91 Bayou 220 won't start

[paintslinga2010]

Update. I took off the old timing chain only to find the pin on the cam sprocket sheared off. So now to fix this problem. I guess first I need to know what would cause it to shear? Valves hit the head? Im not sure how to get the pin out. I fear I may just have to pull the head.

 

['00 WO-YA!]

You're pretty close man, go ahead & rip it off, you're better off to know than not to know.

 

[paintslinga2010]

Ripped the head off and pulled the valve covers to find.. a broken intake valve tappet. The part that rides the cam is broken clean off. I have no idea what would cause this. The piston looks fine just very black. It looks like the problem area is the head. What would my next step be? Take the head to someone else? lol I'm willing to give rebuilding the head a shot. I'm just not sure what is involved.

 

[paintslinga2010]

I looked closer and found evidence of the valve contacting the piston. It looks slight but must have been enough to cause damage.

 

[MotoArts]

Tappet, as in the rocker arm itself broke in half?
Check the cam lobes and pads on the rockers for evidence of overheating (blued or brown colored metal). May have a top end lubrication problem that might cause the rocker shaft to seize, or valve to seize in the guide.
My Warrior did, and was caused by a simple lack of oil change plugging the filter...completely...

 

[paintslinga2010]

The oil was very thin when i drained it. Almost like it had gas in it. So lubrication could definitely be an issue. But there is also evidence of the valve contacting the head. Next i am going to try to remove the rockers and valves to check them.

 

[MotoArts]

Need a rocker shaft puller, or need to make one.
Will need to compress the valve springs to get the spring locks/retainers out first though.

If it just kissed the carbon on the piston, you may be ok with a new valve. Check for bent valve by pouring some liquid (soapy water, WD40, etc.) in the port and see if it leaks into the chamber. Any leaking at all is not acceptable.

Or just send the whole deal to Midway and have him port and overhaul it...

 

[paintslinga2010]

I think I found the final broken part hopefully. The intake valve is bent. I got the keepers off and the valve didn't come out easily which makes me think it was stuck and broke the rocker. I've never been this far into a head. I can't just start replacing parts can I? Do I have to get a valve job or something like that?

 

['00 WO-YA!]

If ya have the cash to spend a good valve job would be ideal. Sometimes people can get by with replacing a valve & hand lapping it in with some valve grinding compound. If you're trying to do this on the cheap you can give it a shot. Ya might even try checking ebay for a good used head man, especially if you're gonna need the rocker too.

 

[paintslinga2010]

After pricing all the parts it looks like an ebay head would be a cheaper easier route.

 

['00 WO-YA!]

As long as you make sure to get a good one it'll be a much simpler solution.

 

[paintslinga2010]

Can I re-use the head gasket or are these one time use?

 

[elwood]

buy a new head gasket

 

['00 WO-YA!]

Man, I honestly have reused em but I'm not going to tell you it's ok. I can't see the condition of yours & I'm honestly not certain what type you have.

 

[MotoArts]

Buy the proper, complete, top end kit.
Period.
There are o-rings and other shizz in there too.

You can get away with reusing solid copper head gaskets (ie. on a 2 stroke) but why risk it on anything else?