8EK vs. 8DN-20 on stock Viper

Thumper1

Thumper1

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Aug 22, 2006
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Location
Western Illinois
how do these two weights compare? are the 8dn-20s a better weight to use than the 8EK? just don't want to leave anything on the table and if it would be worth it to put some 8dns in instead of the 8ek. have the 54/44 helix, green secondary and orange MaxxPerf primary spring in there already with 4.5gs in each hole.
 

8dn-20 is 42.09 grams and heavier then a 8ek which is 39 grams, and having the 2 weights side by side the 8dn-20 is heavier thru the beginning of the weight(holeshot area)but according to the yamaha clutching chart the 8dn-20 holds a flatter shift curve then the 8ek does, the viper weight significantly drops off after mid range so I would guess with a little bit of tuning you could get better accelaration and better top speed from the 8dn-20 then the stock viper weight. You might try and match overall weight with yours and the rivets and make the 8dn-20 weigh close to the same and try em, ya never know till ya do some testing!!!!
 
thanks, that is what i was wondering since i didn't have an 8dn-20 to compare with. when it comes to yamaha clutching, it seems there is always room for improvment.
 
I Know I'm Jumping in here but I had a same question. Do you know that the Vipers did not originally come with the 15.6mm rollers or is that just something to check? I have a low miles 2003 viper that was just purchased this summer and I know the clutches had not been touched. I have not pulled a roller out to check but it seemed about 15.6mm at least as close as I could get with my ruler. I am not near my sled now so I can't check but I already have the 8DN20s to try. That is if I ever get near snow.
 
vipers come stock with 14.5 rollers, the 15.6 is stock from a srx, either one can be made to work depending upon rest of clutch recipe used.
 
I ended up here two years ago and love this setup. This was after a ton of trial and error with the 8EK's and could never keep it from over reving. 8dn20 weights with 4.5 in both. Yamaha Y-W-Y spring. A 51-43 dalton helix with green yamaha secondary spring set at 60. It pulls steady all the way at 8500-8700. Stock rollers and geared down one tooth on top.
 
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