ra12r
Zone Head
Posts: 919
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posted July 30, 2005 05:21 AM
Cam Gear Damage
Discovered something new again...... I hate this!!! After having an exhaust valve to hit the piston and then break off and be driven into the head, everything was repaired and replaced. Upon reassembly, I slightly noticed a small issue with the cam chain tracking while degreeing the cams. Nothing big, but odd. But the cam chain was acting like a rear wheel sprocket when it or the chain gets stretched and worn. BUT VERY MILD, so I rationalized it seeing it was a new cam chain.
Got the motor running and it was fine until I did a road test. At this point no noise until i rolled into the throttle at about 4000 rpms in 6th. The motor had major top end noise! Went back to try and adjust the cam chain tension, thinking it was not adjusted correctly. Tried it in first gear this time in the parking lot. No problem until i tried a roll on, then the same intense top end noise!
Took the pan off and found metal (silver) with plenty of dust. Took the motor back out and watched the tracking of the cam chain again while manually rotating the motor. The exhaust cam gear (APE adjustables) is NOT allow the chain to sit deep. And the new chain tries to "ride up and out" of the gear teeth. The cam sprocket is ruined from the dropped valve. Complete motor has to be disassembled for cleaning now.
Dropped valves can cause cam sprocket damage WITHOUT breaking the cam chain.
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All must bow to the "Ra Supremecy"...
  
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osti33
Needs a job
Posts: 2973
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posted July 30, 2005 11:25 AM
 Edited By: osti33 on 30 Jul 2005 12:27
Sorry to hear about your problems. However that is good info for everyone else. The noise it made. Did it sound like cam chain noise or did it sound like something else?
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extremelean
Pro
Posts: 1651
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posted July 30, 2005 12:50 PM
If you dont already have it in mind....replace the cam chain too!!!
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entropy
Moderator
Posts: 8671
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posted July 30, 2005 01:36 PM
ra12,
At one point the Cheeseman noticed that my cam chain seemed to be "riding high" on the (Muzzy) cam sprockets, but when we looked at it closely we saw that the bottom of the chain link was in reality only .005" +/- +/- (eye ball) from the top of the tooth. In other words on my motor the chain COULDN'T ride any deeper in the sprocket. It does LOOK like it is riding high but it can't ride any deeper.
BTW: I always replace the cam chain...
BTW: I have a set of old Web cams with (APE??, Muzzy??) adjustable cam sprockets on em, and the cain sits just as high on them as it does on the "new" Muzzy sprockets.
If your cam sprockets are ruined, I am sure the teeth show some REAL obvious wear???
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ra12r
Zone Head
Posts: 919
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posted July 30, 2005 08:13 PM
Well what happens is that after about 5 teeth is that the cam chain and the sprockets no longer mesh.... IE: just like a worn rear wheel sprocket or stretched chain. Then the chain begins to ride up or get caught on a tooth.
I am replacing both sprockets. Visually I cant see anything just looking at the sprocket that looks bad. It is real subtle. Also, I got to thinking and I have about 15 thousand miles on the sprockets. But I think somehow the drop valve caused this secondary damage. Maybe the valve damage was caused by the cam chain jumping last time?!?!
The noise was similar to the noise you heard when a chain and rear tire sprocket is bad. Major clicking and brbrbrrrr noise...... sorta like a diesel but a different pitch but more like the rear sprocket...... how's that (smile)
I too also replace the cam chain. This is about my 4th or 5th chain and was brand new on the same sprockets. I am going to replace the sprockets before any more dissessembly to make sure that the problem is fixed during manual rotation.
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All must bow to the "Ra Supremecy"...
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Ra12r
Zone Head
Posts: 919
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posted August 06, 2005 05:49 AM
Replaced the cam sprockets and that stopped all the issues. Visually it is very difficult to see the difference between the old and the new, however, the chain demonstrates the difference.
I believe now that this caused my exhaust valves to hit on the previous build.
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All must bow to the "Ra Supremecy"...
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osti33
Needs a job
Posts: 2973
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posted August 06, 2005 07:03 AM
Glad to hear you got it fixed.
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slug
Pro
Out in search of my mind...
Posts: 1433
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posted August 06, 2005 07:36 PM
good news!
   
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