Are all jugs the same between 72 and 76. Should I use my 72 stuff.

I know the heads and cams are different. 72's being more desirable. But what about the cylinders. Are there any differences being cosmetic or other wise.

I'm putting in a 76 motor in my 72 bike. It needs a damn base gasket so it all has to come apart. So I thought while I was waiting on tax money, I might clean up the 72 stuff and get it ready to bolt on.

As I'm typing this I think I recall the cam chain won't work out for me. Is that correct.

So can I use the jugs and the head. And maybe the cam or is it a no go on the cam. Thanks

Early motors (XS1-TX650) used 17 tooth crank sprockets with 34 tooth cam sprockets, and late motors (TX650A-end of production) used 18T at the crank and 36 at the camshaft, and the pitch of the cam chains also changed at that time. Your early cam can't be used on a late low end unless you install a 36T sprocket and degree it in. In 1972 (XS2) the gasket surfaces on jugs and head were changed; these parts can mix and match with later motors without a problem.

Heads up on the early cylinders with the inner web. These really shouldn't use the later tensioner, not enuff room in the camchain tunnel. They must use the earlier sprocketed tensioner, which requires the earlier '256' 8mm camchain. Have to kinda plan-out the mix/match here. Here's a recent thread:

http://www.xs650.com/forum/showthread.php?t=38674

Thanks guys'.

Looks like I'll be keeping the 76 jugs.

Would you recommend using the 72 head.

Cal, if you'll go to www.biker.net and look at the part numbers, you'll find answers to many of your questions. The head and cylinders on your 306 engine (XS2 and TX650) are the same ones used in the later 447 engines (1974 and forward) with the exception of the black finish on the barrels and rocker box on some late versions. My recommendation would be to pick the head with the best valves and tightest guides.

grizld1 said:

Cal, if you'll go to www.biker.net and look at the part numbers, you'll find answers to many of your questions. The head and cylinders on your 306 engine (XS2 and TX650) are the same ones used in the later 447 engines (1974 and forward) with the exception of the black finish on the barrels and rocker box on some late versions. My recommendation would be to pick the head with the best valves and tightest guides.

Click to expand...

I'll check everything out.

I'm hoping the 72 is better. I know it only has 5xxx miles on it. The 76 motor is unknown mileage.

Just have to tear into them to find out whats what I guess. Thanks