8DN20 vs 8EK weights

kinger

kinger

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Clear Lake, IA
What is the advantage of running 8DN20 weights with 15.6mm rollers vs the stock 8EK viper weights with the 14.5mm rollers? I'm trying to finalyze my clutch set up and can't decide if I shoudl switch weights or just add 2 grams to my current set up to get the revs down to where I want?

What is everyone reccomendation on a primary spring for a stock viper? There is a blue in there now. I have a Y-W-Y would there be a benefit to running that? Thanks!
 

The 8eks Have A Nice Up Shift Than Fall On There Face.
The 8dn-20s Are More Linnar And Have A Much Better Topend.
Go With The 8dn-20s
 
Magic pretty much said it all ;)! The 8DN-20's are yamaha's "polaris profile" weights, they have a lot of meat all the way through with a very linear yet quick upshift.
 
Sounds good, I'll install them with the current rivets and see how she runs out.

What primary spring is reccomended I have a blue one in there now and I don't think that is stock, probably from the fix clutch kit. Is that a dalton spring maybe? Should I leave it or swap for a Y-W-Y?
 
King, if you do not know what blue spring [rate] it is. stick withe the Yamaha y-w-y
45kg preload 128kg total force at 33mm.
And if want to try a different setup for you viper p.m. me
 
the DN-00's have A LOT of tip weight, going to need a lot of primary spring preload or a shallow finish angle to pull the tips on those babies....or triple pipes ;)!
 
8dn-00,s have a very shallow shift curve so even tho they are heavier they are not as aggressive. Any weight with this profile has a lot of tip weight. You need to run a lot of mass in these weights to make em pull proper rpm,s.
 
Turk, what rivets would you recommend? They looked to be already loaded and I was thinking of running a 47/41 Dalton helix. I have heel clicker springs and a Bender Primary to try also. Would gearing down a tooth help them out?
 
yamaholic22 said:
Magic pretty much said it all ;)! The 8DN-20's are yamaha's "polaris profile" weights, they have a lot of meat all the way through with a very linear yet quick upshift.
Click to expand...

Will this setup work better in my 02 Viper than the stock weights? I do have the 53/43 helix with the green spring in the secondary. Had good results with that setup. What will the difference be? Just looking for something more. Would like the engagement rpm to be higher. Would these say" be a bolt in and go setup". Or will they have to be tuned? Thanks for input. Would rather play with this than buy a aftermarket kit. ;)!
 
You will likely need to tune some. I have the 8DN20's in mine, a set up reccomended from this site. But I think I ended up with 4.5 grams in both holes, the 53/43 and green spring in the secondary and a funky spring in the primary to get it where I like it. I'll have to check on that one and let you know. But to anwser your question, I think every sled is a little different and the set up's are a starting point. So you may need to tinker with it some. But that's half the fun!
 
you probably dont NEED to but you will have to run a spring with a lot of preload to get the engagement up to where it should be
 
One thing you guys must remember when clutch tuning. Don't go right from your garage/shop and do a 1000 foot blast and then come back and change something because it ran 8800 rpm if you're going to mainly trail ride this setup. Get the engine up to normal operating temps and most importantly get the belt up to normal operating temps. A cold belt will produce more rpm because it acts like a harder compound, but when it gets warm it acts softer and pulls the rpm down.
 
Good info allen, I read a article somwhere about the belt temp and effects of cold vs hot...I'll try to find it again. It was interesting.
 
also remember that the more efficient your setup is, the cooler your belt and sheave temps will be
 
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