Posted by Chris on August 13, 2009 under 2-stroke, Cat, Product Planning, SRX, Skidoo, Yamaha, Yamaha Insights, snowmobile, supertrax, suspension, testing | 
Thinking it might be time to wrap the ‘Snake Eyes’ saga. I jumped in my tin-boat after our regular Sunday rainstorm to bail it out . Third scoop of the bucket and a young water snake slithered out from under the fuel tank platform aggressively swimming directly at my writing hand, had to use a paddle to evict her… perhaps she was delivering a message .
And so it was, the SX Viper became a highly refined variation of the SXr. The new engine proved to be
extremely efficient and bullet proof. I’m not so sure the FAI (ram-air) feature was near the benefit we had hoped, although Saito still swears it makes a difference of three to four horsepower at top speed. I remember how much attention was spent on the air management and layout, one example of the level of detail that goes into a Yamaha can be seen in this sound hologram analysis: 0MC0717.
The engine was sneaky fast, not as hard hitting as the big twin 800’s but far smoother and more linear in it’s delivery. Although the horsepower numbers didn’t peak that high on the dyno, the torque was very ‘usable’ and ‘tractable’, it ‘got ‘er done.’ More importanly (at least to Yamaha), very few ever ended up on the wrong end of the tow rope and we also set the bar for low fuel and oil consumption. I found this report on the competition which I wrote after ridng all the new stuff at the Snowshoot in Yellowstone, I think it was: Snow Shoot 02
The Viper’s marketing had to be tweaked somewhat due to all the changes in the original plan. Several ‘creative briefs’ occurred. I found this marketing strategy document from the ad agency working on the Viper account. It is based on their market understanding after meeting and discussing with our people. Note the names have been changed to protect the innocent 
: 2002SXViperBlueStrategy . I can’t duck the bullet when it comes to marketing hype, I also found this letter I wrote, which was part of a direct mail campaign to Canadian owners of SXr’s and SRX following the release of the new Viper. Hey I only had to swallow hard once! Snake Bit
The first season we had a lot of feedback regarding the ride comfort of the SX Viper. Most were pointed at the shocks and skid frame set-up while some questioned the seat firmness. This eventually led to some countermeasure specs and I remember taking off for a few days with my riding partner Mike Collins and Steve Brand from TekRiderto do some real world testing and evaluations. Steve volunteered to do the trucking and we headed north after picking up the Supertrax Viper press sled which Mark and Kent had been struggling to dial in. I still remember the Supertrax article recommending everyone remove all pre-load from all four shocks as the ‘hot set-up’ for trail riding, it was that sled I wanted to try. We also had a base line stocker and one with the latest countermeasure spec from factory. Steve wanted to have us test some of his latest TekVest products and he had acquired a set of the then ‘new’ Precision skis from Skidoo. Here’s my report from the archives. It dosen’t include the part where after breaking trail for many miles we all ran out of fuel. If it had not been for an abandoned Cat with a very tight engine and full tank of gas we’d of been in some serious doo-doo. Steve did the honors of sucking on the siphon hose and remarked how much better the premium fuel in the kitty tasted compared to the regular gype he had just sucked from Mikes sled to stay in the game. The way I saw it is; we made the Cat much lighter for the tow out, no worries, you are welcome…
Made me smile to review after this many years. I’ll let you read between the lines. After the report was written several of the items I referred to were addressed in different ways, including at least one lawsuit for Skidoo (we have been and still are, struggling to find a good ski / skag design that is not patent protected): reportSXV02
The second year Viper’s had most of the wrinkles removed with improved suspension settings. We also came up with a controversial shock update kit for owners who found their 02’s too stiff. The rear heat exchanger was also addressed (originally left off to save weight and cost based on testing that indicated we could live without one). And then there was the ViperS complete with adjustable Ohlins front shocks and the Ripsaw track / deep keel ski cloned from the RX-1… what a difference, what a great sled! (not unlike the Exciter SX scenario), get it right and discontinue… d’oh!
