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Mountain viper?


I can't thank drew enough for putting in the hours to get the ball rolling on this build and getting me hooked on boost! There will be more pics to come :sled1: :sled1: :sled1:
 
According to this YouTube video, the AC M800 154" weighs 564 lbs with a full tank. How does that compare to your 163" Viper with a gallon of fuels?

If my calculations (guesstimates) are right, the Viper is 30-40 lbs heavier than the M800, which isn't bad! And if that is true, why is the Nytro chassis so heavy??
 
Got the viper out today. This thing is impressive to say the least. This motor/chassis setup is awesome and I wish yamaha would have done it from the factory. Super light on the skis, very nimble, quick to react and awesome trail manners. All of which the nytro never was.

One major complaint I have though is the oil pump loses it's prime if and when it rolls over. Not a good feeling or situation for most, luckily I got it running but for the average joe I feel they would have been stranded. I think yamaha needs to come up with a fix for this ASAP! I have never had a apex or nytro lose it's oil pump prime during the ride, and I've rolled my sleds hundreds of times without issue.

Anyway, here's a pic of our first ride out. Wasn't great conditions but the sled handled great and makes good power. Now it's time to add more!
 
Interesting...

Is this issue something that can be fixed? Does the pump need a better flooded suction? Air relief?

Does this sled need a roll over valve like the nytro does so you don't lose your oil into the air box on a roll over?

Just concerned cause I am building one of these with a mcx 190.
 
No video, sorry. The go pro we had ended up having crap footage that's not even worth watching, had snow all over the lense.

The roll over thing I will be looking into. A tether will help but I would still love to hear what yamaha says. The oil didn't go into the air box though, it just filled the tank and sat there making bubbles. We were able to choke the breather to the air box off and it primed itself back up. Not a easy task though in the field.
 
That's unfortunate, I never had that issue with either my Vector or Nytro either but I didn't roll them too many times. How did you know it lost prime? Did the oil light not shut off and you had an assumption? How would a guy know?
 
When they lose their prime the cam chain tensioner becomes very loud and noticeable. A lot of valve train noise makes is very obvious. When you build these motors they can be hard to prime as well and the same noise is heard upon first startup or until primed. Not a huge issue once a tether gets on here but I'm still curious as to why. I've seen many nytros run upside down and not lose their prime completely. Hopefully have a answer soon, I know the solution I just want a answer.
 
birkebeiner said:
According to this YouTube video, the AC M800 154" weighs 564 lbs with a full tank. How does that compare to your 163" Viper with a gallon of fuels?

If my calculations (guesstimates) are right, the Viper is 30-40 lbs heavier than the M800, which isn't bad! And if that is true, why is the Nytro chassis so heavy??[/quote]


Nytro skid is 35 pounds heavier than Timbersled skid just in that one area, let alone other areas. I cut a Nytro down to 541 wet and it still handled bad due to being top heavy. It appears Cat has resolved most of the top heavy issues though (gas tank under seat, ETC). Too bad the Colorado dealer I use has said they are not getting any Vipers I would sure like to ride one....I would probably buy one if it rides ANYTHING like my 2014 M8.
 
They can range anywhere from 14k -18k depending on setup and what all we do.
Really hoping yamaha comes out with this sled next year. It's in every way better than a nytro, can't wait to get it in the trees and see how it does but I have a feeling it's gonna be awesome.
 


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