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Le Mans Unusual Noise

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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr 2017 at 22:14
Never liked liquid manometers for this reason...

Before going mad dismantling things, are valve clearances correct?

Also what about other adjustments, ignition timing, carburettors etc. - balancing of which is what the manometer is for - won't tell you if it's pinking or not tho unfortunately, nor the fuel mixture strength.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote kateguy Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr 2017 at 23:18
Check you aint simply got a tight tappet holding a valve open first....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr 2017 at 23:21
Exactly!

It occurred to me the rattling on the left is merely the LH cyl. tappets working normally!

Or another way of putting it, RH side is unusually quiet...




Edited by Mike H - 25 Apr 2017 at 15:28
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GuzziPaul Quote  Post ReplyReply Direct Link To This Post Posted: 01 May 2017 at 17:03
Stripped the RHS pot down and had the valves out, using a magnifying glass (left eye is still a problem) managed to identify the exhaust valve had a little bit of  carbon ridge on it. Cleaned it up by lapping the valve (did the intake as well).
All back together now and did a quick compression test and both sides are now roughly equal around 150. Not run it up yet, that a job for tomorrow.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GuzziPaul Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2017 at 11:53
Although I still have an eye problem I took the bike for its MOT (passed no problem). Now I can actually ride it rather than just playing with it in the garage the noise is still there.

I've had the bike for a year and a bit and thinking about it the noise has always been there, I just put it down to the "usual" Guzzi noises, it is definitely noisier on the left side than the right, despite multiple attempts at valve adjustment.
I'm now thinking "small end" . Might strip the left side tomorrow and see if there is any "wibble" on the piston (fore and aft) but not take the gudgeon pin out.
Any other way of identifying small end failure?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2017 at 13:17
I have had a Gudgeon pin circlip go they wear from the inside Guzziology recommends replacement when ever the engine is apart ..... when they let go it stuffs the bore big time
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2017 at 22:58
Originally posted by GuzziPaul GuzziPaul wrote:

I've had the bike for a year and a bit and thinking about it the noise has always been there, I just put it down to the "usual" Guzzi noises, it is definitely noisier on the left side than the right, despite multiple attempts at valve adjustment.


You've reminded me there was a story years back that the cams are not all quite alike, firstly they are supposed to be ramp cams, meaning the 'slack' is taken up smoothly by a shallow rise before the lobe proper comes around, but the story said not quite for lefthand exhaust so it always rattled more than the others.

When I had not long had my Spada I was always fiddling with the tappets trying to get them quieter, someone else another Guzzi owner saw me doing this one day and basically said you're wasting your time you can't achieve it.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 05 May 2017 at 23:12
Originally posted by GuzziPaul GuzziPaul wrote:

Although I still have an eye problem I took the bike for its MOT (passed no problem). Now I can actually ride it rather than just playing with it in the garage the noise is still there.

I've had the bike for a year and a bit and thinking about it the noise has always been there, I just put it down to the "usual" Guzzi noises, it is definitely noisier on the left side than the right, despite multiple attempts at valve adjustment.
I'm now thinking "small end" . Might strip the left side tomorrow and see if there is any "wibble" on the piston (fore and aft) but not take the gudgeon pin out.
Any other way of identifying small end failure?


If you don't remove the pin and piston it may be difficult to tell where any "wibble" originates.Pin to small end or pin to piston.Just a thought.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote theoneandonly Quote  Post ReplyReply Direct Link To This Post Posted: 06 May 2017 at 18:17
have you put your fingers against the carb slides when it is running ? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GuzziPaul Quote  Post ReplyReply Direct Link To This Post Posted: 09 May 2017 at 20:49
Originally posted by theoneandonly theoneandonly wrote:

have you put your fingers against the carb slides when it is running ? 
NoConfused what will this tell me? what am I looking for?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2017 at 00:23
And, how do you do that then? Wacko


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Post Options Post Options   Thanks (0) Thanks(0)   Quote cyclobutch Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2017 at 12:09
Originally posted by Mike H Mike H wrote:

And, how do you do that then? Wacko



Unscrew and remove the bell mouths. Stick your fingers in the back.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dukedesmo Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2017 at 13:10
Originally posted by Dave P. Dave P. wrote:

Originally posted by GuzziPaul GuzziPaul wrote:

Although I still have an eye problem I took the bike for its MOT (passed no problem). Now I can actually ride it rather than just playing with it in the garage the noise is still there.

I've had the bike for a year and a bit and thinking about it the noise has always been there, I just put it down to the "usual" Guzzi noises, it is definitely noisier on the left side than the right, despite multiple attempts at valve adjustment.
I'm now thinking "small end" . Might strip the left side tomorrow and see if there is any "wibble" on the piston (fore and aft) but not take the gudgeon pin out.
Any other way of identifying small end failure?


If you don't remove the pin and piston it may be difficult to tell where any "wibble" originates.Pin to small end or pin to piston.Just a thought.

When I rebuilt my Lemans engine after the pistons hit the exhaust valves, I found one of the little end bushes (LH side) was loose in the rod. I think it had been like that for some time rather than caused by the piston/valve interface and it didn't seem to be causing any problem, hadn't noticed any noise but I replaced it anyway.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote theoneandonly Quote  Post ReplyReply Direct Link To This Post Posted: 11 May 2017 at 11:06
a knocking carb slide makes a noise just like a cam follower dieing 
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 11 May 2017 at 21:38
Originally posted by cyclobutch cyclobutch wrote:

Originally posted by Mike H Mike H wrote:

And, how do you do that then? Wacko



Unscrew and remove the bell mouths. Stick your fingers in the back.


Oh right yes of course. (Forgot a LM was like that Embarrassed )


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