440 or 540

achamb · Post by **achamb** » Fri Feb 08, 2008 9:46 pm

Here is a question for anyone.
Are the 440 and 540 cyc. and Pistons interchangeable with each other? And what is the difference between the crank cases? The bearings have different numbers on the yamaha website.

Thanks Andy

srxvmax50 · Post by **srxvmax50** » Mon Feb 11, 2008 8:12 pm

Anybody want to take this one on? I'm not up on it enough in order to help our friend out. Or is it just a whackeddy question from an otherwise nice person? Someone please? MJD.

achamb · Post by **achamb** » Mon Feb 11, 2008 9:52 pm

The reason I ask is I have a 540 available. And I was told the 540 had a better bottom end. When I was looking on the Yamaha Parts site I saw the crankcase numbers ( SRX 8m6-15100-00-00, Vmax 8U9 15100-00-00) seemed very close. Just trying to go in the right direction for a good runner,

Thanks

jipcee · Post by **jipcee** » Tue Feb 12, 2008 12:10 am

I'll try but, oplsed can probably give you the complete rundown.
Of course 440 piston are different than 540 piston.
You can use 540 cylinders on a 81 srx 440 bottom end.
Seems I have read that the 540 crank is better than the 440.
Since you can use the 440 bottom with 540 jugs, I would assume the reverse would also work i.e. 81 440 jugs on a 540 bottom end. (Not too sure of this one.)
We have used 440 bottom with 540 top and it seem to loose a little performance, maybe the 540 bottom is stuffed a little tighter than the 440.

I hope this helps a little, but, like I said "opsled" seems to really know his stuff.
Perhaps he could shed some more light on subject.