of any probems on the B750 in that area. Some later V7s had a problem with crankshaft endfloat but that was much later on.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 11 Nov 2018 at 12:03
Originally posted by Bugsy Bugsy wrote:

Nev - my 2007 Breva 750 does not make any worrying noises (so I hope this commment doesn't hex it!) and I run old British bikes so I know all about rattles and knocking. However my Breva has only 5,600 miles and some of these bikes do huge mileages with good regular maintenance. So, if I may ask, has your bike done a lot of miles and has it had regular oil changes do you know?


Hi Ron,
       The Breva I have now has done arround 17000 miles and the one that I had before that, where the noise was more pronounced, had done 25000.
This one has been very carefully maintained by the previous owner and he had put records of the oil changes etc. in with the handbook.
I'm pretty confident that it not a big problem and she will do many more miles without any further issues, especially as both bikes had this noise and other people have it on their bikes to.   However, I would still like to know how common it is and, moreover, if anyone knows what causes it.
Having had an assortment of bikes since 1954 dating from my first 1928 Ariel 500, I'm also very familiar with the assortment of engine noises that come with them, but I can't put my finger on what might be causing this one, particularly as it wasn't present on my similarly designed previous Guzzi's
    Thanks for all your contributions so far. Nev.

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V7II Stone


Posted By: rapheal
Date Posted: 14 Nov 2018 at 23:07
check that the exhaust system is secure, the heat shields can work loose and rattle, as can the silencer exhaust pipe joints
mines 15 years old now, if it stops rattling I start to worry !!



Posted By: NevilleG
Date Posted: 15 Nov 2018 at 10:01
Originally posted by rapheal rapheal wrote:

check that the exhaust system is secure, the heat shields can work loose and rattle, as can the silencer exhaust pipe joints
mines 15 years old now, if it stops rattling I start to worry !!



Hi Rapheal.
          I am aware that the two heat shields on the silencers come loose and rattle, having tightened them up twice already, as well as all the other joints.
    Perhaps I should make it clear that this noise is a KNOCK, you know, "DONK_DONK_DONK," consistent with each firing stroke, not a RATTLE.
    The noise is coming from low down at the front of the engine and, I repeat, is only there when the engine is HOT with THE CLUTCH IS PULLED IN and is most noticeable at tickover !
   In my experience, having owned two previous ones, Guzzi engines are normally extremely quiet mechanically, in particular my California with its hydraulic tappets, but the 750S3 was almost as quiet. The gearbox's were another matter !!
   Thanks anyway. Nev.

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V7II Stone


Posted By: Bugsy
Date Posted: 15 Nov 2018 at 14:32
It is tempting to suggest that normal riding involves the clutch being engaged (out rather than pulled in) and well above tickover. If the bike is OK under those riding conditions then is there much wrong? On most bikes I have known there have been a different set of noises when ticking over, clutch pulled and in neutral when compared with riding along.

None of this is an answer, I know. Have you tried the stethoscope test or perhaps the long screwdriver held to crankcase and ear, to gain a localised sound impression?


Posted By: NevilleG
Date Posted: 16 Nov 2018 at 10:29
Originally posted by Bugsy Bugsy wrote:

It is tempting to suggest that normal riding involves the clutch being engaged (out rather than pulled in) and well above tickover. If the bike is OK under those riding conditions then is there much wrong? On most bikes I have known there have been a different set of noises when ticking over, clutch pulled and in neutral when compared with riding along.

None of this is an answer, I know. Have you tried the stethoscope test or perhaps the long screwdriver held to crankcase and ear, to gain a localised sound impression?


Hi Bugsy.
      As I said in one of my previous replies, I am more curious to know what causes it and if it is common to all the V7 models, than worried about it.
   One person has said his bike also makes the noise, but I was hoping there might be some Guzzi technician out there that could a) Tell me what causes it and B) Tell me if it is a problem that will need attention in the long term.
     I have tried to pin-point it with the screwdriver in the ear technique, but it seems to transmit throughout the crankcase, probably because it is a low frequency.
     You sound like someone who is well experienced with motorcycle mechanics and if you would like to send me a Private Message containing your email address, I can send you the two videos that I made of the noise.   Nev.

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V7II Stone


Posted By: Brian UK
Date Posted: 16 Nov 2018 at 10:49
There was a crankshaft thrust bearing problem on a few of the later v7 models, but never heard of any recurring problem on the B750.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: Vegas Pete
Date Posted: 16 Nov 2018 at 17:11
I have a 2010 V7c that makes a knocking noise with the clutch pulled in at idle.  At first I thought it sounded like excessive crankshaft end float, based on previous experience with air cooled VWs, but l finally came to the conclusion that it was the clutch disc banging back and forth on the hub splines.  The crank does a lot of speeding up and slowing down between power strokes at idle on these things, and with the clutch disengaged the disc is free to float on the splines.  As soon as the clutch plate is pressed into contact with the flywheel and can no longer float, the sound stops.

That's my story and I'm sticking with it.

Vegas Pete.


