Ideal Clutching

OldIron

OldIron

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Joined
Nov 13, 2010
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Ok clutching is new to me but I need to get smart on it. I've read a lot of posts and I've been through the tech section. My first question is "in the perfect world" should a clutch allow the engine to go to it's best torque rpm and then stay there throughout the pull up to max speed? I'm just trying to view the desired outcome.

I have a viper that was over-revving up to 9100 to 9200 rpm (all stock except can). So I decided to throw my other vipers clutch on which was a non-electric start clutch unlike the first. With the second clutch the initial off the line was about 8600 to 8700 rpm then it crept up to 8900 rpm in the middle but slowly came down to 8600 rpm toward the end of the pull. Is this clutch acting correctly or does it need some tuning also?

Both these sleds are mtn vipers with stock mtn setup (except can).

Weights 8DN 10
Rivets over-revving clutch (inner-there's a rivet, tip nothing)
Rivets in better clutch (inner-a rivet, outer-a rivet)
rollers 15.6mm
Primary spring GWG


The averaged weight of over-revving clutch weights (with rivets)= 46.683 g
The averaged weight of better clutch weights (with rivets) = 43.926 g

Over-revving clutch spring is 91.06 mm length
Better clutch spring length is 89.3 mm length
The book says it should be 89.8 mm


Not really paying any attention to the secondary I was thinking about doing the following:

Add either 2.7 g rivet or 3.1 g rivet to the tip of the bad clutch weight. That would get the overall average weight to the same as the better clutch. However, I'm thinking that without knowing which rivet weights are in the inside and tip, my logic may be faulty. However, I think it should get me close. Is this reasonable?

Also I was thinking that the spring on the over-revving clutch needs to be replaced since it is longer then what it's suppose to be. Is replacing it logical or is it close enough?

I'd appreciate any insight.
 
I believe you want the clutches to allow the engine to immediately go to the rpm where it makes the most torque and then climb to the shift rpm where it makes the most hp, which is where you want it to hold steady throughout a long pull to achieve the greatest top speed.
 
LaPorte429 said:
I believe you want the clutches to allow the engine to immediately go to the rpm where it makes the most torque and then climb to the shift rpm where it makes the most hp, which is where you want it to hold steady throughout a long pull to achieve the greatest top speed.
Click to expand...
;)! 3:16 (YAMMIE TONY)
 
So my understanding is that a stock viper will make it's most torque at 8500 to 8600 rpm. I'm wondering where it makes the most hp?

My manual doesn't address torque and hp in explaining the shift speed but it does say this:

"Normally, when a machine reaches shifting speed, the vehicle speed will increase but the engine speed remains nearly constant. Under unfavorable conditions (wet snow, icy snow, hills, or rough terrain), however, engine speed may decrease after the shifting speed has been reached."

I'm also not sure if a mountain sled needs a set up based on a slightly different principle to make more torque rather then hp since it's really trying to move snow more than go fast.

I do know that my mountain viper that is set up right ( at least I think it is) will do about 85 - 90 mph on a long pull. Usually 85 ish but with a slight decline i've hit over 90. Slow for you flatlanders...lol But just the same the mtn sleds are more of a tractor the way I look at it.

Thanks for the help. I really don't know much about clutching. This is my first go at it.
 
So according to graph, the Viper should race to 8550 and stay there throughout shift? That is what was not described in previous posts.

Confusing.

"I believe you want the clutches to allow the engine to immediately go to the rpm where it makes the most torque and then climb to the shift rpm where it makes the most hp, which is where you want it to hold steady throughout a long pull to achieve the greatest top speed."
 
SRX 700, that's what it looks like to me. Clutching to me is a new concept so I'm not sure how much my opinion means. However that chart sort of jives with what my yamaha manual says:

"Normally, when a machine reaches shifting speed, the vehicle speed will increase but the engine speed remains nearly constant. Under unfavorable conditions (wet snow, icy snow, hills, or rough terrain), however, engine speed may decrease after the shifting speed has been reached."

The above quote is from the clutching section.

So I suppose that's what I'm going to shoot for.
 
On a side note, what is the best method for cleaning a clutch. I've read to not use any solvents. So do you just use soapy water, or just an air hose?
 
Just warm, soapy water. You don't want any solvents staying on the clutch. I use warm soapy water with a green scotch brite pad, and use circular motions on the clutch faces. The scotch-brite pad will leave the circular marks after you are done. Several people even put them in the dish washer, while the wife is away of course, lol.

I do use air to blow belt dust out of the primary about every third ride or so, only pull it off once at the beginning of the season. The secondary I may take off two or three times, depending on how much riding I'm getting in.
 
mod-it said:
Several people even put them in the dish washer, while the wife is away of course, lol.
Click to expand...
ive done this method before. it works... but i got busted.. and am now banned from the dish washer. she noticed some black grime around the door, that i didnt see. she freaked out and asked me what the hell i was doing with the dish washer... it didnt go very good. lol :hide:
 
I washed both my primary and secondary using the dishwasher at my work cafeteria. Needless to say, I work for myself now. :dunno: :dunno: :dunno:
 
Well, I do have access to the dishwasher. I may be able to pull that one off!

:hide:
 
you have to train your better halves to accept it.I have used DW to clean clutch's.my wife doesn't care.I have used the oven to heat treat the paint on my exhaust pipe..now that was a little different as the smell from the paint really annoyed her..but told her not to worry..everything was under control.
 
the torque throws the sled out hp holds it.in a perfect world it should start out at 8200 and finish at 8500 thats how i set them up and the fly
 
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