Interchanging motor parts

[Hawkeye]

I have a tech question for you guys.
Will the 79 jugs and heads fit on a 73 motor? I know the piston pins are different.but that is all I know about the difference in motors

 

[TwoManyXS1Bs]

Supposedly, cylinders and heads from 1972 to 1983 should all interchange. Not sure about the older camchain tensioner. You'll want to check that your '73 type-B tensioner fits cleanly into your '79 cylinder, with unrestricted range of motion for its tensioner arm.

http://www.xs650.com/threads/cam-chain-tensioners.1056/

 

[5twins]

If it doesn't, you can probably use the later tensioner assembly and the later rear tensioner blade.

 

[gggGary]

Either the cam has to be from the 73 which uses 17 34 sprockets and a different chain pitch or the crank and cam and chain need to be from a 447 - 18 36 sprockets, which isn't a bad idea..... you could then use 447 small wrist pin pistons on the stronger late model rods. When pushed really hard and fast things happen, even to 447 rods.
From a recent facebook racing group post;

Ran the next race in the 350 class.

 

[TwoManyXS1Bs]

Nice one, Gary. I just love engine cutaways.
Saved a copy.

A good argument for long rods...