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2010 V7 Classic, 2005 Ural Gearup, 1980 Yamaha DT175, 1973 Rokon RT-140, 1969 Rokon MkIII


Posted By: Mike H
Date Posted: 16 Nov 2018 at 23:16
Operating the clutch pushes the clutch pushrod forward and hence the pressure plate into the flywheel and in turn tries to push the crank forward. Noisy front bearing?




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"Chicken nuggets don't dance on a Tuesday."


Posted By: rapheal
Date Posted: 16 Nov 2018 at 23:58
might be worth checking that the engine mounting bolts are tight, that can exaggerate any noises
my bike thuds a bit under load, but its better when you rev the nuts of it
an Italian taught me that
this is a thing worth knowing
it makes it go faster
and it makes the dials whizz around which looks pretty


Posted By: NevilleG
Date Posted: 17 Nov 2018 at 10:33
Originally posted by Mike H Mike H wrote:

Operating the clutch pushes the clutch pushrod forward and hence the pressure plate into the flywheel and in turn tries to push the crank forward. Noisy front bearing?




Which bearing are you referring to Mike ?   Nev.

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V7II Stone


Posted By: Chris950s
Date Posted: 17 Nov 2018 at 13:11
It sounds like Mike is suggesting the front main bearing but I would be surprised if it is that on such a new bike. On the older bikes this is a plain bearing which any pressure from the clutch on the crankshaft would have little effect. I am not sure what type the main bearings are on the Breva but would be surprised if it is that. Have you worked out where the noise is coming from?

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Chris and Karen - Essex
2011 Stelvio NTX, 1974 950S (750S replica nearly rebuilt!), 1966 Triumph T100SS 58 years young this year!


Posted By: Dave P.
Date Posted: 17 Nov 2018 at 16:33
It could be worthwhile to check the oil pressure,at a dealers If you don't have the gear to do it at home.Any excess radial clearance between the front main bearing and the crank would result in a drop in oil pressure.I don't suppose this is the problem but it would be beneficial to know that all is well in that department and eliminate one possibility.

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TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.


Posted By: NevilleG
Date Posted: 26 Nov 2018 at 10:36
Originally posted by Dave P. Dave P. wrote:

It could be worthwhile to check the oil pressure,at a dealers If you don't have the gear to do it at home.Any excess radial clearance between the front main bearing and the crank would result in a drop in oil pressure.I don't suppose this is the problem but it would be beneficial to know that all is well in that department and eliminate one possibility.


If that was the problem Dave, I think it would still make the same noise without pulling the clutch lever in.
As Mike said, pulling the clutch pushes the operating rod onto a cup which in turn pushes the spring loaded pressure plate forwards, away from the friction plate. This action puts a load onto the end of the crankshaft, pressing it forward.
I can't see how that would, in itself, induce the noise, unless there was a large amount of end float in the crankshaft, sufficient to put the big-end bearings out of alignment with the con-rods. The main bearings are static, so can't be twisted out of line.   Is that likely ? If so, why does it only happen when the engine is hot ? Would the fact that the oil has thinned down allow the crankshaft to move a bit further forward ?

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V7II Stone


Posted By: Mike H
Date Posted: 26 Nov 2018 at 19:33
My BMW R80 once had an alternator brush spring jam - I was camping out Ledbury way at the time. Had the charge light coming and going. Went into Ledbury for food supplies during which I discovered if I pulled the clutch lever, light went out, when I let go, light came on. Thought it was weird but in hindsight I figured the crankshaft was moving forward when clutch was pulled, so the stuck brush touched a bit of the slip ring that was less worn, when released it went back again and the brush lost contact.

Strange but true.

NB: I fixed the brush on the site - had to smooth one side a bit so it could move again.





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"Chicken nuggets don't dance on a Tuesday."


Posted By: NevilleG
Date Posted: 27 Nov 2018 at 11:40
Originally posted by Mike H Mike H wrote:

My BMW R80 once had an alternator brush spring jam - I was camping out Ledbury way at the time. Had the charge light coming and going. Went into Ledbury for food supplies during which I discovered if I pulled the clutch lever, light went out, when I let go, light came on. Thought it was weird but in hindsight I figured the crankshaft was moving forward when clutch was pulled, so the stuck brush touched a bit of the slip ring that was less worn, when released it went back again and the brush lost contact.

Strange but true.

NB: I fixed the brush on the site - had to smooth one side a bit so it could move again.





Thanks Mike.   I am itching to get the covers off the alternator and check out the end float, if any, but at the moment I am resting my hands to try an ease a bout of "trigger finger", which is making some of the joints lock up.
My plan is get the bike warmed up so that the noise can be reproduced and, with the covers off, see if I can push the end of the crankshaft backwards, which may, or may not, stop it.   It may mean taking the alternator stator and rotor off out of the way, but that seems to be fairly straightforward and the engine should still run without them in place. I should also be able to feel any lateral movement and any vibration that's creating the noise being transmitted at the front end of the crankshaft.
As you are showing an interest, I would be happy to send you the two video's I took of this same noise on the first Breva I bought, if you send me a Private Message with your email address in it. Nev.

