Big problems.

[Yamafreak]

So my 88 is sick. I went from no lid to a clamp on filter. And she wouldn't run so I went to basic carb tuning and she started and ran. So I burbed the gas and she went snap, followed by a big rattle and died. I'm thinking broken timing chain and /or valve. It's not seized and pulls smoothly. But she won't start. Idk. Ideas

 

[Warrior1996]

Possibly sheared the keyway for the flywheel. Check to see if your flywheel spins when you turn the motor over...

 

[Yamafreak]

I felt the motor open the exhaust valve because I have a pull start. I didn't feel the intake open up but I did pull quick enough to pass that. I hear compression. I know I have alot of testing to go thru.

 

[Yamafreak]

I will say if I have to do the valves. I will tear the motor apart and rebuild it. New everything on a 30 year old machine will not hurt one bit.

 

[Warrior1996]

I would see what in the valve train is moving, and start there. Sounds like you'll be tearing it apart to find the issue