Well, actually yamaha did produce a SRX500 in '82. They found crank problems and recalled them just prior to hitting the dealer floors. So far there are about 9 located still around in private collections:
Here is an article taken form Vintagevmax.com
What Happened to the...
82 VMX 500 F??
Well.. Here's your answer...And Heres a Picture
**The following article was taken from the Fall 1982 issue of ?Snowmobiler?s Race & Rally? (Now known as Snow Tech Magazine.)
The SRX of ?81 and the VMAX of ?82 were machines of which Yamaha wasn't?t exactly proud. Rather than just ignoring the problem, Yamaha never has released the last year?s VMAX, and has offered excellent terms for trading in the ?81?s. An interview with Tom Berkley, Assistant Product Manager- Snowmobiles, examines the situation and what was done about it.
R&R: Tom over the years there have been several different sleds that have been referred to as ?Lake Rockets??the SRX being one of them. Where did this concept come from?
BERKLEY: Well, it isn?t too difficult to trace back. When most of the manufacturers were involved in oval racing, they were all developing small, lightweight, very fast sleds. The fact that these sleds were close to 768 db made them very interesting machines. A few drivers converted them into trail sleds and started this thing called ?lake racing? which actually had been going on all the time anyway.
But when oval track racing began to decline, manufactures discovered there was still quite a market for these machines as super, hot trail sleds, or ?lake Rockets,? if you prefer.
R&R: The 1981 SRX was promoted as being ?lean, mean, black, and evil.? How would you describe this machine?
BERKLEY: The 1981 SRX was designed for lake racing. It had a lot of horsepower for a 440, with the capability of going very fast. It wasn?t unusual for us to see one in a radar gun going over 100 mph. It was a machine of very good acceleration and top speed. It had a good suspension and other features along with its radically new styling. The thing we learned form the ?81 SRX is that there certainly is a demand for a high performance machine, but they should also be a good trail machine. Of the people who but this machine very few are interested in only lake racing. Most of these people are interested in general snowmobiling.
R&R: Do many people buy them as status symbols?
BERKLEY: Of course there are some who would buy them for that reason, but the demand is good for low end torque, excellent mid range performance, and smooth clutching-- so the machine can be ridden on the trails.
R&R: What were the changes made from the ?81 SRX to the ?82 VMAX?
BERKLEY: The primary change was to increase the displacement from 440cc to 500cc to maintain a high level of horsepower. This gave the machine more horsepower at engagement rpm and at mid- range.
R&R: Where did the problems develop which were serious enough that the ?82 VMAX was never delivered to the dealers?
BERKLEY: First, we didn?t think the ?82 was significantly better than the ?81 in terms the average customer was looking for. It didn?t meet our expectations for overall ?trailability?
R&R: What about the rumor that carburetion was very critical and required more than normal adjustment?
BERKLEY: It wasn?t just a rumor. It was true. Machines like the SRX, with radical porting and carbs to match, have a tendency to be very sensitive to carburetion. They require frequent adjustment to suit the temperature and the altitude.
R&R: What type of carb were you working with?
BERKLEY: It had a butterfly carb with many different circuits to suit various throttle and rpm settings. Its general function was O.K., but it was difficult to adjust.
R&R: Would you have been better of with a slide valve?
BERKLEY: The ?83 VMAX does have a slide valve carb. And yes, it is easier to tune. But the biggest thing is the fuel requirement of the engine. No matter which carb you use, the engine has a certain fuel requirement.
R&R: It takes a lot of fuel, is that what your saying?
BERKLEY: No, not necessarily. The SRX has a rather narrow tolerance for fuel mixture. So, if you went a few sizes too rich, it was really rich. If you go a size on the lean side?it seizes. That is a narrow fuel tolerance. It was an intolerant engine? fuel wise. And this is a carryover from the old oval track racing days.
R&R: Through the excellent promotion on the ?82 VMAX, there must have been money paid down to the dealers to reserve a sled. Wasn?t it tempting to release it anyway?
BERKLEY: Yes, the demand was certainly there, and the lake racers would have been very happy with the machine. A lot of dealers did have machines committed to their customers. But for the majority of the customers we did the right thing. It was very gratifying when our customers and dealers agreed with our decision not to release the sled. We did not receive very much static at all about that decision. I think our customers and dealers (if not the snowmobile press in every case) realize the market is evolving. Sure they want good acceleration and good top speed, but they also want a good all- around snowmobile.
R&R: A total performance snowmobile?
BERKLEY: Right! A true high performance snowmobile should perform very well in many different areas. It should not only go fast, but should handle and ride well, start easily, and go in deep snow. A big part of the high performance market is in the mountains. Mountain riding requires a machine with a wide fuel tolerance to fuel mixture. It requires good low end and horsepower, smooth clutching, and the capability to go in deep snow. This was also a consideration on our decision not to release the ?82 VMAX.
R&R: What was done with these machines and where are they now?
BERKLEY: Almost all of the ?82 VMAX sleds are still being housed. We have not yet decided what to do with them. We did use some in our distributor racing program in Alaska?which is a series of about five or six races, anywhere in length from about 100 miles to 600 miles. Tim bender of Aaen Performance won three races with one. It was actually a very good machine and very reliable?in the right hands.
R&R: What is your program for the ?81 SRX?s?
BERKLEY: We value our high performance customers, because we realize that the people who buy the SRV?s and the SRX?s are interested in and have the capability of buying a new machine every year. Usually the influence the purchase of many more snowmobiles. They are usually the leader of their clubs or their family groups. So, the owners of the ?81 SRX?s were offered to make an excellent trade- in deal on a new VMAX 540 or a new SRV.
