[madcow]

[] ok guys here we go. first my goal is that we walk away from here with a good understanding about clutching and its components. lets say you have already went through your sled for general maintenance, track alignment, chain tension, and track tension.

now lets start with the primary clutch.

the primary clutch has the wieghts and a spring, the wieghts shift it up and the spring shifts it down. it is an rpm sensing clutch that means all it reacts to is rpms.
lets build a theoreticall kit, the parts and rpms are just for example but i will try to be close.

I went up town and bought a used 2002xc700. I am going to show up my buddys 800.
I look at the stock wieghts and see that they are 60 grams with a lot of wieght at the pin and the middle, than gets thinner as we move to the tip. I go and put in some 62 gram wieghts with more of a straight profile, lots of mass at the pin but it doesnt get thinner, now this is wieght profile, where the mass is in the wieght, is where it will pull harder, as the stock wieght tapers off so does the pull, on the new weight it has a straight profile so it will pull the same as the other but since it has more mass at the tip it pulls harder on top end, now we add in the extra 2 grams of wieght, the engagement stock was at 4500, now it is closer to 4200, we take it out for a run, punch it starts to spin for a second than can barly get moving and lugs around 7000 wide open instead of 8200. the wieghts pulled the rpms down because they are making the clutch shift up faster. We go the the book and our stock spring is 140-330. what this tells us is that at engagement the stock wieghts overcame the force of the 140 lbs of spring force at 4500 rpm, but the new wieghts over came the spring at 4200rpm, same at wide open throttle, the stock wieghts with 330 lbs of spring force made a shift rate at 8200rpm, but the new wieghts overcame the spring at 7000rpm.
so now we get a new spring, so lets try a 150-350. lets say this now gets us back to the 4500-8200. but now our rpm are the same but it should be pulling a little harder with a pile of more top end pull.
so you can see that if you just change one thing it totally changes everything.
you can also see how the wieghts open the clutch, the more wieght the faster the clutch opens. thats were the primary spring comes in, once you have your wieghts, just get a spring to set engagement and help set wide open throttle rpm.
lets just stay on primary and see what i didnt make clear enough. then after a couple days we will move to the secondary.

 

[EDGEX Rush]

ok i understand that but what if your talking radar runs where you dont want a high engagment but more top end. also what would happen if for say you had stock 58g and you kept the same weight and changed where the weight was dispalced on the weight.would you just make a fine spring adjustment and still gain more top end. this is going to be some real good knowledge for me thanks madcow.

 

[madcow]

if you left every thing else stock but went to a more aggressive 58g you would have some gain.
for speed running you want to bring that engagement down low so you would get like a 100 330 or 80 =280. for speed running I have found that with all else the same just bringing down the engagement has increased speed. i use a polaris gold with 62-66 grams she comes on at 2800-3200. If you are looking for serious gains for speed running you have to regear for the speed you want to hit. lot of chassis tunning and then I like to set up the primary clutch to pull the rpms down and engage were I want, then i use the secondary to get to the fine tunning, i run a helix with several spring to see what the speed and rpm are doing and go from there. the less helix and less secondary spring the faster you will go.

 

[EDGEX Rush]

so if i have a 120-310 with 10-58 weights i should be looking for like maybe a agressive 64g weight and a 78-240 primary spring and if gearing is 23-39 i should go to like 25-39 or what im getting the clutching what about the gearing should i go up on the top and go down on the bottom or should i just go up on the top.

 

[madcow]

gearing depends on the distance. for that sled in the 1000' My best guess would be something close to a 23-39, mark the clutchs if you get close to the speeds you want and see that you are shifting out, then bump up one notch on gearing. If this was my sled, for speed running I would stay closer to a aggressive 60g, try that 78-240 get down to the straight 32and 34and 36 degree helixs, and then play with the blue, silver, black and red secondary springs, you will be faster in mph if you went with the 32 helix and red secondary. all springs in the first or softest hole, you dont care about back shift. you want to come off the line at a low rpm so it may take 10 feet of roll out then she will rev up quick and off it goes. dont try to gear to high, you will have a harder time building speed. I help some guys up north with there 600 and for me they are geared a little to high, but they do all right.

 

[EDGEX Rush]

ok madcow im good on the primary stuff im ready for your next step in clutching. you have already helped my understanding alot. thanks

 

[madcow]

ok, good, on the secondary the helix upshifts and the spring, back shifts. on the polaris clutchs the less helix angle you have the less compression rate from the spring you need because the lower the angle the more natural belt squeeze, the higher the agle the more spring you need to help hold the belt and also backshift. if you have a 50-34 helix with the silver blue spring, and you drop to a 46-34 helix, you might be able to get by with a silver or black spring, and for sure a blue one, but you will have gained a quicker upshift, because the primary clutch has less spring to fight. on the secondary spring you have two ratings compression and the twisting rate, compression holds the clutch together and twist does most of the backshifting. personaly i like the low straight angle helixs better. you get like a straight 34or 36 run the blue or even drop to black or silver, but i think blue would be best for trail. and you would have a sled that would have awsome backshift with little spring force so changing belts would be a dream. it doesnt give such a hard snap on acceleration but it is smooth and fast, the higher the angle with more spring pressure is a quicker setup, but usually slower in mph. this is were i think the team clutch is a gimmick. if you really want a roller clutch go get an artic cat clutch and put it on. you have to balance what you want. if you want to sping a whole on the starting line and have a snappy clutching that sacrifices upshift speed go with higher helix angle and more spring. if you want a snappy machine that pulls more on top go down a little on angle and a lot on spring. if you compare springs. you can take your silver blue out and drop in a blue spring. the blue spring has less compression rate for a quicker upshift. but more twist rate for a good backshift, you might notice that the tach stock when you punched it would just jump to 8200, now with a good agressive clutch kit you punch it on the trail and it jumps to 8000 than takes a couple seconds to reach that last 200 rpm.

