80 gs550l catches when cranked by hand

[ChicagoRob]

Hello.

I'm trying to do a valve shim adjustment, but noticed something funny.

When I turn the engine over clockwise, there is a catch every 180 degrees. There's a "thunk" type noise, then I have to give it a bit of force to get it over that spot, then the same thing at another 180 degrees.

Counter-clockwise is smooth all the way around.

Any ideas?

Thanks,

Rob

[ChicagoRob]

80 gs550l catches when cranked by hand - Bump

I forgot to mention that this is with the plugs out and in neutral.

Any ideas on what to start testing would be greatly appreciated.

Rob

[ChicagoRob]

Solved - Bad Timing

When I was setting the valves, I had the Cam tensioner off. (Bad gasket) I must have let the cam chain skip a few teeth.

Rob

[SqDancerLynn1]

that will do it, probably piston hitting a valve