Confused on clutching ?

w8tn4snow

w8tn4snow

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Joined
Oct 20, 2006
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156
Age
50
Location
upstate ny
Ok I just spoke with the folks at Bender and they said i would have to add weight to my clutch arms not take weight off . They said by adding pipes I add HP and that causes the clutch to engage faster and hence to overrev . I have their trail setup on now with 8EK clutch arms with their 6.1 gram rivets in them . They said to go up to about 7 grams in the tip . . I know noone sells a rivet this size so they said just to put bolts in there with alot of loctite . Does this sound doable ? Im confused because i was told before that I would need to take some weight off .
 

No, bender is correct. You will need to add weight. With more hp you do need to add weight to keep it from over-reving. More weight will also give you more belt clamp. The belt will not slip as much now, so less heat is generated, so the belt should end up lasting longer. Bolts will work as long as they weigh the correct amount that you need.
 
theres some more information that comes into play also, it all depends upon the springs rate in the primary as to what your rpm will be because the springs rate will dictate along with gearing the amount of weight the engine can pull. your arms are 39 grams each with (2) 6.1 rivets in them your at 51.2 grams each. Do you know the springs rates in the primary? is it other then stock? stock was a yellow/white/yellow. Your topend rpm also will be dictated by the helix your running in the secondary clutch a steeper helix finish angle will lower your rpm's, because your loading the engine via the secondary as well.
 
Stock Viper make peak HP @ 8500
Bender piped Vipers peak HP @ 8700

So you need a little higher RPM anyway. I'd personally try what you have first and tune from there.
 
I do have the stock 8EK weights with only one 6.1 gram rivet in the tip of each one wieghing a total of 45.1 grams . I have benders Yell/Orange primary spring they use in their trail kit . along with their helix and BLK/Silv in the secondary . The way i understood I was gonna need to pick up 200 RPM in the clutching after I installed the pipes . Nowtheyre telling me the pipes will cause the clutch to overrev at about 9000 RPM and ineed to lower the rpm by adding weight . I guess im either confused or getting 2 theories .
 
You're thinking too hard. The motor with the pipes makes more power, thus it will pull the same weight at a higher rpm. If your pre-pipe set-up runs 8500rpm in theory with the pipes (if you don't change your clutching) you'll pull 9000+. That is why you'll need to add weight to bring the rpm's back down to the 8700 rpm sweet spot that they recommend for the pipes. Obviously there is much more to consider like spring rates, helix, gearing, etc.. but I think it covers your question.
 
well i just put hauck triples on my red head today, brought the revs down to 8000 from the 8500 i was running last year. my view on this is the added hp swings the weights out with more force thus compressing ithe spring faster witch brings the rpms down so i have to take rivets out or go to a stiffer spring to bring the revs up. nowhere near being a clutch expert but this is what im gonna be working with . dont know if this helps you ? everyone pitch in here.

Pat
 
Thanks , now Im really confused . i guess im just gonna have to wait and see what its running at when it gets back together . My head has been out to Bender for 3 weeks now , they said a 3 day turn around , boy were they way off !
 
Bender told me 2 to 4 weeks turn time to get the head done. I got really leery with sending my head to bender so I bought a peak head instead. I also have the Bender clutch kit. But I didn't get the spacer for the primary spring that was supposed to come with it. So I bought a set of heel clickers instead.

I have searched for the helix angle on the Bender VIP helix and I never did come up with it. I also read that it was supposed to be installed at a 30 wrap? http://snowmobile.off-road.com/snowmobile/article/articleDetail.jsp?id=195525 I put mine at 60 as that was where my stock one was. I also used the stock helix spring.

I set the heel clickers to their recommended setup. Now after reading some of Dons posts on clutching I forsee changing that. Right now I have the grey spring in it and will be swapping that for the red spring. I just want to ride it first and get my jetting right. I also swapped my primary spring without removing the clutch. Never doing that again...

http://www.totallyamaha.net/forums/showthread.php?t=32944&highlight=clutch
http://www.totallyamaha.net/forums/showthread.php?t=31863&highlight=clutch
 
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