VintageVmax.com

Cool!! Thanks fer posting.

I have one of those jackshafts and secondarys. Like to try it someday just never get the time. Something always seems to come up.

opsled

Does any one have there old clutch spec or 44 Carb set up they use to sell it would be nice to have all the testing they did 30years ago before its lost forever.

slowpro wrote:Does any one have there old clutch spec or 44 Carb set up they use to sell it would be nice to have all the testing they did 30years ago before its lost forever.

http://www.vintagevmax.com/86porting.htm
Regarding the carburetion on the update port V-Max, the stock 38mm carbs are all the engine requires. Larger carbs will not increase airflow or horsepower on this engine. This is similar to a Wildcat, which developed the same airflow and horsepower with either 38mm, 40mm, or 44mm carbs.
http://www.vintagevmax.com/article_index.htm

How about the 81 srx 440 with 44 and why did bender put 44 on his 540 s if there was no power gain. I am looking for a base line set up for a 81 440 with 40mm carbs and there specs for a Polaris wide belt overdrive setup Richards perfomance sold back in day I trying to set a 81 srx for speed runs only just though this info would be useful thanks ken

slowpro wrote:How about the 81 srx 440 with 44 and why did bender put 44 on his 540 s if there was no power gain. I am looking for a base line set up for a 81 440 with 40mm carbs and there specs for a Polaris wide belt overdrive setup Richards perfomance sold back in day I trying to set a 81 srx for speed runs only just though this info would be useful thanks ken

Bender ran 44's cuz he's an idiot (lol).

I dono, I'd have to look back at those dyno sheets to even guess but I think those were done on basicly stock engines or with the updated porting specs. Bender, Delaughter and many others have taken this engine to further hights. I'm sure that depending on what was done there becomes a point where bigger carbs will make a difference.

In comparison I was just at Olaf Aaens a few weeks back watching him dyno an 800 Vmax-4 mod for a friend of mine. this engine had custom 65mm roundslides on it and the engine has a 65mm bore. It was 40 degrees that day and the carbs had #640 mains in them. It produced and uncorrected 225hp at 12,500 rpm (crank speed). The plugs were all a light tan.

To pull air through a carb that big with a piston that size and mains that large is one thing. To produce that kind of uncorrected HP and still be close to lean at that temp is another. That 800 was about as efficient as you can get for pumping air in and out. Quite a sight to see.

I'm sure the 540 can be built to use 44's (or more).

opsled

I was going to convert my 81 to 38 mikunis that I have from a 540 are the butterfly carbs on my 440 38 mm or 40 mm im wondering why their offering 44 versus 38's seems like alot carb for a 440 that u r gonna ride and and not just dragrace (any thoughts or input ?)

Phil, ever converse with Olav on his artical awhile back on taper bore carbs? I think it was Am Snow unless he writes for someone else also.
I did a set of 38's for my SRV. The concept is the taper boring gains velocity through the center of the carb. WOT isn't really my goal anymore, but I do like midrange punch and throtle responce. Big sled engines are two big for our dyno and I never have taken out to Perry's, but ya, I think I liked it
I also bought some bar stock to make up a set of those UFO deals but of course haven't got to that yet, on paper, makes sence to me.
I agree that a well built 540 will like 44's or maybe more but I also believe sometimes velocity is more then volume.
Last year the kid had to do some straightline testing on a 600 open engine. Oval rules require stock, untouched 34 mm carbs. Regan has driven some pretty fast shit, no doubt that bigger carbs would out power those 34's after several hundred feet, but he swears nothing he has driven has left that hard. I kinda learned that the first time I put a tunnel ram on a 327 small block in a street car back in the early 70, I did look cool tho........

No Bob I've never talked to Olaf on that. I'm sure it works though.

I was being somewhat sarcastic in my last post (I have an issue there lol) but the basic premis is that bigger carbs will make an improvement on almost any engine if the work is done to allow it. On a stock 540 there is no need for them. Yamaha sized them well and got the pipes tuned about perfect to boot for what the engine was intended to do. In mod form at higher than stock rpms???? Probably a different story depending on what has been done.

I know there are 540's out there that make more hp with bigger carbs and non stock pipes but they are not the average like was used in the dyno runs done on pipe shootouts of the past.

opsled

BENDER USED .44 ON THE 81 SRX BECAUSE THE MOTOR HAD THE PORTING TO TAKE IT. THAT SLED LIKE ALL THE SRX,s WAS UNCARBERATED SO IT COULD BU USED FOR TRAIL RIDING. 3:16 (yammie tony)

somebody NEEDS to repost these pics^^^^

http://s308.photobucket.com/user/Vmax54 ... t=3&page=1
http://s308.photobucket.com/user/Vmax54 ... t=3&page=1

Chuck to the rescue

I’d kill for the Vmax dyno tune kit specs. It was the best $100 I ever spent back in 1995.

The update porting specs are on the Homepage under Article.