85 Honda Big Red

[rockman20]

Okay, this is my first post here.

I recently did a top end rebuild on my 250 Big Red. I burnt the exhaust valve pretty bad. I put new rings in and had the intake seat cleaned up and matched with the valve and then a new exhaust valve and seat.

I put it all together and it starts beautifully! Makes me think that the exhaust was burnt from new because it has never started this nicely! However, it has kind of a knock of sorts. It's tough to explain. It gets worse and louder when under power.

I am thinking that I got my timing off a bit. If I take the bolt off from the cam chain tensionisor and I turn the screw inside, the knock disappears. However, as soon as I let go of the screw driver and it adjusts itself back to where it wants to be, it is back.

What do you guys think? Does this sound like I may be a tooth off on the timing? I tried my hardest to make sure that I was dead on, but I guess I may of missed. I really don't want to take the engine back out to fix this if this is the problem. Any tricks?

Thanks in advance!!!!!

[Hair Bear Bunch]

Hi, and welcome aboard.
Could be the timing chain has streched and you've run out of adjustment. Mine has a tinny sort of knock/rattle and I'm pretty sure thats the problem but I use it too much to put it in dock and investigate.
Oh, and don't forget pics, either here or in the working BigRed thread!
Rob.