RC24 light valve rust from sitting. Advise appreciated.

I picked up this 750 that has been sitting for at least 5 years in a basement. The first thing I did was lube the cylinders and cam, let sit overnight and turn it. It turns with the standard resistance. I have not had a chance to do a compression test on it. I noticed some light rust flakes on the edge of a couple of intake valves.

Short of pulling the heads, does anybody have advice for cleaning these valves or should I just leave it alone?

Thanks

-Ty

 

I'm pretty sure you don't want to tear the heads down and replace the valves, but that would be the only way to completely fix it.

The stems are already pitted, which certainly will hamper the flow and could potentially score the guides. Also, the valves that were in the open position are possibly rusted at the valve head, meaning that compression loss might be experienced, due to the rust not allowing the valve head to seal completely against the seat. This could potentially hammer the seat if the engine is run. It's up to you, but there really is no way to completely rectify the problem without removing the heads and cleaning everything up.

I say run it until it blows, then spend a year or two trying to source the parts to fix it correctly.

 

will 700 heads work?

No rust on the stems that I can see...just a spot here and there right above the seats. I was thinking of maybe using some kind of solvant to attack the rust (PB catalyst) before I run it and check compression.

Ive got some really clean low mileage 700 heads in the corner. Worst case, Ill swap cams and throw them on.

Thanks

 

THE PB Blaster should serve to loosen rust, just run the bike.

 

Lucked out. She runs strong. For now Im just going to ride. Ill get #s up here once Im back into it.

 

You do not need to do anything. Just check the fluids and run it until hot, and then change the oil and the coolant.