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V7II Stone


Posted By: theoneandonly
Date Posted: 27 Nov 2018 at 21:19
what grade of oil are you using ? 10/40 ? or 15/50 
i have recently seen a B7 run on 10/40 that had done the big end shells . 


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https://www.facebook.com/BaldricksWorkshop
http://baldricksworkshop.co.uk/

motorcycle slut, if it has wheels and an engine , i will ride it .


Posted By: NevilleG
Date Posted: 28 Nov 2018 at 12:44
Originally posted by theoneandonly theoneandonly wrote:

what grade of oil are you using ? 10/40 ? or 15/50 
i have recently seen a B7 run on 10/40 that had done the big end shells . 



As you may know, Guzzi recommend 5w-40 for this engine, so using 10w-40 shouldn't have been the cause of big-end failure. Probably some other reason.
I use 10w-60 Silkoline in mine.
One thing that can cause a bearing failure problem is that these engines only have a capacity of 1.8 litres, so frequent oil changes are absolutely vital.
There is a modification to fit a sump extender, which takes it up to about 3 litres. Gutzibits sell them.

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V7II Stone


Posted By: Mike H
Date Posted: 28 Nov 2018 at 20:06
Just a note, theoneandonly is No. 1 guru expert Guzzi mechanic, usually when he says summat, we prick up our ears. Big smile



NB: not to be confused with theoneandonlymin (different person)

HTH





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"Chicken nuggets don't dance on a Tuesday."


Posted By: Chris950s
Date Posted: 29 Nov 2018 at 09:50
Originally posted by Mike H Mike H wrote:

Just a note, theoneandonly is No. 1 guru expert Guzzi mechanic, usually when he says summat, we prick up our ears. Big smile
It would appear he has a fan club too  Wink


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Chris and Karen - Essex
2011 Stelvio NTX, 1974 950S (750S replica nearly rebuilt!), 1966 Triumph T100SS 58 years young this year!


Posted By: Brian UK
Date Posted: 29 Nov 2018 at 09:55
He would like to think so. Wink


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 04 Dec 2018 at 16:45
Originally posted by Mike H Mike H wrote:

Just a note, theoneandonly is No. 1 guru expert Guzzi mechanic, usually when he says summat, we prick up our ears. Big smile



NB: not to be confused with theoneandonlymin (different person)

HTH





Ah! Sorry, I didn't know that, so my reply was somewhat out of place !

On a brighter note, I couldn't wait any longer to check for any crankshaft end-float, so I took the alternator covers and stator off and found absolutely no movement at all, hot or cold. In fact I was surprised to find the engine very tight to turn over, almost like it was hardly run-in, despite it's 17000 odd miles, so I would be interested to hear if anybody else has noticed this.
When once I have put it all back together, I am going to put a torque wrench on the nut and take some readings of just how much effort is needed to move it, as I couldn't decide if it was easier when hot or cold. Obviously I had removed the spark plugs and had the clutch pulled in to remove any load from the gearbox.
After taking the front cover off (shearing a badly corroded bolt off in the process !!) I was disappointed to find quite a bit of surface rust on both the stator and rotor. Looking at the parts list, the cover is supposed to be secured by 5 bolts, but mine only had four bolts in the lower four holes and a plastic stud affair in the top hole. The cover had distorted slightly from engine heat, leaving a gap at the top, which had obvious let some water in. This plastic stud looked very original in its design and fit and there was no evidence of a bolt ever having been down the top (threaded) hole, so I'm confused as to whether this was how Guzzi built it, or if some previous owner had done it. Is anybody else's like this ??
    Nev.


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V7II Stone


Posted By: NevilleG
Date Posted: 04 Dec 2018 at 17:07
Further to my previous post, I forgot to mention that, with the engine hot and the noise evident, it was still there when the crankshaft was pushed backwards, so I am now fairly certain that it isn't an end-float issue.
Using the "screwdriver in the ear" listening technique, the noise was very evident as being transmitted from the crankshaft, so still needs more investigation.
One thing I haven't checked is if the noise disappears above tick-over revs, if it does, then the tight engine/hot oil/lower oil pressure/no load on the engine combination, might be causing bearing knock ? Dunno ! Nev.


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V7II Stone


Posted By: NevilleG
Date Posted: 11 Dec 2018 at 15:32
In my previous post, I mentioned that the engine seemed very tight to turn over, but at that time I had the clutch lever pulled in and tied back to the handlebar, but I have now carried out a few more checks, with the lever both pulled in and released and with the engine both hot and cold.
Below are the torque readings required to turn the engine over with the plugs removed as well as the alternator's stator, as the magnetic pull from the rotor is remarkably significant.
ENGINE COLD, clutch released = 8nm.
ENGINE COLD, clutch pulled in = 18nm

ENGINE HOT, clutch released = 8nm
ENGINE HOT, clutch pulled in = 22nm

You can see that the readings with the clutch released are the same (8nm) regardless of the engine temperature, so the piston expansion when hot has no effect. However, as soon as the clutch lever is pulled in, applying a load to the end of the crankshaft, the effort required is more than doubled and, not only that, but the effort needed is slightly more when the engine is hot.

