Bent Valves?

[Brian]

Fellow XS'ers,

Recently sold my 79 Special (which if loved) because I picked up an 80 MS with ~2,000 miles on it. You may remember the post on the MS project, and it's a great bike now.

In the process of selling the 79, someone reached out to me with an 80 MS he wanted to do a partial trade on. It rand great until he pulled out the CCT because it was leaking. And you guessed it- slipped the cam chain in the process. he said it still ran, but now won't start. I am thinking "run don't walk" from this bike as it likely has bent valves. Got me wondering if there is a decent way to check- look for damage on the top of the piston or maybe a compression test?

Thanks to you guru's out there for always being there for us amateurs!!

BTW, here's a picture of my 80 MS after some work:

[DiverRay]

If you think it has a bent valve, but it still seems to want to run, DO the compression check. It will tell you which one is bad, or if more than one is bad. As far as a fix, I believe the 80 up valves are still available, so the fix should not be too bad.
Wish MY midnight looked that good!

[SFerinTEXAS]

I suppose it goes w/o saying that the chain needs to be put right before a compression test can be done. Happened to me on my 79 a few years ago same thing from my ignorance. First clue was it would barely run, very hard to start. Lucky after fixing the chain no damage and all was fine.

[ViperRon]

I'd pop the valve cover align the timing put in the adjuster and slowly rotate by hand and see if you can turn it over by hand without any binding, If it turns by hand then do compression check if you have a cylinder in doubt poor some heavy weight oil in just a little and if its rings the compression jumps way up if a valve will not help after a few turns. If you here clicking stop immediately. On Ebay a few years back I got a complete set of intake and exhaust valves with springs for about $30 so if only valves a head gasket and valves. If a piston is cracked a little more but its not throw away or run away.