So there you have it. What started out as a clean sheet of paper became a nicely evolved snowmobile based on many existing parts and refinements. It is my perception of this which led to my post entitled: ‘The Last 2-Smoke’ which talked about the SRX being the final new 2-stroke developed by Yamaha before going full-on 4-stroke. It’s debatable whether the Viper is truly the last 2-stroke that Yamaha developed, just depends how you look at it. Matter of fact I understand that the Bravo is getting a clutch update next year, maybe that should qualify
I ho
pe you enjoyed this little series. If Saito comes up with any more de
tails or images I’ll do an update down the road. Until then I must get back to finishing up my cottage and fending off snakes.
cheers cr
Posted by Chris on August 5, 2009 under Apex, Product Planning, SRX, Skidoo, Yamaha Insights, bump sled, engineer, marketing, pre-production, snow, snowmobile, suspension |
Before I jump into the next part of the Viper story, there are a couple of news bits I’d like to share with you. First our very own Randy Swenson has been recognized as mountain rider of the year for his performance in Thunderstruck 7, (link to see the new trailer for TS8), which also received the Oscar for extreme snowmobile film of the year. Congrats guys!
And for the go fast crew, it is official, Gilles Gagne and his G-Force / Lamtrac team have been officilally accepted by the Bonneville promoters and world sanctioning body, the FIM to challenge the world speed record with their blown Apex streamliner during speed week on the salt, September 20-26, Wendover Utah. He is silently hoping to break the motorcyle record of over 300 mph!
… The monoshock performance became the main focus for the ‘what’s next’ debate. Engineering finally concluded that the ill fated ‘boinger’ could not be massaged into an acceptable component leaving us with only one option, use the Pro-Action plus system. The domino’s started to fall in sequence. Without the long travel mono-shock the unequal length, rack-steer, front end plans died on the vine and next thing we knew our baby had morphed into an SXr chassis / suspension with a lightened up SRX motor. A long way from the original ‘all-new’ concept.
None of this helped to hit our weight targets which would have seen the Viper coming in significantly less than the SXr700 but how could it when it used the same chassis and suspension? The suspension eyeball was still aimed at a big bump / ditch banger target. The original testing criteria for the monoshock system was set to run a section of 3-3.5 foot bumps spaced at 20 to 40 inch intervals running a steady 35 to 45 mph…sitting down! The gentleman from sales who was adamant about this is no longer employed by Yamaha so I can say this… buddy you were outa your gourd!
I have learned when speaking with many sledders, the moguls they describe are often scaled similar to their manhood, where the three foot bumps they’ve been riding all day are really a foot and a half at best. Regardless, once a target has been established we don’t mess with it and when the monshock went away the ProAction really had its work cut out for it.
We had several years of tweaking the Pro Action system and as we all know, there is no magic setting to offer a plush ride and still resist serious hits. It was explained to me once that the first 8 inches of suspension stroke was fairly progressive but became linear towards the latter part of the travel then digressive as it fell through itself at the end. Think of it this way, riding through a series of 1-2 foot stutter bumps with the suspension stroking under ten inches, life is pretty good, staying flat and plush, that’s progressive. Now bomb down a smooth hill with a g-out at the base pushing the skid deep into the stroke and hit a small frozen pine cone, suddenly it bottoms hard and unexpectedly, loosening up your back fillings and sending that unmistakable tingle up your spine (that’s the digressive part.) ouch!
It was this severe bottoming that could break stuff and in the case of a bump sled, needed to be addressed.
Whenever the spring rate was stiff enough to limit the bottom out, ride comfort suffered. Engineering was reluctant to use multi-rate springs and position compensating valving and Kayaba had certain limitations to settings if there was a chance of bending the damper rods. In the end the short center shock received some very stiff compression damping and the stiffest spring we had. The ride wasn’t plush but it could take a pretty good hit. But, as fate would have it, someone made a change to the front shock spec after final testing / pre-production sign-off and before production. I have not been able to find out exactly who or why but the first production units started showing cracks in the hoods, which after investigation, was credited to over damped front shocks. Instead of the small bump energy being absorbed, the shock remained rigid and all the rattling went into the chassis. At the same time the stiff front end was being kicked up by the bumps which were now coming into the center shock farther back and effecting the coupling point making the already stiff rear end even less compliant…
In the next segment I’ll focus not so much on what we had intended to build but what we brought to market and how we positioned it. I spoke to Masa Saito (seen in this Alaskan fishing trip photo) earlier this week and he promised to dig up some development stuff when he is at factory later this month. I have some interesting documents from the research and marketing side to sprinkle in. cheers cr
Posted by Chris on July 21, 2009 under 2-stroke, 4-stroke, SRX, Skidoo, Yamaha, Yamaha Insights, bump sled, groomed trail, polaris, prototype, race team, snowcross |
Part 1
This multi-part post is dedicated to Yammerhead, who first called BS on my SRX story titled the “Last Two Smoke’…
The SX Viper, code named OMC started it’s development in 1999 with a target launch for model year 2001. We were 
looking to fill the void between the SXr and SRX with a highly capable ‘bump-sled’ for the American market which would also offer great agility and handling on our groomed trails.