On each side of the rear main bearing is a thrust washer to locate the crankshaft laterally and control end-float, and each thrust washer appears to be made up of two semi-circular halves. When the clutch lever is pulled and pressure is applied to the end of the crankshaft, it is pushed onto these thrust washers, so I assume it must be that friction which is causing the increase in the torque readings.
Is it possible that as the engine warms up and the crankshaft expands laterally, the clearance between it and these thrust washers becomes too small, decreasing the amount of oil getting in and making them bind ?? Would it be the binding that is making the knocking noise, or could the two halves be moving about ?
The crankshaft is always relatively free and perfectly smooth to turn, although there is a tight spot near Top Dead Centre where I took the torque readings, but I am assuming that this is because that's where the con-rods are in their worst position for leverage.
Any comments on this theory by any experts out there would be very welcome !! Nev.

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V7II Stone


Posted By: rapheal
Date Posted: 11 Dec 2018 at 23:31
I think you are worrying too much
swap it for a Honda
mine makes all sorts of awful noises, 15 years later its still running
I just dont listen any more, as long as the bloody thing keeps moving I am fine with it



Posted By: NevilleG
Date Posted: 12 Dec 2018 at 10:37
Originally posted by rapheal rapheal wrote:

I think you are worrying too much
swap it for a Honda
mine makes all sorts of awful noises, 15 years later its still running
I just dont listen any more, as long as the bloody thing keeps moving I am fine with it



We all have our different approaches to how we treat our bikes and mine is obviously different to yours.
Being an Ex-RAF aircraft maintenance technician, mine is based on the principle of dealing with potential problems early, before they become major failures and expensive repairs. Having maintained and repaired car and bike engines all my life, my experience tells me that this noise is not normal and it's unlikely that Guzzi would have designed it like that.
When I started this thread, I was asking for anyone out there to let me know if their bikes do the same, to try and establish if it WAS just a trait of the 750 engine, but so far, among all the replies, only one person has responded that theirs does. That being the case, I am assuming it must be unusual.
It may not be detrimental at all, but on the other hand it could be the beginnings of something far more serious. The other Breva that I had, initially made the same noise, only louder, which was later accompanied by a harsh metallic screech and carried away in a van by the chap I bought it from !
Living and riding in the remoteness of the Scottish Highlands, reliability is of paramount importance to me. Nev.

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V7II Stone


Posted By: Dave P.
Date Posted: 12 Dec 2018 at 11:10
Just a thought. Is there any mileage in contacting the vendor of your previous bike and asking him whether he found the source of the knocking and screeching? And if he did, what was it?

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TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.


Posted By: V7Chris
Date Posted: 12 Dec 2018 at 12:43
They certainly make a racket hot or cold, clutch in or out compared with many modern liquid cooled ohc engines. I have stopped listening to mine after three years ownership like Raphael.


Posted By: Brian UK
Date Posted: 12 Dec 2018 at 16:55
I admit I am surprised by the extra resistance you found whith the clutch pulled in or out. I would have expected the opposite, indeed Guzzi often suggest pulling in the clutch lever when starting to reduce the load (of the gearbox primary) when starting.



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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 13 Dec 2018 at 13:53
Originally posted by Dave P. Dave P. wrote:

Just a thought. Is there any mileage in contacting the vendor of your previous bike and asking him whether he found the source of the knocking and screeching? And if he did, what was it?


I did Dave and he initially came back to me saying that it was a bearing on the gearbox input shaft, which made no sense at all. I asked him for some more information, but got no further reply.
He also owed me a refund on the Road Tax, but despite firstly offering to repay it, he hasn't answered any more of my text or emails since. Nev.

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V7II Stone


Posted By: NevilleG
Date Posted: 13 Dec 2018 at 14:08
Originally posted by V7Chris V7Chris wrote:

They certainly make a racket hot or cold, clutch in or out compared with many modern liquid cooled ohc engines. I have stopped listening to mine after three years ownership like Raphael.


The three Guzzi's I have owned have all had exceptionally mechanically quiet engines, especially the California with its hydraulic tappets and this Breva 750 is as well, but the gearboxes make a bit of a clatter, just like old BMW's, pulling the clutch in stops that and you only hear the engine noises. When this engine is cold, it's very quiet, it's only when it's hot that it makes this noise.
I put a paint mark on the alternator's rotor and, using a timing light, found the noise coincides with the engine reaching Top Dead Centre, where the tight spot is. Nev.

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V7II Stone


Posted By: Mike H
Date Posted: 13 Dec 2018 at 16:20
Have you examined the engine oil for signs of metal particles? 'Cause if something is rubbing on something, it'd make swarf?




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"Chicken nuggets don't dance on a Tuesday."


