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T5 1983 850cc

Printed From: guzziriders.org - moto guzzi forum
Category: Technical
Forum Name: Big Block Tonti
Forum Description: Spada, Le Mans and Cali
URL: http://www.guzziriders.org/forum_posts.asp?TID=8321
Printed Date: 23 Jul 2018 at 12:21
Software Version: Web Wiz Forums 12.00 - http://www.webwizforums.com


Topic: T5 1983 850cc
Posted By: Surfrider Barry
Subject: T5 1983 850cc
Date Posted: 08 Jan 2018 at 21:32
Hi all I'm new here and to Guzzis I've bought a 1983 T5 which is very neglected and the right cylinder is not firing until the revs get up to about 3,000 compression is 150 psi left and 130psi right (I've checked valve clearance) would that cause this? It had new rings fitted buy some previous owner but I'm thinking that the bore might be damaged is it worth getting them re- coated or replace the barrels (just thinking ahead of strip down) the other question is has anyone bought breaded brake lines from Wesmoto and were they happy with their products? That's all for now I'm sure I'll have many more questions soon and thanks for any advice and for letting me join this forum.



Replies:
Posted By: Brian UK
Date Posted: 08 Jan 2018 at 22:09
I would think in terms of lapping the valve seats in first. Probably the RH exhaust valve is not too good.
But 130 isn't really low enough to cause problems.
 
Other things to check, spark plugs - try swapping them left to right, see if the fault changes too. Same can apply to HT cables and coils.
 
Is one carb out of tune? That could give the problem you have too.


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Brian.

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


Posted By: Surfrider Barry
Date Posted: 08 Jan 2018 at 23:04
Thanks Brian I thought 130 would still be good enough but being new to Guzzis I thought I'd ask I did switch plugs with a little bit better and it has good sparks with the plug resting on the head. I'll do the coils and lead changes first and see what happens. To be continued


Posted By: Surfrider Barry
Date Posted: 09 Jan 2018 at 05:35
I put new plugs and leads in today and it runs better but still when I take the left plug cap off it stalls but when I take the right lead off it slows but doesn't stall and theirs a lot of back pressure when I removed the dipstick at idle. It's got the breathing to the frame but there's no ball valve in the line is this normal?


Posted By: johnno
Date Posted: 09 Jan 2018 at 10:48
Is your t5 still on points ?

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GSXR1100 L ,Moto Guzzi 650tt/ntx.750xpa,t5 850.1100 sport,1100 sport corsa rider


Posted By: Surfrider Barry
Date Posted: 09 Jan 2018 at 11:10
No points Pirana electronic ign


Posted By: Mike H
Date Posted: 09 Jan 2018 at 18:00
Is the trigger magnetic or optical?

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


Posted By: Surfrider Barry
Date Posted: 09 Jan 2018 at 19:23
I'm sure Mike how do you tell? I'll take the cover off today and have a look and see if I can post a picture.


Posted By: Brian UK
Date Posted: 09 Jan 2018 at 21:20
If it's optical, dirt on the pickups can cause a misfire. Not uncommon. Clean them.
 
 
This is why it always helps to give a full description of things that are not standard.


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Brian.

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


Posted By: Surfrider Barry
Date Posted: 09 Jan 2018 at 22:13
I will clean and I should have said elect ign sorry, the other question do I need to keep the exhorts cross over equalizer thing or can I just have 2 independent pipes? I've just been reading about chroming failed in the bore so will drain oil today as well. The guy that I bought it off didn't have much history and it has very clean oil so I'm very weary


Posted By: Brian UK
Date Posted: 09 Jan 2018 at 22:50
I thought they had gone to Nikasil by 1983.
 
The exhaust cross piece does help mid range and getting the balance between the pots right.


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Brian.

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


Posted By: Surfrider Barry
Date Posted: 10 Jan 2018 at 00:38
Thanks Brian    I have just finished cleaning the sump and all parts in it and all is good no debris at all and it looks I'll have to keep the cross over exhaust pipe. Can anyone tell me an equivalent oil filter to car type or do I have to go genuine?


Posted By: Jim Mac
Date Posted: 10 Jan 2018 at 08:48
Gutsibits list it as  UFI 23 149 00  - its what i boght for my '86 T5  costs £9.70 plus post,  order up any small parts you need at the same time and save on postage

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Norge 1200 GT 8v   T5 Polizia
Too old to die young


Posted By: theone&onlymin
Date Posted: 10 Jan 2018 at 08:59
On the Newtronics / Piranha box disconnect the rectangular plug held in by two wee Philips screws. The small blade terminals may need a clean / degrease.

Check your plug leads are pushed fully home into the coils.

Check the spade connectors on the coils and give them a nip up.

Cheers
Min


Posted By: Brian UK
Date Posted: 10 Jan 2018 at 09:31
Opie Oils also sell the filters, get a forum discount too.
 
Any cross referenced filter will work though.


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Brian.

