I did not mix up the cams

[olebiker]

I stated in another thread that after reassembling the beast (bent valves and I decided to replace my clutch and cam chain). I got it together and had a very fast turning engine with no compression at all. I knew that everything had gone together right and thought that perhaps I mixed the cams up. Well today when I pulled the valve cover and hit the starter, crank turns with no movement of cams and chain. Doing the rebuild I did roll the engine manually twice to check that all marks were lined up as it says in the manual. Everything was fine. Somehow the cam chain must have been riding on its edge. I pulled the head after checking compression with the finger method. Seems like I have a bent valve on number 3 cylinder. Same as when I started all this. It is hard to believe that the cams would go around twice by hand and then as soon as I hit the starter poof off the sprocket. I did get the chain hooked on the sprocket and tried by hand to make it jump so I think the sprocket is ok. At first I thought it must be toast but that seems unlikely. What an exercise in frustration this is turning out to be.

[Ken Talbot]

Re: I did not mix up the cams

Originally posted by olebiker
It is hard to believe that the cams would go around twice by hand and then as soon as I hit the starter poof off the sprocket. I did get the chain hooked on the sprocket and tried by hand to make it jump so I think the sprocket is ok.

That's because there is a 99.9% chance the chain was not on the sprocket. Rather, it was wedged next to the sprocket. Turning it over by hand won't make it slip, but turning it with the starter will make it slip in a heartbeat. You're not the first person to do this. You're not even the first person to do this in the past week.

Sorry...

[olebiker]

That's ok but how on earth do you keep this from happening?

[Ken Talbot]

- do this with the bike on the centrestand so the chain hangs vertically
- use a good flashlight to look down and verify that the chain is in fact on the sprocket
- once you know it is on the sprocket, wire both sides so there is absolutely no way it can go slack while you proceed with the assembly
- pray to the XS gods, and maybe sacrifice a virgin for good measure

[olebiker]

Originally posted by Ken Talbot
- do this with the bike on the centrestand so the chain hangs vertically
- use a good flashlight to look down and verify that the chain is in fact on the sprocket
- once you know it is on the sprocket, wire both sides so there is absolutely no way it can go slack while you proceed with the assembly
- pray to the XS gods, and maybe sacrifice a virgin for good measure

**** I am in trouble. Where do I find a virgin?

[planedick]

Easy

Look for an ugly 6th grader...

[olebiker]

Hole jees no I am in Canada. They don't make it to that age.

[skids]

I bought a head from ebay once that had a mismatched valve in it. The length to the keeper notch was just a little "off". The valve had no resulting compression.

[Ken Talbot]

Originally posted by olebiker


**** I am in trouble. Where do I find a virgin?

I never said it would be easy!

[olebiker]

Oh well I now have lots of valves. Two heads. Hopefully I will be able to use one from the old head and just lap it in. Set the shims and try again. I will reuse that head gasket as it didn't run should be ok. I used pam on all the gaskets except the head gasket. It came apart ok though.

[gene]

Manual Compression Check

Not sure exactly how. Can I check compression and get accurate results by hand. I have the motor on a stand and want to know if I should take the motor down or not. Cams look really good, hate to pull the head off for nothing.

[olebiker]

Not sure exactly how. Can I check compression and get accurate results by hand. I have the motor on a stand and want to know if I should take the motor down or not. Cams look really good, hate to pull the head off for nothing.

I don't know how you could turn it over fast enough. Maybe one of the other guys has done this.

[Ken Talbot]

With it all assembled, you could do a leak down test. The motor does not spin over for this. Not quite the same as a compression test, but it can tell you a lot of other things about your motor.