Reliability of the VMAX 540
Since the 540’s reliability is often disputed I figured I'd put my 2 cents in the hat! The 540 when properly tuned can still today, give sleds in its class a good run. How can that be almost 20 years have gone by? The industry had moved away from the large c.c. 3 & 4 cylinder engines of the early 70’s Yamaha (like most competitive brands) were now producing relatively small c.c., high compression high revving motors to provide enough arm stretching torque for acceleration and H.p. to reach speeds unheard of before this period. Mercury Snow twisters, Rupp Nitros, Yamaha Srxs, and later Polaris’s little liquid cooled barn storming 340s were other examples of this period! Vibration, clutch failures, piston failures, blown cranks, and head gaskets problems were common. Long term reliability was sacrificed and almost unheard of during this period!
Yamaha learning from their experience with the Srx’s and especially the 82 500 produced the 540 and increased it’s displacement, lowered the compression and r.p.m.’s then added a main bearing along with the addition of round slide carbs increased reliability. The 540s engine was smooth, powerful and reliable especially, if in capable hands when modifications were performed. The 540 was top dog at Yamaha for many years (until 91 in Canada) and therefore was placed against 600 & 650 triple Indy’s and 650 and later 700 Cats. Keep in mind, Stock main jets were 320’s in the 83 V-max and Yamaha bulletins kept lowering them until settling on 290’s in 1984.
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, and an eye on the jetting and compression and the 540 engines can provide many miles and thrills! Later V-max 540.