Clutch Tuning, Primery Clutch Spring

Sep 28, 2010 | 06:02 AM

#21

ftwflh

Quad Patrol
Don't let the hp numbers fool you. Its all in how you get it to the ground. Clutching clutching clutching!

Joined: Apr 2000

Posts: 6,688

Likes: 1

Quote:

Originally Posted by WaaHeHe94

Have you done any mods to the exhaust or air intake system?I wouldn't really change the clutching if I was going to do any mods in the future and then have to invest in a new primary and secondary clutch along with maybe a new helix and weights to go along with new mods.

With that being said I have spent a lot of time testing different primary and secondary clutch springs, weights as well as different secondary clutches on my Sport 400 that I dragrace.I currently own a Team Roller Secondary, an Aaen Roller Secondary and a factory Polaris Secondary with HPD Super Buttons.Just for the record the secondary that I have chosen to run with is the Team Roller Secondary.After several years of testing and spending way too much money just to gain a couple of 10ths of a second in the 1/8th mile I can tell you that what works for one person will not always work for another.

The most common mistakes that I see from people as well as vendors is using a primary with too high of a shift RPM and using weights that are too heavy.About the best advice that I can give on clutching is to invest in several different primary clutch springs, get a good tach and spend some time at your local IHRA or NHRA dragstrip and compare 60', 330', 660' and MPH times with the different primary springs.

I know this isn't really a good answer to your question, but without knowing what your mods are then it's really tough to even guess where to start at with your clutching.

Here's a video of my Sport 400 at the local IHRA dragstrip where I bracket race in an ATV Bracket Series.My 61 year old father is on the Sport in this video and my primary spring is an EPI orange spring for a snowmobile with a Team Roller Secondary.This pass is on the motor, when I race it I use a 20hp shot of Nitrous Oxide.
YouTube - Sport 400 Primary Spring Testing

Good info..............but clutching a trail machine is a little different.You have to get set to work right in ALL situations.Also clutching a 4stroke is not as critical as is on a 2stroke.4stoke clutching is more like what underwear you have.More personal prefferance than having to be dead on.

Sep 28, 2010 | 01:36 PM

#22

WaaHeHe94

Range Rover

Joined: Nov 2004

Posts: 191

Likes: 0

Quote:

Originally Posted by racer37l

WaaHeHe94, how close to elk creek do you live? I live just above Bluefield.

I live in Marion, Va about 40 minutes from Elk Creek.I usually race there 2-3 times a month on my 4-wheeler in the 4-wheeler class, the motorcycle class on saturdays and sometimes a Test & Tune session on friday nights.Last year they changed the rules to allow ATV's to race in the motorcycle class as long as you run 9.99 or faster.

Bristol Dragway in Tennessee, which is an NHRA track also allows ATV's and SXS's to dragrace in the motorcycle class and on thursday nights in their Street Fight Series.

There is going to be an ATV and MX dirt-drag in Mountain City Tn this saturday.If you're interested in going sign-up starts at 5:00 PM, Test & Tune from 6-7 PM and racing starts at 7:30 PM.The GPS address is 5276 Highway 67 West, Mountain City, TN 37683.The two phone numbers on the flyer are 1-276-676-2881 and 1-423-967-4785.This is the first time that I've been to a dirt dragrace and raced at Mountain City so it should be interesting.

Sep 28, 2010 | 01:55 PM

#23

WaaHeHe94

Range Rover

Joined: Nov 2004

Posts: 191

Likes: 0

Quote:

Originally Posted by ftwflh

I've gotten some experience clutching 4-strokes as well.This is the Sportsman 400 that I race at our local County Fair ATV Rodeo's, dragrace occassionaly and switch tires and trail ride 90% of the time.

Clutching really isn't that hard as long as you have a way to accurately measure your data and results.When I first started trying to clutch my own ATV's I made mistakes just because there is a lot of bad and inaccurate information out there about clutching.The most common mistakes that I see are people have too high of a shiftout rate and too heavy weights.Both of those will seriously hurt your top end performance and speed.

YouTube - Sportsman400

Sep 28, 2010 | 08:31 PM

#24

ftwflh

Quad Patrol
Don't let the hp numbers fool you. Its all in how you get it to the ground. Clutching clutching clutching!

Joined: Apr 2000

Posts: 6,688

Likes: 1

I totally agree with you on that.I tune 4strokes for good mid range power for trails.
Like on my 500 Scrambler I run a Polaris yellow primary spring,TEAM roller secondary with a steep helix (44-40) a light spring (blk/yellow) and now I have a set of 10AL (54grm) weights.Get performance with top RPM of 6500.Was running 10RH (50 grm) but top rpm was a little high at 6750.Did excel faster but I feel safer with the lower top RPM.