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Author Topic: Bent Valve  (Read 45 times)

Offline vontresc

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Bent Valve
« on: May 31, 2026, 02:50:02 PM »
It all started with starting issues on my R65. the right side would fire, but it would take a bt of time for the left side to run ok. I ended up rebuilding the carbs over the winter, and also found that the left side ignition leads were crap so I replaced those also. With that fixed it ran a bi better, but the odd starting kept happening.

Fast forward a bit, and now I am getting ZERO compression on the left side. So I pull the valve cover, and I noticed that the intake valve is stuck about 2mm open.

Next step was to pull the heads, and see the issues.

Turns out there was some contact with the piston, and it looks like the intake valve got bent.

So first off, is there a valve compressor you guys can recoomend?
Second, I figure this may need some extra work on the head. Do you have any recommendations for a place? I am in Wisconsin, so local would be ideal.
Third, I am already planning on checking the timing to see if that was the cause. If the timing is ok, what else could cause this?

Thanks

Peter

Offline Bob_Roller

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Re: Bent Valve
« Reply #1 on: May 31, 2026, 06:35:42 PM »
Go to the Airheads group website do a search abs see if there are any repair shops in your area .
'81 R65
'82 R65 LS
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!

Offline Barry

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Re: Bent Valve
« Reply #2 on: June 01, 2026, 03:13:36 AM »
I don't recall ever hearing of valve piston contact due to cam timing error so I assume the valve must have stayed open due to sticking in the guide and got clobbered by the piston that way. It's certainly not a common problem.
Barry Cheshire, England 79 R45

Offline vontresc

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Re: Bent Valve
« Reply #3 on: June 01, 2026, 08:32:14 AM »
yeah the more I think about it, i think it was likely a stuck valve that got hit. I was having what an airplane friend called "morming sickness" where it seems that ne of the valves sticks open until the engine warms up, and then runs ok.

Peter