Posted By: NevilleG
Date Posted: 14 Dec 2018 at 10:25
Originally posted by Mike H Mike H wrote:

Have you examined the engine oil for signs of metal particles? 'Cause if something is rubbing on something, it'd make swarf?




Hi Mike. Yes I have, but there is nothing visible in the oil or on the magnetic drain plug. If it was those Thrust Washers,they are probably made of steel, with a non-ferrous bearing material face, like bronze or white metal, at least ones I have come across in the past have. As you probably know, if main bearings or big-ends fail, the bits all finish up lying in the sump and it's only ball or roller bearing bits that you find stuck on the drain plug.
As this noise is only associated with the clutch being pulled in, I think it's just the extra end loading on the crankshaft that triggers some movement somewhere. God knows what !
Anyway, I will keep an eye on it, but I'm not going to start pulling the engine apart until I see if it develops any more. It might even get less as I put more miles on it. Who knows !   Nev.


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V7II Stone


Posted By: Dave P.
Date Posted: 14 Dec 2018 at 10:39
Keep us informed please Nev. Otherwise, we have a play minus the last act.

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TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.


Posted By: Mike H
Date Posted: 14 Dec 2018 at 21:35



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"Chicken nuggets don't dance on a Tuesday."


Posted By: Cylvabirch
Date Posted: 14 Dec 2018 at 22:47
For peace of mind I would take the sump off and have a good look round for debris and get someone to turn the engine over while you have a poke round levering things with a long screwdriver and a good torch to see if there is something doing something it shouldn’t.
Put some fresh oil in and a new filter.
It could still not be properly run in if previous owners have pussy-footed around on it and used extremely good synthetic oil.
My wife’s Citroen car years ago was as tight as a tick at 10,000 miles because her careful husband insisted on using only Mobil 1 and changing it at twice the frequency in the book (because I am an aerospace trained engineer originally). She was a cautious driver back then.
Ride it like you stole it for a few hundred miles, it may well improve things. If not; it’s “sh1t or bust” and you will get to the answer! 


Posted By: NevilleG
Date Posted: 15 Dec 2018 at 11:16
Your advice Cylvabirch ( We've got a nice lot of those up here in Scotland !!) is very sound and I'm planning to drop the sump off in the Spring to have a look, but whether or not it reveals anything remains to be seen.
With the Scottish winter and the forthcoming holiday period commitments looming, it will have to wait until then, but I'm determined to get to the bottom of it so watch this space.
It would have been nice to have got a bit more feedback from other Small Block owners, especially any Guzzi technicians or mechanics with any other ideas, and it seems strange that both the bikes that I've had, both being 2007 models, made the same noise, yet nobody else's do.
Mike says that "Theoneandonly" is a Guzzi mechanic and I have sent him a PM to try and start up a dialogue about it, but, as yet, I haven't heard anything from him. Nev.

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V7II Stone


Posted By: Brian UK
Date Posted: 15 Dec 2018 at 15:52
Originally posted by NevilleG NevilleG wrote:


Mike says that "Theoneandonly" is a Guzzi mechanic and I have sent him a PM to try and start up a dialogue about it, but, as yet, I haven't heard anything from him. Nev.

Baldrick is probably one of the best sources of practical information we have here, but he doesn't check in every day. Probably some sort of excuse like having a living to make.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: nab301
Date Posted: 15 Dec 2018 at 16:03
I've followed this thread with interest to the extent of  listening frequently to my own B750 when hot and pulling the clutch but as already posted not hearing anything  like you describe  , maybe a slight change in "tone" of the engine when the clutch is pulled but nothing more.
Never having stripped a Guzzi engine and  I stand to be corrected but looking at all the videos on the" this old tractor website "  I don't think removing the sump will give access to the crank thrust washer area .  It  looks like splitting the crankcases is the only way .  Maybe a borescope might but it's hard to see . 
http://www.thisoldtractor.com/moto_guzzi_technical_training_videos_eng.html" rel="nofollow - http://www.thisoldtractor.com/moto_guzzi_technical_training_videos_eng.html

Or alternatively  maybe some oil analysis?
http://www.millersoils.co.uk/services/oil-analysis" rel="nofollow - http://www.millersoils.co.uk/services/oil-analysis


-------------
Nigel
Keep smiling , it makes people wonder what you've been up to!
'19 CB125F,

'18 DL250 SUZUKI V STROM,'99 Bmw R1100S, '03Bullet 65 500, '93 MZ301 Saxon fun (offroad)


Posted By: Chris A
Date Posted: 15 Dec 2018 at 18:23
There could just be an issue with the crank end float...have seen it on several small blocks and its due to wear on the half moon shims that set the float on the crank.Does the engine speed vary when the clutch is in or out ?


Posted By: rapheal
Date Posted: 16 Dec 2018 at 15:37
Originally posted by Brian UK Brian UK wrote:

Originally posted by NevilleG NevilleG wrote:


Mike says that "Theoneandonly" is a Guzzi mechanic and I have sent him a PM to try and start up a dialogue about it, but, as yet, I haven't heard anything from him. Nev.

