VintageVmax.com

Tony, this is from the ARTICLES section and something I wrote years ago.

" V-max owners normally did not want beat by the competition on the trail or lakes and I believe most 540 owners assumed the 290’s were 2-3 sizes fat and dropped them down regardless of their altitude or temperature. In the many 540s I have bought (most seized) I find jetting around 280-260's and one with 230s!!! This is on top of removed or gutted air boxes and some with porting done by "Uncle Bob"!?! Keep the air box stock, an eye on the jetting along with the compression and the 540 engines can provide many miles and thrills !"

You also, have to remember this was Yamaha's top dog until the Vmax4 was released in 1992 and most of these sleds have been tweeked and abused.

My son really wants to keep it so I guess Ill hunt for parts now and hopefully by nextweek can get everything together oand ordered I also have to find guages as the speedo is stuck at I believe 60 and the tack does not work either but I will say that for not getting onto the gas on this thing due to breaking it in she had some snap low end was there but the midrange was outstanding you could just feel it wanted to just cut loose and sing but again we needed to be nice to it until it was broken in and we were so close!!

So these called stock for 290's on the main jets?

Firstly, was your airbox on tight and secure?? As Bob said a leaking intake boot?? Dirty carb that leaned out?? Check the jets?? Were the carbs cleaned out yet this year?? (as mine have been cleaned out 3 times this year). These are not machines that you just start up and ride in my opinion, they need to be gone over and maintained. They are a consumer sled but are high performance machines that have to be tweaked as per temperate condition changes such as drastic temperature change. I learned my lesson last year.

TonyV wrote:So these called stock for 290's on the main jets?

Yes, and as you have read Yamaha started out with 320's and in fact already had the jetting cleaned up by going all the way down to 290's.