sledneckdon
New member
I am looking to gain back some top end on my 2004 single pipe Viper. My dealer installed a Green secondary spring, 8DN-17605-20 weights with 90261-06033 (4.5 Gram) rivets 2 in each. The only other mods are engine torque limiter and idler wheel spacers for better Hyfax wear. the sled pulls great in midrange topping out at 8500-8600 RPMS WOT but I lost 8 to 10 MPH top end. Should I try putting the stock secondary spring back in??, install a multi angle Helix (if so what angles)??, or go up one tooth on the top gear???? I am looking for what will work best with the set up I have now without having to buy all new parts or go back to stock. I am test running the sled in the same conditions and location each time. I'm running on extreamly hard packed snow on top of perfictally flat ice. I have no studs but have enough hard pack snow to hook up nicely with the ripsaw track. It is approximatly a 1/2 mile run.
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what degree twist on secondery are you running? strange if the green spring make you loose top end if its not way to tight? try 60 or 70 degrees..?
sledneckdon
New member
I believe it is set on 60 or whatever it was set at from the factory the dealer changed the spring but left the spring twist setting stock.
if all you changed was the weights why did you need to change the sec spring? the stock 47 helix doesnt need a green spring, the red stock spring would be fine in there, the red spring is softer and you will get more topend mph from it.
So you have stock y/w/y primary spring, 8dn-20 weights with 4.5 in each hole and a green sec. spring with a 47 helix??
stock 8ek weights would be 47.10grams with rivets that came from yamaha, the 8dn-20 weights are 51.09, so you have added 3.99 grams or 4 grams to the clutch, if your still running at 8500-8600rpm with the red spring there would be no need to change to the green unless you were using a larger then stock helix. The 8dn20 weight isnt really more aggressive then the 8ek, but it has a steady shift curve where the 8ek weight falls off, I cant think of any reasoning for a green spring in there????
So you have stock y/w/y primary spring, 8dn-20 weights with 4.5 in each hole and a green sec. spring with a 47 helix??
stock 8ek weights would be 47.10grams with rivets that came from yamaha, the 8dn-20 weights are 51.09, so you have added 3.99 grams or 4 grams to the clutch, if your still running at 8500-8600rpm with the red spring there would be no need to change to the green unless you were using a larger then stock helix. The 8dn20 weight isnt really more aggressive then the 8ek, but it has a steady shift curve where the 8ek weight falls off, I cant think of any reasoning for a green spring in there????
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EricMichael
New member
what size is your ripsaw?did you change the track recently?mess with suspension?get a 51/43 helix, thats a shallower finish angle, it should help your top end and improve your acceleration.Make sure your exhaust valves are clean, and adjusted right, that greatly effects top end also.
sledneckdon
New member
Yes Sir, I see your point. However, when we added the 8DN-20 weights he also added the Green spring so I am not sure what it will run if we put the Red Stock spring back in with the added weight. Do you suggest putting the Red Stock Secondary spring back in and try it??? The thing pulls like a freight train in midrange now but the least bit of resistence on top end and she slows right down to nothin. The TECH page is showing the 8EK-00 weight as 39.0 grams without rivits. Did they come from Yamaha with 8.1 Grams worth of rivits in them????mrviper700 said:
vipers came with a 4.5gr rivet inside hole and a 3.6gr rivet outside hole,=8.1 grams added to the 39.0 base weight 8ek ramp.
I would try the red sec. spring first, play with the amount of tension till it backshifts and runs on topend where you want it.
explain to me what the sled does on topend with slight bit of resistance.
I would try the red sec. spring first, play with the amount of tension till it backshifts and runs on topend where you want it.
explain to me what the sled does on topend with slight bit of resistance.
sledneckdon
New member
Stock Rip Saw 1.25 Lug track, Only suspention work was custom valved KYB shocks from Pioneer. I was told that the stock Helix from an RX-1 is a 51/43. I am running the stock 47 now. Considering trying the 51/43 but awaiting Mr. Vipers reply. You guys are the true experts I am new to this but have worked on Military aircraft for the last 22 years so I can appreciate good sound advice from people who have a better working knowledge than I.EricMichael said:
sledneckdon
New member
I plan on making the adjustments you suggest and then try it again this weekend. The only way I can explain the Top End resistence is the sled slows down drastically even when just hitting a small patch of light fluffy snow it goes from 108MPH down to 98MPH quick.mrviper700 said:
sledneckdon
New member
bump up
When you hit fluffy snow coming off of a different surface such as ice or hard packed the sled is really going to slow down that's normal.