Baldrick is probably one of the best sources of practical information we have here, but he doesn't check in every day. Probably some sort of excuse like having a living to make.
Also its his living, and giving out advice could involve him in litigation if things went wrong

I was advised by my previous employer never to give advice to members of staff asking about electrical problems, as it could leave the company and myself open to litigation
the way they explained it was that some one may come up and ask me advice about a problem and seem to have plenty of knowledge and skill, but could be less than competent and over confident of their own abilities and end up killing themselves
even now I am wary of giving out advice without first making a full inspection of the problem
This was brought home to me when one of our senior staff asked about alterations to an old property, and I said I would only give advice after inspecting it myself, I am so glad I did not get involved in any way
he didnt want to pay for my time, it would have saved him a great deal of money and hassle
ps the one and only is a very sound bloke and really knows his stuff,
if you are still worried about the motorcycle, why not arrange to have it inspected by a professional motor cycle engineer who is familiar with this type of machine





Posted By: johnno
Date Posted: 16 Dec 2018 at 20:12
TheoneandonlyThumbs Up still owe him a quidThumbs Up

-------------
1100 sport corsa , Yam R1, guzzi 650tt rider


Posted By: Brian UK
Date Posted: 16 Dec 2018 at 21:45
Originally posted by rapheal rapheal wrote:

I was advised by my previous employer never to give advice to members of staff asking about electrical problems, as it could leave the company and myself open to litigation

I suspect the real reason is more to do with wanting to be paid for your services.

If Baldrick wants to help it's his decision. He's normally very helpful.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: Brian UK
Date Posted: 16 Dec 2018 at 21:46
Originally posted by johnno johnno wrote:

TheoneandonlyThumbs Up still owe him a quidThumbs Up

Never admit something like that in public! LOL


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: rapheal
Date Posted: 16 Dec 2018 at 22:30
Originally posted by Brian UK Brian UK wrote:

Originally posted by johnno johnno wrote:

TheoneandonlyThumbs Up still owe him a quidThumbs Up

Never admit something like that in public! LOL

Plus interest at 8 percent
I reckon a bottle of single malt by now


Posted By: rapheal
Date Posted: 16 Dec 2018 at 22:39
Originally posted by Brian UK Brian UK wrote:

Originally posted by rapheal rapheal wrote:

I was advised by my previous employer never to give advice to members of staff asking about electrical problems, as it could leave the company and myself open to litigation

I suspect the real reason is more to do with wanting to be paid for your services.

If Baldrick wants to help it's his decision. He's normally very helpful.

No they got sued big time
a plumber was asked about a problem with a heating system, and he did a sketch showing how it should work
bloke thought he was a plumber, did some serious damage as he was an idiot
company paid up, easier than going to court
we were also told never to provide a sketch or drawing of work as thats a contract 
I have been told the same by my recognised trade body
I can inspect a system and provide a report if  I intend to carry out the repairs, but i must clearly state that it is my own assessment and only covers me

Indian lady in the corner shop asked me about some electrical work for a roof extension, I had a look and gave her a quotation based on myself doing the work and providing the materials
new consumer units, split load boards, battery mains smoke detectors linked and escape lighting
she got her Uncle from Birmingham to carry out the work cos he was cheaper and family
the council refused to sign it off
no certificate , no planning notes, no test results
I got a solicitors letter threatening legal action for poor advice
gave it to my trade body
they dealt with her, the extension had to be removed and the building put back to its origional build
SO now I dont give advice, when my neighbour asked me about the three bedroom sockets not working, and how should he fix it ( he designs Aircraft Control systems)  I said get the place rewired, its about the same cost as a Co Op funeral
lots of bodgery as revealed as they ripped it out and rewired it ?





Posted By: Brian UK
Date Posted: 17 Dec 2018 at 07:41
OK, but we have now gone a little off the original subject which was about the noise from an engine.

It helps if we can keep on topic when it comes to technical issues.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 17 Dec 2018 at 09:51
Blimey fella's !!   Steady on now !
A bit of advice to help a mate is a bit different to that given by paid professionals.
In my case I was just asking if anybody out there has a similar noise on their bike and, in the case of asking a more experienced and knowledgeable mechanic, if they had come across it in their work.
With regard to the other recent posts, it would be a good idea for contributors to read the WHOLE thread before adding their comment, as things that have already been covered are being repeated. Ta!

-------------
V7II Stone


Posted By: rapheal
Date Posted: 17 Dec 2018 at 20:26
Originally posted by NevilleG NevilleG wrote:

Blimey fella's !!   Steady on now !
A bit of advice to help a mate is a bit different to that given by paid professionals.
In my case I was just asking if anybody out there has a similar noise on their bike and, in the case of asking a more experienced and knowledgeable mechanic, if they had come across it in their work.
With regard to the other recent posts, it would be a good idea for contributors to read the WHOLE thread before adding their comment, as things that have already been covered are being repeated. Ta!

