April 23, 2008
SRX Development Story
SRX Development Story: Part 1
I’ll preface the following by saying I’m splitting this development story into several installments. I have dug up quite a few related documents and will scan them then scatter amongst the pages to add some funk. For example here’s a little history for you- history-remaster.pdf– I am relying on memory here and apologize if some things don’t ‘gist’ 100% with your own recollection. I’d be happy to post your comments or any additional information. I hope you enjoy the read as much as I am enjoying the writing. It’s stirring up a lot of old memories for me.
Before I get into the nuts and bolts, I think it’s important to remember where we were living back in 95/96. We had been a good two years in developing our light-weight Pro-Action leading arm chassis (code name OMD) and new 3 cylinder, single pipe engine. Ole Hayata, was head of engineering and had done an amazing job to deliver us nine new models in the die-cast, chassis platform, in time for the 97 model year. It was during this same time period, our competitors took their next step in sled evolution with the release of the 600 triple / triples -three cylinder-three pipe rockets- based largely on ISR Formula 3 racings, popularity of the day. The F111 Skidoo, ZRT 600 Cat and XCR600SP Polaris set a new benchmark for displacement performance and were gunning for top speed honors against the bigger sleds of the day.
Apparently we needed a triple-triple, 600 version of our new SX. And so it was we set out for Japan to convince engineering to shoehorn some pipes into a sleeved down package. Well it didn’t take very long to discover the SX 700 engine would not survive our bench tests using triple pipes. Further more the body shape and die-cast bulkhead sub-frame of the OMD did not allow the required clearance for proper air management and cooling, given the real estate required for the tangle of pipes. It could not be done. I clearly remember my old friend Gary from Prince George Yamaha calling me shortly after the release of the SX 700 to quiz me about triple pipes before he took on the Canadian distribution of one of the leading after market exhaust brands.
‘Don’t do it’, I advised, ‘The engine will grenade. If you push it, the crank won’t live…’ Man- was that bad advice, but as it turned out Gary didn’t listen to me and went on to help modify hundreds of 700 triples in mountain chassis with many running reliably to this day.
We did our homework with YMC and decided our next machine would have an all new 600cc 3 into 3 engine. It was also decided to build a 700 variation for a no holds barred assault on the muscle sled segment. The Vmax4 engine was stuck with a TSS chassis and had been max’d out at 800cc (small pun intended). We set the target for OMH to be the lightest (500lbs), fastest top speed and quickest accelerating muscle sled on the market. We had witnessed the 500 class (representing the greatest sales volumes), evolve into the 600’s and it didn’t take a duck hunter to figure out the 700 class was where we should be aiming.
A bright young engineer (and notorious after-hours disturber) was given his first kick at ‘project leader’. The parting gift of Mr. Hayata who was moving on from snowmobile group to motorcycle development came in the form of Masayasu Saito. Masa-san understood very well the competitive mentality as well as the snowmobile lifestyle. When he was a young buck, he purchased a Phazer in Japan and traveled north every weekend to ride it (and chase girls). I had known him for many years as a field testing engineer and durability rider previous to that. He was a great choice to head up the OMH project which would eventually come to market in 1998 as the SRX 600 / 700.
SRX would establish many firsts for Yamaha. For starters the clay modeling and wire frame work was performed in the USA to reduce some cost and speed up development. I was asked to travel down to the GKDI offices in Torrance CA where we worked closely with the designers on the shape and dynamics of the new machines. Prototypes were built based on the SX chassis and targets were established using the SX 600 plus ZRT in the 600 category and SX 700 plus Mach 1 in the 700 niche. We decided to build a modified version of the lower 8-inch SX chassis to house the new power-plants, because the sled was intended to handle better than any lake racer before it. Initial testing results were quite promising.
The SRX would be our final two-stroke snowmobile development project and it seems quite fitting it would crown 30 years of Yamaha in the sno-mo biz and mark the one millionth sled to run off our lines japan-media-remaster.pdf … more to follow.