The SRX had hit us a home run in the top performance field taking on all comers including the T-Cats and emerging big 
twin 800’s from Skidoo and Polaris. What we needed to do was update the aging SXr with some fresh styling, new suspension and more power with emphasis on the suspension. YMUS research led planning to chase the holy grail of mid-west snowmobiles: the ultimate big bump sled, (something that we always struggle with here in Canada, but more on that later). We proposed the idea of an 800 twin but engineering convinced us a hi-tech triple would yield equal or better power with greater reliability and efficiency. It was around this time that the advanced group was investigating the potential of 4-stroke power and so it was decided to evolve our SRX engine base into a lightweight, single pipe trail burner.
My old pal Masa Saitou was appointed ‘project leader’ for OMC based on the success of his most recent sled, the SRX. Aggressive targets were set for both engine and chassis as engineering began the minus prototype development. Meanwhile the design team at GKDI in California were fast tracking the body and styling. One of the most exciting developments came in the form of an all new rear skid frame that had a large single gas-shock with a floating coupling-point between the two arms. The ‘mono shock’ made its debut on the prototype Viper but would never make it to production on a 2-stroke sled…
Yamaha USA had reentered the snowcross game racing modified SXr’s in the pro open class under the guise of product development (sound familiar?). Gordy Muetz took on the challenge of building and managing the team which was run out of our short lived Minneapolis based snowmobile headquarters with support from Minocqua and factory. Ron Ruzewski (click on ‘Race Team’) was the engineer who designed the new front suspension and chassis working closely with YMC engineers. By the time things were race ready, Ron had come up with a ‘race kit’ which was adaptable to the SXr and pointed squarely at the new SXViper. A small number of these kits were made available to supported race teams. 0u58a suspension
I could not resist the temptation to build my own project sled in 2000 with Ron’s help, based on the SXr with triple ‘Power Inc’ pipes to make the equivalent hp target of the Viper. It incorporated the early mono shock and long travel front end with rack steering and a smattering of other goodies, (roller secondary, tunnel reinforcements and special one-off, Yokohama track to name a few).
It’s important to add this to the story because it has a lot of bearing on what was to come for the Viper. There was a lot to like about my mod sled but one characteristic emerged rapidly in the form of weight transfer (or lack there-of). Chris Vincent was racing a very similar sled in the pro ranks and the shock package we had was about as plush as a fire hydrant. The sled would only work well when held WFO. There was no timing the bumps and blipping the throttle for lift. It was a ‘mash fest’ only- if you lifted at speed you’d auger in- and if you ever watched Vincent muscle his way around a snowcross course you know what I mean. We finally had a true big-bump sled, the question was who the heck would want to ride it like that in the real world.
…to be continued
And so it was, the SX Viper became a highly refined variation of the SXr. The new engine proved to be
extremely efficient and bullet proof. I’m not so sure the FAI (ram-air) feature was near the benefit we had hoped, although Saito still swears it makes a difference of three to four horsepower at top speed. I remember how much attention was spent on the air management and layout, one example of the level of detail that goes into a Yamaha can be seen in this sound hologram analysis: 0MC0717.
The engine was sneaky fast, not as hard hitting as the big twin 800’s but far smoother and more linear in it’s delivery. Although the horsepower numbers didn’t peak that high on the dyno, the torque was very ‘usable’ and ‘tractable’, it ‘got ‘er done.’ More importanly (at least to Yamaha), very few ever ended up on the wrong end of the tow rope and we also set the bar for low fuel and oil consumption. I found this report on the competition which I wrote after ridng all the new stuff at the Snowshoot in Yellowstone, I think it was: Snow Shoot 02
pe you enjoyed this little series. If Saito comes up with any more de
tails or images I’ll do an update down the road. Until then I must get back to finishing up my cottage and fending off snakes.
