What have I done???

[railroad]

To stop a oil leak I changed the valve cover gasked and chail tensioner o-ring. When I went to start the bike ( 1980 XS11G) it fired but didn't catch. That was the last time it even poped. It's got spark, is getting fuel, air cleaner is clean. I've tried starting fluid both in the air cleaner and directly in the cylinders, Nothing, not even a pop uther than a rather impressive backfire through the carb. It seems like a timing problem to me, But how?? Could it have changed when I changed the o-ring?? the chain has streched a lot (no zip noise when you adjust it) The odometer reads 68,000 miles (i have no idea if it's the 1st, 2nd, or 3rd time around the clock). This is the bike i bought for $200 from the Salvation Army and my friends say junk it but as many of you seem to have with yours, I have kind of fallin in love with the beast and want to keep her running. Any Ideas?? Anyone know of a good Mechanic in the San Diego, or Southern California area???
THANKS

[skids]

If you feel brave, check compression. You may have slipped the chain on a cam sprocket. You risk bending a valve, but I suspect that if that is the case, the damage is already done. Did you roll the bike in gear, or force rotation of the rear tire while the tensioner was off? I think that even a sticky clutch could move the chain if the rear wheel rotates.

[railroad]

No, I didn't roll the bike it was on the center stand

[trbig]

I'm assuming you took the tensioner completely out for this. Was it done correctly with the timing mark on the "C"? Did you install the tensioner, loosen the bolt and let it contact the guide, then torque the bolt and nut? If you did all this, is there any possibility that you stripped the bolt?

It all sounds to me like what they are saying. It seems to have jumped time somehow. Only way to check is with valve cover back on, and check the marks on the cam gears to your crank timing mark. You can also check to see if you have compression as stated. If you have already cranked on it, I suspect the damage is done already. You could possibly luck out if it has only skipped one or two teeth.. that's why I would check the timing before I cranked on it any more. If it has only skipped a couple .. it may skip more and do more damage if it hasn't already.

Tod