I posted on another post today about how to lighten the clutch on a v-force or p650. You do this by drilling holes in the face plate of the clutch. Next I said you could remove cooling fans on the back of the clutch itself.

Drilling holes in the face plate is easy, 8 1/2 inch holes, drilled on the outer part of the clutch, it'll raise your RPM's by about 500. I'll post pictures tomorrow night on my pic page.

Removing fins is a different story, if you remove fins you had better have heavier clutch weights. You'll be removeing alot of weight, your RPM's will go against the rev limitor and you won't be able to get them down with out heavier clutch weights, which aren't out yet.

I use adjustable clutch weights, I can add weight to mine. After lighten the clutch you'll need to adjust your clutching, just as you would rejet after putting on a modded pipe.

Please don't do the fin mod unless you know what your doing. Make any modds at your own risk, They work for me, they might not for you!

I felt I needed to post this after receiving several PM's with people saying they were going to do it. I would be glad to help anyone who needs help!

 

SHOTGUN... I currently like to compete in very different arenas with my ATV... for the extremes, I run a set of 28" X 8" X 12" Mudzillas for mud bog racing ( finishing 1st in the mud bogs comes easy to me, as I raced Jeeps for years ), then drop to a set of 22" X 12.5" X 9" rear tires for Hare scramble races ( haven't done real well here yet ( room for growth )) ... not being an expert on clutching, but not ignorant either, I intend to set up seperate primary & secondary clutch baskets with weights, & springs best suited for the 2 extremes that I run in tires... my thought was that it would be easier to change out the entire clutch assembly, rather than disassembling each every time...I'm a bit hesitant to remove cooling fins, as I abuse my quad for 90 - 120 minutes during hare scrambles, & intend on racing the 12 hour enduance race in Fort Dodge, Iowa in October...however, I respect your opinion in regards to setting up these clutch assemblies... I have an apointment with a CVT clutch specialist for next week, and having a couple of opinions before hand wouldn't hurt, thanks...WAM

 

Newbeatle;

Well I'm far from a expert on clutching, but from years of snowmoble racing and four wheel pulling, you soon become self taught. One thing I quick found out is snowmoble is not the same as ATV's.

I agree that you need two completely different setups. two different clutches would surely be the easy way to go.

I would think that lighten the clutch would serve you well in both cases. It would let you get your rpm back up to get horse power for the mud runs and let your rev quickly on the hare scranble, coming out of the corners.

After lighten of the clutch for the mud runs, you could go with heavier weights for less slippage.

Lighten for the scramble, would let you also us heavier weights, but not as heavy as for the mud. The only thing I would suggust is to by weights with more curve to them than stock for the hare scramble. This would let you pull stronger in the mid range where you be a big percentage of the time.

Don't remove your cooling fins, for what your doing.

 

SHOTGUN... Have you got a better description or pictures of the holes you're drilling ??? ... How about suggestions of where to start for weights??? I was thinking about EPI 52 gram for the small tires, & 56 gram ( or 2 - 54 gram, & 2 - 56 gram ) for the big tires...How about springs, I'm still running the stock springs, I could see the black secondary spring for the big tire set up, but don't want to loose any more top end with the small tire set up... I was thinking of adding a shim to the spring ( giving me more tension to start with, but not more pressure through out the range ( to keep from limiting the top speed ), for the small tire set up...I'm currently running the 360 belt, I may just go ahead & order the 700 belt ( I like the shape better than the 360 & 650 )... in my last mud bog race ( took 1st place in the large bore open class ), I smoked my 360 belt a little, coming out of the pit ( sticky clay, I was the only one to make it through the pit in my class, so they had to rework it )...I couldn't even turn over the tires, they were so heavy with sticky clay, so some clutch work is definately in order... I'd like my quad as versitile as possible, & would also like to try some pulls, & ice racing this next year... thanks for the info...if you want to e-mail some pics, etc... you could e-mail me at

mwalker@smig.net

thanks...WAM

 

This sounds very interesting, but will it weaken the part any when I drill the holes in it? Does the removal of fins have any effect on the air flow to the belt? I just want to play it safe, I've heard that when a CVT fails, it can lodge parts in the belt and lock up the rear. Any suggestions?

 

Newbeatle,
I'll email you.

prairie633,
Don't remove any fins, just drill the holes, I'll post a pic of what I did on my pic page tonight. In my opinion there not much risk of weakening the plate with the 8 holes, but you have to make up your own mind, rather it's worth it or not.

Before anybodys removes fins, they need to know what they are going to use for heavier clutch weights because their RPM's will go out of site, like using nitrous. Will have to have weights near 75gms to bring the back down.

I can do this, I have adjustable clutch weights, I know of no one else that have them.

 

I would guess that selectively drilling holes will not significantly weaken the clutch ( look at drilled disk brakes )...but may possibly reduce the torque a little, if the moving part ( attached to the shaft, acts like a fly wheel ) of the clutch is lightened, it should have no negitive effect ( & may have a positive effect ), on the torque if the non moving part is lightened ... WAM

 

check out my pic page, I've posted in my pictures where I drilled.

Might take a while, I think they have to be approved first.