vmax 540 big bore questions

S

sxr1000

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Ayone know anything about the big bore kits that were offerd back in the day for the vmax 540? I have sleeved cylinders and would like to build one but I am haveing problems finding pistons,did they use cat or polaris or some one of a kind? anyone know? thanks.
 
BIG BORE KITS WERE VERY POPULAR FOR VMAX 540. I BELIEVE AAEN PERFORMANCE, BENDER RACING, DeLAUGHTER RACING etc ALL HAD THEM. I WOULD HAVE TO DIG IN OLD CATALOGS BUT I THINK THESE KITS WERE 600cc plus. I ALSO THINK WIESCO MADE THE PISTONS. 3:16 (yammie tony)
 
Starting line products also had the 600 cc big bore engines , they said that they had 103HP and tons of torque. I believe that they had 77 or 77.25 mm pistons in them. Wiseco can make pistons for them but you will pay dearly for them and you will need oversize sleeves for them as the standard sleeve is not large enough to except that large of an overbore LA sleeve will custom make them for you and they aren't that much more then standard sleeves.

:2strokes: :2strokes:
 
I had a line on a NOS big bore kit this fall, but never could put the deal together. I have asked many yamaha guys about them and no one seems to give me a straight answer. Pistons would be a major pain to locate

Monty
 
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So far pistons have been a pain, my machinest says 76.5 mm is the the max on the cylinders I have, arctic t cat 900? it all depends on the center of the wrist pin to the top of the piston but I can not find anyone with a used piston who will measure one and let me know.
 
I think SXR1000 is talking about the THUNDER CAT 900cc. that is 76.5 mm in diameter. Polaris 600 cc power valve engine is 77.25 mm but I am not shure what the pin height is ,they both have 20 mm pin diameters.
 
Well so far I can not find a piston that will work, the thundercat piston is about an 1/8 inch short and the ring pins are in the wrong spots,I need to find a polaris sl 900 watercraft piston and measure that,I have contacted all the companys that made and sold these kits and it is like there memory has been erased!,even bender claims to not know anything about these kits,I will keep searching.
 
I dont know if this would help you but a friend of mine prostockbob had one.It was done by Dave D.@ around 1984.He said something on the line that the pistons were made by Venolia,they make car pistons..I'll dig some more for ya to see if he had any notes..
 
I'll talk to my friend tomorrow..I know he also 44mm roundslides on it also..
 
Well I found out that slp had there pistons made in England by someone? all the other companys used wiesco.
 
Stock HP on 540??

Kind of hijacking this thread a bit, what was stock HP on the 83 540??

How dependable was this motor?

Curious as to whether this would be a good motor to use in another chassis?

Have a line on a 83 for $200. Based on pics, its dirty, seat is bad, decals faded etc. & owner says no spark.
Hmmmm??

Any input here is appreciated.
Thanks Rob
 
Terry Paine from Bender had his ported, stock carbs Vmax at dyno-tech.
HP @ RPM
89.9 @ 8250 stock pipes
95.8 @ 8500 stock pipes, gut air box
89.6 @ 9000 PSI twins, gut air box
84.8 @ 9000 Aaen twins, gut air box
92.7 @ 9000 stock pipes cut to FIII spec per Yam
 
I have all the late 80's to mid 90's Dyno-Tech articles and I talked to them 10 years ago to ask permission to reprint the 540 charts for my web site. General concensus is to stay with the stock pipes ! ie "95.8 @ 8500 stock pipes, gut air box"
 
the 540 big bore that i had was 77mm bore . it was built by toas cycle in utah. there piston # was 111873/372 . that's what is on the box . I have a used piston without the ring if interested. 610cc was the engine size.
 
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