kart74
New member
I have it on the way. Still run the red at 80 or stay with green? Thank you for all the help everyone
kart74
New member
Did a compression test and is low. I ordered new rings, and will open it up. Hopefully that is all it will need. I did have the DCS light flash a few times the other night when riding. Seemed to be in the mid range at 3/4 throttle. Prob needles, but it was also 0 out.
Vincent
New member
Mite want to double check your compression numbers with another gauge. Mine recently started giving 15 to 20 psi lower numbers then another known good one. Compression gauges are great but can also be misleading. That's why I often use my leak down tester instead.
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kart74
New member
yea this is a brand new one because my old one was leaking. I got 100-110-110 for readings.
the pto wll be a tad lower if you haven't touched the heads. yamaha staggered compression on the vipers instead of staggering the jetting
kart74
New member
Right. I knew that was the case but shouldnt it be more.like 120-135-135?
mod-it
Member
It all comes down to the gauge. I know that pipes make a big difference on a Viper, but if you're waxing other Vipers I wouldn't personally be too worried about those compression numbers.
I can't give you a comparison of what weight my sled is pulling compared to yours as I have a 144" track and 40-21 gearing. But I honestly don't think those numbers are too terrible.
Maybe someone else running HC's and similar clutch setup can share what total weight their pulling at what peak rpm to give you an idea of how strong your motor is?
At the very least, with sledding time per year being so short, I'd probably run it this year and then do a top end during the off season.
I can't give you a comparison of what weight my sled is pulling compared to yours as I have a 144" track and 40-21 gearing. But I honestly don't think those numbers are too terrible.
Maybe someone else running HC's and similar clutch setup can share what total weight their pulling at what peak rpm to give you an idea of how strong your motor is?
At the very least, with sledding time per year being so short, I'd probably run it this year and then do a top end during the off season.
compression tester all read different due to hose length, adaptor volume, etc. I wouldn't worry about the number as much as the same number on the center and mag, pto will be less due to larger volume chamber on the head. I don't think compression is the problem.
I also wouldn't start just throwing different radical difference helix at it and hoping to hit a bullseye, as your going to have to keep changing out the center weight to adjust for rpm. You tune the front clutch for rpm, not the rear clutch! the helix merely tailors the shift. Nothing wrong at all with the 51/37 if you know for a fact its a 51/37. Where most guys get into trouble is they buy" coded helix" from bender,hauck, maxx all used codes so the average person couldn't just go and copy a clutch kit easily. Guys think that's the angles because someone posted a list. I can tell you the list I have seen posted has a lot of wrong information on it! also one brand helix will shift different from another brand due to the radius cut on the ramp. For example if you had a known 50/40 from hauck and a 50/40 adavntedge, youll see 100's of rpm difference in them and a way different shift curve!
I also wouldn't start just throwing different radical difference helix at it and hoping to hit a bullseye, as your going to have to keep changing out the center weight to adjust for rpm. You tune the front clutch for rpm, not the rear clutch! the helix merely tailors the shift. Nothing wrong at all with the 51/37 if you know for a fact its a 51/37. Where most guys get into trouble is they buy" coded helix" from bender,hauck, maxx all used codes so the average person couldn't just go and copy a clutch kit easily. Guys think that's the angles because someone posted a list. I can tell you the list I have seen posted has a lot of wrong information on it! also one brand helix will shift different from another brand due to the radius cut on the ramp. For example if you had a known 50/40 from hauck and a 50/40 adavntedge, youll see 100's of rpm difference in them and a way different shift curve!
kart74
New member
Yes great info. The Bender helix i have has 51/37 engraved in it. The 46-34 i just got is from Maxximum performace as they are clearing out their stuff. I will stay with what i have for now since the season is short. Maybe next year i will try the other. As for the compression... I dont have a opticool gasket in it right now, so i ordered one of those. Figured it is good insurance if anything. When i did the test, i thought maybe to just do rings. If i am opening it up for the head gasket, it would be just a bit more to do rings. Wouldnt hurt right? Then i know what i am working with. Thanks again for all the help. Nice to have a place to go bounce ideas off others.
Do you have a link to the clearance sale?
kart74
New member
It was on a facebook group. Yamaha 2 stroke triples. You can message her. Paige polyak is the one posting it all.
that sucks, couldnt give me the stuff to use facebook. Thanks anyway.
kart74
New member
I was able to get some more time in before the snow melted. Ran the red spring in the secondary at 80. It ran really good, but maybe dropped a bit of RPM. It was 8900-9000 which i am still good with. Since the snow is gone i am going to throw rings and the opticool in it. Hopefully the pistons are in good shape so i can just reuse. If it does need pistons are the SPI moly coated ones ok? They are much cheaper that OEM.
The OEM vs aftermarket pistons has been debated countless times, OEM for the average guy seems to be the choice, with the aftermarket ones being lighter and forged not cast they heat up quicker, if you are a mindful individual and can bring the entire motor up to temp, maybe the aftermarket piston would be fine. I prefer not worrying about a cold seize, especially when most of my riding buddies pin it within minutes of firing them up.