Topic: 77 550 engine in a 72 500 frame...sprocket question

[neil young]

alright it's time for new sprockets and chain.
will it make much of a difference on what i need to purchase seeing as the frame is a 500 and the engine is a 550?
or are they similar.as in spacing,# of teeth etc etc.

[FunJimmy]

Should all be the same. Get a chain with extra links and cut to length.
Remember, O-ring chains will hit the case, cutting through the alloy unless
you machine the front sprocket and space it out approx 0.100"

[TwoTired]

The 500 has a 34 tooth rear sprocket, and the 550 uses a 37 tooth sprocket.  Both use 17 T fronts.  I think the primary chain sprockets inside the motor have a different ratio to go along with the rear sprocket changes.  It's in the shop manual somewhere if you want to look it up.

Were it me, I'd use the 37 T rear for a 550 engine.
  Avoid O ring chains unless you also do a 520 conversion along with new matching sprockets.  Those are narrow enough to clear engine cases.

Cheers,