Vmax 4 750 and 800 case differences

fngboy

fngboy

New member
I have a case for a 750 and a complete 800 motor. I have been told that the cases are different. As I look at the two they look the same. I checked the microfisch it is the same picture. Can someone tell me the differences in the cases? It has to be internal. The 750 is a 94 and the 800 is a 95.

http://cgi.ebay.com/ebaymotors/yamaha-VMAX-4-crank-case-assembly-750-800_W0QQcmdZViewItemQQcategoryZ100456QQihZ011QQitemZ320096579331QQrdZ1


http://cgi.ebay.com/ebaymotors/yamaha-VMAX-4-800-snowmobile-motor-engine-4-cylinder_W0QQcmdZViewItemQQcategoryZ100456QQihZ011QQitemZ320098660492QQrdZ1

thanks :drink1:
 

FIRST YAMAHA MADE HUGE CHANGES TO THE CRANKSHAFTS. UPPER AND LOWER CONECTING RODS WERE LARGER ON 800 THAN 750. CENTER CASE DRIVE GEARS WERE ALSO LARGER WITH DUAL GEARS. PTO GEAR WAS ALSO LARGER. EVERYTHING I HAVE ON THESE SLEDS, SHOW THE VMAX 800 CRANKSHAFT WILL NOT FIT THE 750 CRANKCASE. JUST TO DOUBLE CHECK, I WENT BACK INTO PER 1995 YAMAHA TECH MANUAL. 3:16 (yammie tony)
 
thats what I needed to know

Thanks alot. I am selling that stuff on ebay and I had 2 people tell me that they were different but when I asked how they are different no one responded. The only thing I can do is look at the cases and check the microfisch. The 750 is totally taken apart but I want to leave the 800 together. This 750 was big bored and the crank was set for 180 degrees. I don't have any idea what other thing were done to it but inside the case looks stock.

thanks
 
750 pistons

The motor was in pieces when I got it. it was missing a cylinders and head. the other 2 pistons were melted. I think someone went a little lean with their jetting. At anyrate it had a Wisco piston in it and a yamaha piston from a dirt bike or something. It had a bigger bore than an 800.

I sold the cylinders and the head on ebay.

thanks
 
Thats what I run.They are 471M06800.They are for DT/MX 175 as well as tri-moto 175.I was thinking, even stock size 66mm mx pistons would be a good upgrade in a 750 [63mm] for guys who like OEM yammy pistons, that dont like pin adapters from Hauck.The compression height on mx pistons is @.030 shorter than original 750 ones, sort of a built in cylinder lift.Just have to deck jugs for correct squish.Anybody else use these slugs before.
 
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