 

[EDGEX Rush]

ok i am woundering if your useing my number for the 600 or are these your 700 number just for an example. but i think i understand this. if you want a radar set-up go with a stright low angle helix (ex.32, 34, 36) with little spring pressure and if you were doing grass drags you would want a stright high angle helix (ex.52,54,56)with more spring pressure, and for trial riding you would want a dual angle helix like (ex.stock 50-34 change to 52-32)with medium spring pressure. when high angle you are saying something like 54 am i correct.

 

[EDGEX Rush]

also if this is correct why would more pressure on the secondary spring if you are grass draging wouldnt this hold out the belt shifting? i thought you want a quick shift.

 

[xc700_02]

Well Ive re-read this thread a few times today... Im learning

Dont rush please!

Let me inhale the info over night....

 

[madcow]

yes you want a quickshift, but for quickness not mph a little more helix angle and spring can some times do the trick. if i try grass this summer i will stick with my smaller helixs. for trail sleds it is more true. for racing your frame set up and gearing for the distance has such a huge play in winning or losing, so does time to practice. once you start playing with clutching and race setup, at first you might go slower than stock until you get yourself some time. also the stock sleds do ok with stiff secondary because they only shift a little bit because they are geared for trail. that clutching with low grass gearing would get you nowhere fast. you would have that pop open a little ways and then not gain much speed.

 

[EDGEX Rush]

ok thanks so i you do grass drags this summer you would go with a stright lowangle helix with little spring pressure. i was woundering if you knew what the blue Epi springs specs. were i was runnning this last year in the grass and i think it was a good spring but i want to try im proving on this set up this but i dont know what the specs are on it.

 

[madcow]

I will try to find them out, remember, there is no absolute correct way. just some better than others. you should have about 3-4 helixs that are close than a couple sets of wieghts, couple primary springs, several secondary springs. as you change from day to day you will start to notice a kit that you keep tunning around. set up the primary than pick a helix and fine tune with a seconadary spring, try another helix and so on.

 

[EDGEX Rush]

madcow i just want to make sure that the weights with the H after them are the agressive ones from polaris.

 

[p-triple]

Hey fanatics p-triple here. Good job on the clutching stuff. I have learned a few things reading down through your posts. I have a piped 680 ultra and was wondering about some drag racing clutch set ups. I am currently running 23-41 gears and 10-56 wieghts. Now, triples have always been known for having more top end. Polaris 10 series wieghts are the most convenient for me to run. Does this mean I can make the mid to top end shift more aggressive with a steeper helix? If so what would be a good second angle on the helix. Right now I am trying to pull a 48-36 full progressive. Or should I find a heavier tipped wieght. I hope I am not jumping too far ahead for you guys.

 

[Darkstar]

You are certainly not jumping ahead of Madcow, He will respond with info I am sure.

 

[madcow]

you are trying for drags right? first off you should look at the clutching you have, mark them, and then run the distance of the track. see how close to the top are you running. for drags you can get by with lower gearing. you could drop you top sprocket closer to 21 and get by i bet.
and yes for drag i would go with lighter wieghts and more helix. the polaris silver blue secondary is a good drag spring.
for racing it is a try and see aproach. get some measuring equipment to see if you are making gains or not. you could then try some 10-54's heck i would get down to some 47 and 50 gram wieghts, with 52-36 helixs with a polaris blue or something close to that for a primary spring.

by getting the weights down you let the motor spool up quicker, and then the big helix will do the shift out.

also if you have trail heads, get some 98 or 105 vp fuel, then you will be able to jet way way way down, even on real cold days. especially if you are only going 660 feet. I know of ultras running 320 mains spinning 9200 rpm for the 1000 foot speed runs.

 

[p-triple]

Well madcow thanks for the imput. I origanlly started with 19-39 gearing but some experienced racers told me that was way too low. However, I personally think I was closer with that gearing. I forgot what the speed was but I think this year I will start off with 95-100 mph gearing and work from there. When I started off though with the 19-39 gearing I couldn't pull a 52 36 helix. Even with 10-54 wieghts and a blue orange secodary spring. Anyhow I think I have a strong grasp on clutching. I have just got to go out and apply it and see what works the best.

 

[madcow]

yep, test and test and test. if that gearing will get you to 95-100 mark, that is close to where you want to be. improve stock 700 in 660 should be in the 100 mark.. riley did 92 in 500 feet.

to pull the bigger helix you will have to drop in lighter wieghts.

some clutch setups do better with more gearing and others do better at getting to overdrive. all you can do is test.

good luck.

 

[p-triple]

Well I calculated my mph with the setup that I have now and it is too high. I am running somewhere around 102 at l:1 clutch ratio. I am going to drop it to 21/39 for the start of this season. That will be around 98mph at 1:1. If I remember right though don't the clutches exceed 1:1 ratio at full shift out? If so would you happen to know what that is? Also when I had my sled geared 19/39 there was a little to much ski lift. should I gear up to get ski lift right or loosen my belt tension. That is if the 21/39 gearing does the same thing