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


Posted By: Surfrider Barry
Date Posted: 15 Jan 2018 at 20:32
I've done all the cleaning of the ignition terminals and triggers ,oil change and cleaned and checked sump now waiting for braided brake hoses before giving it a run to see if it's firing good on both cylinders. Now I have been checking out carbi choices and the TM Mikuni 38mm flat slide non accelerated pump carbi is recommended, has anyone fitted these and had good results? I'm also looking at fitting Lafraconi mufflers which should help the breathing.


Posted By: Mike H
Date Posted: 16 Jan 2018 at 00:33
Try not to do too many things at once, or you could get in a right muddle. Fix the misfire first. The other stuff could make the situation worse or add more problems but you won't know which extra thing you did caused it.

Originally posted by Surfrider Barry Surfrider Barry wrote:

I put new plugs and leads in today and it runs better but still when I take the left plug cap off it stalls but when I take the right lead off it slows but doesn't stall

If memory serves Haynes manual says take one cap off, should idle a few seconds then stop, ditto other side, then idle settings for carburettors is correct.

Having said that however you MUST NOT disconnect a spark plug with the engine running if it has electronic ignition.

Quote and theirs a lot of back pressure when I removed the dipstick at idle.

Never heard of doing this before and can't think why one would want to.


Originally posted by Brian UK Brian UK wrote:

I thought they had gone to Nikasil by 1983.
 
The exhaust cross piece does help mid range and getting the balance between the pots right.

Main function of a crosspipe is to tune the downpipes to a specific length, this causes negative pressure pulses to go back up the pipe to the head and scavenge some more exhaust gas out, at a specific rpm, so removing the crosspipe may very well cause a reduction in engine output at that rpm. Some designs have two crosspipes (e.g., Le Mans) so exhaust scavenging occurs at two different points on the rpm range. Somewhere I have a book (or did have) that explains it all.


HTH



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


Posted By: Surfrider Barry
Date Posted: 16 Jan 2018 at 23:03
I have changed the oil in the final drive and found the level plug thread just about striped and wonder if there is a way of helli coiling a new thread without stripping the drive to pieces. Anyone else have this problem?


Posted By: Mike H
Date Posted: 16 Jan 2018 at 23:42
Yes and it was recomended that it has an insert, as the casing wall is not thick enough to take a helicoil. You need a freindly neighbourhood engineering works.

They did do it without it having to be stripped to the bare casing, but it needed thoroughly flushing out afterwards to get rid of any swarf.

On mine both level & drain holes needed doing.


-


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


Posted By: Ken-Guzzibear
Date Posted: 17 Jan 2018 at 21:48
850 T5 works well on the round phf 30 carbs best thing about T5 engine is the 1000cc cylinders/ pistons fit straight on the only square cyl engine that is compatible according to Guzziology .....the 850 T5 engine is as powerful and better top speed than the standard V1000 engine in the G5/Convert/Spada apparently fit the round carbs with triangular pump at the top back edge they work real well .....

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The Older i Get, The Better I Was


Posted By: Surfrider Barry
Date Posted: 17 Jan 2018 at 22:33
I thank Ken for your advice but im being recommended by Mikuni Australia to use the TM 38mm flat slide without accelerator pump and expressed concern about being to big when the Moza has 36mm carbis and they said the big Ducatis all fitted these 38s in the 80s with good results and they also said the 34mm carbis would do the job to so what are the experienced good people on the forums thoughts?


Posted By: Brian UK
Date Posted: 17 Jan 2018 at 22:47
What's the inlet port diameter?

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Brian.

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


Posted By: Surfrider Barry
Date Posted: 18 Jan 2018 at 09:53
I'll take the carbis off tomorrow and measure Brian and strip them down and give a good clean and blow air through their canals. Did run it today with coils reversed but no change it seems to not fire cleanly on the right side but not the left until about 3 to 4K revs then smooths out nicely I'll post results tomorrow after I clean the carbis


Posted By: Ken-Guzzibear
Date Posted: 18 Jan 2018 at 11:13
T5 are 30mm carb standard I think you can fit the cali type 36 ....there will be back pressure in the sump with the plug out which is why there is either a ball valve breather atop the sump OR a Le mans breather with flapper valve..nb the ball valve works best ...loads of info on the Aussie AIGOR site .....Never seen Mikhunis on a guzzi in the UK seen one with the BMW type carbs on it

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The Older i Get, The Better I Was


Posted By: cyclobutch
Date Posted: 18 Jan 2018 at 13:11
Bing

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Butch
V50 II - 'The Black Pearl'
T3 - 'Blue'
Eldo Loop - 'Jug'


Posted By: Mike H
Date Posted: 18 Jan 2018 at 13:51
Large dia. carbs will give poor slow speed running and worst fuel economy, 30mm works very smoothly for small throttle openings, which to be honest is most of the time, and better mile per gallon, when I changed from 36mm DellOrto to 30mm I got an extra 10 mpg. From low mid 40's, to high 40's even 50.

HTH



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


Posted By: Brian UK
Date Posted: 18 Jan 2018 at 14:25
But pumper carbs are the ones to avoid if fuel consumption matters.
I disabled the pumps in the 36mm Dellortos on the SPIII, and fuel consumption went up to the mid 60s mpg. Precious little difference on acceleration too. (Well that's what a friend on his Centauro said when he followed me).


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Brian.

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



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