 
Well I had a half day today
So I took my Breva out for a few hours to visit a friend
it makes some sort of noise that changes when I pull  the clutch in, but I am sure its always made that noise, A friends one makes a similar noise, if that helps
oh and the gears whine as well
it also has a few other odd rattles and knocks, but after 15 years if it goes bang one day I shant be too upset
When Antonio services it he changes all of the oils, oil cheap bearings expensive, and he always examines it for any metal particles, none found yet
have you ridden the machine hard until its warmed up to see if that makes a difference
they do run badly when cold
I tend to ride mine for about 5 miles gently through the gears, then when I hit the edge of town and the A40 I rev it in every gear to get it nice and hot
makes the drive box last longer as well




Posted By: NevilleG
Date Posted: 18 Dec 2018 at 11:23
To save any further confusion about my engine noise, I have now loaded the video I took of the noise on my first bike, onto Youtube. The noise is the same on my current bike but it's much quieter.
You will also hear a metallic twittering noise as I pull the clutch, which got progressively worse in the days after I took the video and is not present on my current bike. Initially that was thought to be the clutch thrust race giving up, but it could also have been associated with the knocking noise. I never got any answers from the guy who bought it back as to what had gone wrong, so that is why I am a bit concerned as to what might occur in the future.
This is the link:- https://www.youtube.com/watch?v=nD6qnv_QiIg" rel="nofollow - https://www.youtube.com/watch?v=nD6qnv_QiIg


-------------
V7II Stone


Posted By: Roadrunner
Date Posted: 18 Dec 2018 at 16:40
Hi could you put a video up of your current bike 😊

-------------
Malc


Posted By: Brian UK
Date Posted: 18 Dec 2018 at 17:13
Have you been able to check for end float on the crank?


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: George S
Date Posted: 18 Dec 2018 at 21:00
Originally posted by NevilleG NevilleG wrote:

To save any further confusion about my engine noise, I have now loaded the video I took of the noise on my first bike, onto Youtube. The noise is the same on my current bike but it's much quieter.
You will also hear a metallic twittering noise as I pull the clutch, which got progressively worse in the days after I took the video and is not present on my current bike. Initially that was thought to be the clutch thrust race giving up, but it could also have been associated with the knocking noise. I never got any answers from the guy who bought it back as to what had gone wrong, so that is why I am a bit concerned as to what might occur in the future.
This is the link:- https://www.youtube.com/watch?v=nD6qnv_QiIg" rel="nofollow - https://www.youtube.com/watch?v=nD6qnv_QiIg

I don't own a Breva but  for my peace of mind I would have to strip any bike I owned with that knocking sound. Good thing is Guzzi is easy to dismantle.
Two things spring to mind
1) split gearbox from engine check clutch for damage
2) Check crank for end float as mentioned in previous posts
Good luck


-------------
George

1994 Nevada
1962 Lightweight ducati Bevel Single
Son's 1990 1000S to borrow any time


Posted By: rapheal
Date Posted: 18 Dec 2018 at 21:59
if road dirt gets into the clutch pushrod that can make an awful noise when the bearing fails
Antonio strips and greases mine on the big service at the same time as the operating arm pivots
the bearing can seize through lack of use, or idiots using a pressure washer on the machine


Posted By: Brian UK
Date Posted: 18 Dec 2018 at 22:05
True, Guzzis are not sealed against pressure washers.



-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 19 Dec 2018 at 11:23
Originally posted by Roadrunner Roadrunner wrote:


Hi could you put a video up of your current bike 😊


I don't think there would be much point in doing that because, as I have explained before, it doesn't make that horrible twittering screeching noise (I wouldn't even consider riding it if it did !) and the knocking noise, although present, is nothing like as loud.
I have decided to just keep an eye (ear !) to it and tear the engine/gearbox apart if it gets worse.
One thing that has been mentioned, by Raphael I think, concerning the push rod and cup is another possibility, if the push rod, which runs through a hole in the gearbox input shaft and onto the centre of the cup, is lacking lubrication or a bit corroded. Can that be accessed without taking the gearbox off ? Hmmm !
Nev.

-------------
V7II Stone


Posted By: George S
Date Posted: 19 Dec 2018 at 12:07
I believe that that push rod and thrust bearing pulls out from rear of gearbox. It does on earlier models. Maybe have to remove swingarm. Thinking about it I would check thrust bearing and rod first.

-------------
George

1994 Nevada
1962 Lightweight ducati Bevel Single
Son's 1990 1000S to borrow any time


Posted By: Brian UK
Date Posted: 19 Dec 2018 at 16:53
Yes the thust bearing is pressed into the rear cover of the gearbox from the outside.
But you have to remove the swinging arm to get at it.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: rapheal
Date Posted: 19 Dec 2018 at 22:52
useful tip from my mechanic ( not me I use a hammer on everything)
when you remove the rear wheel, put a wooden block or an axle stand under the swing arm
otherwise when you undo the shock absorbers it will droop down and the front will contact the gear linkage and bend the short operating arm or even snap it 



Posted By: Brian UK
Date Posted: 20 Dec 2018 at 09:21
Good tip, and it's heavy with the bevel drive attached.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 20 Dec 2018 at 09:59
Thanks Guys, I was planning to take the bevel box and swing arm off in the Spring anyway, to re-paint them. Nev.

