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Squealing noise around stator and slow return to idles

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G-Man
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Post by G-Man » Tue Oct 13, 2015 4:57 am

Easier with a video but not as good as being there. Sounds like something is running dry up in the top end. Could the timing be out?

Have you tried pulling the valve caps off to have a look? Are the rocker shafts in correctly? They are two different sizes.

I see the electronic ignition module is that recent? Could you have d e anything t block oil feeds?

G
Brickyard wrote:
G-Man wrote:Under what conditions does the squeak occur? Is it continuous or cyclic?

What condition is the starter clutch in? Rollers? Springs? Any signs of damage?

Starter?

Main bearings?

Post pictures.......

G
Brickyard wrote:
G-Man wrote:If you look carefully, there are slots in the part next to the screws. Take a punch or small chisel and 'stake' the edges of the screw (when tight) into those slots.

G
Pulled rotor, attempted to tighten screws but they went no where, shaved sharp edges, and squeal or "squeak" still exists. Can't really spot where the sound is coming from, but it doesn't sound like the rotor. It sounds the same on both sides of engine. I'll adjust the cam chain and try again
Here you go G, a video is so much better than me trying to describe this issue...

https://www.youtube.com/watch?v=DcdEntqYImw
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

Brickyard
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Post by Brickyard » Tue Oct 13, 2015 6:19 am

G-Man wrote:Easier with a video but not as good as being there. Sounds like something is running dry up in the top end. Could the timing be out?


Have you tried pulling the valve caps off to have a look? Are the rocker shafts in correctly? They are two different sizes.

I see the electronic ignition module is that recent? Could you have d e anything t block oil feeds?

G
Brickyard wrote:
G-Man wrote:Under what conditions does the squeak occur? Is it continuous or cyclic?

What condition is the starter clutch in? Rollers? Springs? Any signs of damage?

Starter?

Main bearings?

Post pictures.......

G
Brickyard wrote:
G-Man wrote:If you look carefully, there are slots in the part next to the screws. Take a punch or small chisel and 'stake' the edges of the screw (when tight) into those slots.

G
Pulled rotor, attempted to tighten screws but they went no where, shaved sharp edges, and squeal or "squeak" still exists. Can't really spot where the sound is coming from, but it doesn't sound like the rotor. It sounds the same on both sides of engine. I'll adjust the cam chain and try again
Here you go G, a video is so much better than me trying to describe this issue...

https://www.youtube.com/watch?v=DcdEntqYImw
Q: Easier with a video but not as good as being there. Sounds like something is running dry up in the top end. Could the timing be out?

A: Timing was verified at idle and at advance about 3 weeks ago.

Q: Have you tried pulling the valve caps off to have a look? Are the rocker shafts in correctly? They are two different sizes.

A: Big intake and small exhaust rockers IIRC were verified before the last time then engine was off, and in accordance with rebuild documentation from LM. Intake/exhaust cams did seem abnormally close to exhaust/intake rocker arms when I did my best to line everything up as I thought it should be, and possibly moved around causing the metal shavings? I'll find out after work today when I pop the top off.

Q: I see the electronic ignition module is that recent? Could you have d e anything t block oil feeds?

A: E-ignition was the first mod I made about 3 years ago, and has never been an issue. Im not sure what I would have done to block the oil feeds, but I didn't do anything to clean them up, maybe thats just as bad? The head was brought to a shop to be tank cleaned, and I didn't think to put anymore thought into it. Upon purchasing the bike, i did have the cam tensioner ball disintegrate on me, and did my best to superficially clean old, rubber particles out of the bottom end, but I never got around to taking the bottom end apart to deep clean.

I should have the results of my last top end rebuild after work today.

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G-Man
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Post by G-Man » Tue Oct 13, 2015 6:58 am

Apologies for the basic question and typos. I am travelling at the moment.

Will be interesting to see what you find. The shavings suggest matal to metal contact somewhere.

Are the rockers clearing the valve caps?

G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

Brickyard
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Post by Brickyard » Tue Oct 13, 2015 9:02 pm

Inside the cylinder head looks exactly like i left it. While attempting to reproduce the squeak, I believe I have tracked it coming from the right cylinder spark plug hole.

Why do I get a bunch of errors when trying to post pictures!!

Brickyard
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Joined: Tue Mar 26, 2013 6:49 pm
Location: North Florida

Post by Brickyard » Tue Oct 13, 2015 10:03 pm

Cant upload photos, so...

Pulled cylinder head and barrel expecting to find a broken piston ring on the right cylinder. Instead I found a lightly scraped left piston and moderately/heavily scraped right piston both on the back bottom side of the piston. IIRC, they were scraped the last time I reassembled the motor and passed them off as good.

The right piston is COMPLETELY dry; no oil at all, while the left piston is well lubricated right under the rings. What appears to be a right side oil port in the rear part of the block, close to the cam chain wheel, is holding residual oil (apparently clogged), and the left side port is clean and free of oil. Im about to stick something in the right side oil port to clean it out.

While im at this point of tear down, what other ports should i be looking to ensure are clean, if there are any? Also, there are still remnants of the disintegrated cam chain roller in the block. I was thinking about flushing the bottom end with mineral spirits while leaving the oil drain bolt off and cycling the crank a few times. Is there a known better way to superficially cleaning the bottom end without disassembly? As always, thanks in advance for the response!

Brickyard
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Joined: Tue Mar 26, 2013 6:49 pm
Location: North Florida

Post by Brickyard » Tue Oct 13, 2015 10:50 pm

Videos will have to do until I can post pictures...

https://www.youtube.com/watch?v=vps9ClM ... e=youtu.be

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G-Man
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Post by G-Man » Wed Oct 14, 2015 5:05 am

Brickyard

Those pistons look pretty nasty. The oil ways you show in your video are there to catch oil flowing back down from the top end (cam tunnel) to provide a bit of feed for the main bearings. The main oil source to the main bearings is direct from the oil filter and is related with the oilway you point to at the front of the top crankcase.

I suspect you have debris in your oilways and this debris could be blocking flow into the crank and then up to the cylinder / piston area. The piston / cylinder lubrication comes as oil thrown of the crank / big end.

Image

You really need to strip the motor and clean all those oilways tyou can find as well as cleaning the the centrifugal oil filter and filter screen around the oil pump. If you can, you should get the crank stripped and cleaned, as well, No oil to that piston probably means that the oilways in the crank are blocked.

Image

The debris from the 'dry' piston is going to make the situation worse.

G


Brickyard wrote:Videos will have to do until I can post pictures...

https://www.youtube.com/watch?v=vps9ClM ... e=youtu.be
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

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