Corbin Mills
Newbie
- Joined
- May 22, 2019
- Messages
- 1
- Age
- 28
- Location
- Wyoming
- Country
- USA
- Snowmobile
- 2015 SR Viper MTX 174" MCX 270
Having some trouble with my 2015 MTX. It has the MCX 270 turbo kit and a 174 track. I've only owned it for a few months and have ridden it 4 times. Bear in mind that this is my first 4 stroke. I'm coming from a 99 mm700.
First ride: running 91 octane, topped out just over 90mph. It was a blast.
Second ride: running 100LL, topped out just over 120mph after I fixed the footwell which was rubbing on the secondary clutch.
Third ride: suddenly couldn't get the sled over 55 or so mph. It still has plenty of low end grunt, but falls on it's face around 50. Found a broken primary clutch spring after the ride and replaced it. Clutching appears to be stock with a blue/white/blue Yamaha spring, but I'm not 100% sure.
Fourth ride: took it out last weekend with the new spring and still can't get it over 55 save for one short burst where it came to life, and I hit 70 before running out of room.
I do not believe this is a turbo issue. My boost gauge is a little messed up (sits at 10 inches of vacuum at idle), but it gets up over 10 PSI and holds it there at 50mph. Can hear the blowoff valve when I let off after making 50mph. It also tops out at around 8300rpm instead of the 9000+ it would spin prior.
I'm kinda at a loss as to what to look at next. I don't understand what could've changed between rides 2 and 3 to see such a drastic loss in performance. Any advice would be appreciated. We got 2 feet of snow on the mountain today, and I'd like to get another ride in this weekend.
Pictured are the broken spring and the sled itself. Can get more pictures if it would be helpful.
First ride: running 91 octane, topped out just over 90mph. It was a blast.
Second ride: running 100LL, topped out just over 120mph after I fixed the footwell which was rubbing on the secondary clutch.
Third ride: suddenly couldn't get the sled over 55 or so mph. It still has plenty of low end grunt, but falls on it's face around 50. Found a broken primary clutch spring after the ride and replaced it. Clutching appears to be stock with a blue/white/blue Yamaha spring, but I'm not 100% sure.
Fourth ride: took it out last weekend with the new spring and still can't get it over 55 save for one short burst where it came to life, and I hit 70 before running out of room.
I do not believe this is a turbo issue. My boost gauge is a little messed up (sits at 10 inches of vacuum at idle), but it gets up over 10 PSI and holds it there at 50mph. Can hear the blowoff valve when I let off after making 50mph. It also tops out at around 8300rpm instead of the 9000+ it would spin prior.
I'm kinda at a loss as to what to look at next. I don't understand what could've changed between rides 2 and 3 to see such a drastic loss in performance. Any advice would be appreciated. We got 2 feet of snow on the mountain today, and I'd like to get another ride in this weekend.
Pictured are the broken spring and the sled itself. Can get more pictures if it would be helpful.