-------------
V7II Stone


Posted By: rapheal
Date Posted: 21 Dec 2018 at 23:20
Originally posted by NevilleG NevilleG wrote:

Thanks Guys, I was planning to take the bevel box and swing arm off in the Spring anyway, to re-paint them. Nev.

I engraved the reg no on mine while Antonio had it out
if it ever gets nicked its a quick way to prove its mine
before I bash some ones head into it !!
I also did the wheels and lots of other bits


Posted By: NevilleG
Date Posted: 10 Apr 2019 at 12:42
For those who might still be interested, over the last couple of months I have been stripping the engine apart and,essentially, found very little wrong with it.
After all the input from various contributors and my own thoughts on the cause, I concentrated on the clutch assembly and crankshaft, but checked out all the other parts associated with the clutch operation as well, including fitting a new clutch release bearing.
At 17368 miles, I found the clutch was all in perfect condition and the only thing that I could find wrong with the crankshaft assembly was some uneven wear on the rearmost half thrust washer. The design of how this half washer is located and retained can possibly lead to a build-up of oil-borne debris behind it through a small oil passage, which I believe had moved it rearwards and caused some wear at that point. This could also reduce crankshaft end-float.
With new thrust washers fitted, crankshaft end-float measured up at 5-thou and I decided to use Loctite 603 to fix them against their locating faces to prevent any future lateral movement.
The crankshaft main bearing shells and journals were unmarked and had no measurable wear, however it was surprising to find how much running clearance Guzzi give the crankshaft. With no oil film, there is much more movement than I would have expected, but I had no means of accurately measuring what it was.

After reassembling and refitting the engine, the noise is still there and so my conclusion is that when the oil is hot and thinned down, the end force applied to the crankshaft upsets its balance sufficiently to allow it to float in the vertical plane of the main bearing clearance. When the engine is cold, the oil is thick enough to provide a better cushioning effect and reduce the movement.

The main bearing clearance is probably more suited to the age of thicker Mineral oil, despite Guzzi recommending modern fully synthetic grade, but a brief experiment recently with some "Elf 20w/50 motorcycle" mineral oil made no improvement and "Duckhams 20w/50" of the 1960's is sadly no longer available.

No doubt my bike will run on happily and reliably for many more miles, but it's annoying to have to put up with something like this that just doesn't seem right somehow.   NEV.

-------------
V7II Stone


Posted By: Mr Grumpy
Date Posted: 10 Apr 2019 at 13:27
So it is part of the character then.

I've changed all the oils on my B750 this week. It doesn't seem to have made any difference to the way the bike sounds.  


Posted By: nab301
Date Posted: 10 Apr 2019 at 20:26
Originally posted by NevilleG NevilleG wrote:

For those who might still be interested,   NEV.

Thanks for posting  , Interesting  findings..


-------------
Nigel
Keep smiling , it makes people wonder what you've been up to!
'19 CB125F,

'18 DL250 SUZUKI V STROM,'99 Bmw R1100S, '03Bullet 65 500, '93 MZ301 Saxon fun (offroad)


Posted By: Brian UK
Date Posted: 11 Apr 2019 at 20:27
I suspect the noise comes from the gearbox input shaft.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: NevilleG
Date Posted: 12 Apr 2019 at 13:45
Originally posted by Brian UK Brian UK wrote:

I suspect the noise comes from the gearbox input shaft.


I don't think you've thought that through Brian !

The clutch operating rod passes down the middle of the gearbox input shaft and pushes the pressure plate away from the friction plate. The friction plate, which is mounted on the splines of the gearbox input shaft, then stops rotating, as does the gearbox input shaft.
If it isn't rotating and has no other force acting on it, how can it be making any noise ???
I checked the gearbox input shaft bearing, which was perfect, but fitted a new clutch thrust race, which is under load and could have been the culprit, as a matter of course. Nev.

-------------
V7II Stone


Posted By: rapheal
Date Posted: 19 Apr 2019 at 20:33
my one sounds like a bag of spanners some days
I took sage advice from the late Ken Craven
stop worrying about it 
unless it gets worse



Posted By: Andyb
Date Posted: 23 Apr 2019 at 20:32
I start worrying when the noise stops.......
Andyb


Posted By: Bugsy
Date Posted: 24 Apr 2019 at 15:31
Originally posted by Mr Grumpy Mr Grumpy wrote:

So it is part of the character then.

I've changed all the oils on my B750 this week. It doesn't seem to have made any difference to the way the bike sounds.  

Ditto; with some engine noises that sound "appropriate" for a push rod, air cooled engine.


Posted By: Brian UK
Date Posted: 24 Apr 2019 at 22:04
I can't see how changing the oils will affect the sound, unless there wasn't enough there before.


-------------
Brian.

Better 5 minutes late in this world than years early in the next.



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