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I finally got my old helix apart and am installing an EPI clutch kit on an mxz 670. I was wondering I already put it together quite possibly wrong and when I installed the new helix it snapped all the ramps. What direction do I preload the clutch? Also I just ordered the secondary puller to get a preload spec what should I expect? This is a trail sled hopefully a little more. I also ordered the skidoo puller to hook a secondary up to a spring scale. Please help I would really really like to wake this sled up. Also I am rebuilding with wiseco complete kit any suggestions??? Thanks
 

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journeyman sled/motorhead
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I finally got my old helix apart and am installing an EPI clutch kit on an mxz 670. I was wondering I already put it together quite possibly wrong and when I installed the new helix it snapped all the ramps. What direction do I preload the clutch? Also I just ordered the secondary puller to get a preload spec what should I expect? This is a trail sled hopefully a little more. I also ordered the skidoo puller to hook a secondary up to a spring scale. Please help I would really really like to wake this sled up. Also I am rebuilding with wiseco complete kit any suggestions??? Thanks[/b]
been to long since I had a 670. but welcome. I TD has some help for you if not I will doo some research and find out what I ran in mine.
 

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its wound counter clockwise when you assemble it. if all your ramps were brocken ya might of squished it together right on top of them. i spin theclutch half, hold it and then squish the helix in. if it stops before its in then your in the wrong spot.
 

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Discussion Starter #4
The helix went in very easy until the very end when I was making room for the snap ring. It all went together fairly easily and it even seemed to have about the right preload then when I spreaded the clutch apart as I was unscrewing the tool to spread it, the clutch got stuck and then it kinda fell apart in the inside. I really have no idea what happened it was very wierd. How far do I need to twist the clutch as it is being put together?





its wound counter clockwise when you assemble it. if all your ramps were brocken ya might of squished it together right on top of them. i spin theclutch half, hold it and then squish the helix in. if it stops before its in then your in the wrong spot.[/b]
 

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The driven pulley should have a 504141800 Washer installed on the outside of the cam (helix) before the snap ring is installed (Ski Doo cams have a steel hub) so it doesn't chew up the aluminium EPI cam. A little bit of anti seize or grease should be applied to the inside bore of the new cam. Depending on the spring installed on the driven clutch (Ski Doo Beige) or EPI blue, start spring placement at A5 (C=softest A=intermediate and B=stiffest).Your goal here is to get an average of 19 lbs measured at the outer circumference of the sliding pulley half. With the scale in place pull it until the pulley moves 1" observe scale (eg. 21 lbs), slowly release the pull on the scale until the point at which the pulley rotates back and observe the scale (eg. 17 lbs). Your average is now 19 lbs. Keep in mind tightening the preload will slow down your up-shift and quicken back-shift while loosening preload will quicken up-shift and slow down back-shifting. If your kit didn't come with new TRA ramps, you might want to consider some 417005280 ramps as they really wake up the hole shot on packed snow. The stock 286 ramps are pretty good all around otherwise. If your primary is using an EPI yellow spring (240-320 lbs), set your adjustable pins to 18.2 grams (2 short hex screws). be sure to use OEM buttons in the primary (used ones) are just fine. Lube the sliding parts with Non stick table saw dry lube and make sure you use a new 417300067 Ski Doo belt. Set the pulley distance up with the engine idling and rear end lifted. With distance correct, the track should just start to creep off the ground. I wouldn't bother putting the windage plates back on the secondary either unless ultimate top speed is your goal. The cooling benefits with the plates off pays bigger dividends. Your shooting for 7850 ~ 7950 rpm and no more as power drops off fast on a 670. Set the clickers to # 4 to get a base line. I would also suggest changing your gearing from stock 26 - 44 to 26 - 42 because the 670 loves to be loaded down to optimize it's big flat torque band. Lastly, let your track limiter straps out 1 hole, tighten ski shocks 1 notch before max (depending on your weight I'm 225 with gear on) and hang on !
 

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If you have the motor apart, let me know. I can give you some sound advice to make play more fun.
 

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you note he says " a little anti seize or greese". I will say this a little goes a long way. I say the 280 ramps.
 

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Discussion Starter #8
Wow quite the info, where can I get a different sprocket? Is there a part number?




you note he says " a little anti seize or greese". I will say this a little goes a long way. I say the 280 ramps.[/b]
 

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Discussion Starter #9
Does anyone know where to get the hook to check the secondary spring tension? I tried the part number skidoo gives in my manual but just got an email today that it is discontinued. Has anyone ever made this tool? Is there another part number?
 

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The scale hook can be fashioned from a plate of steel or aluminium with the scale hook hole close to the outer circumference of the sliding half pulley.

[attachment=39990:Clutch_t...on_plate.jpg]

Remove the windage plate from your secondary (if equipped).

[attachment=39991:Remove_w...ge_plate.jpg]

Align slot in hook plate with reinforcement rib on pulley.

[attachment=39992:plate_mounted.jpg]

Lock it down using one of the windage plate retaining screws and Bobs your uncle. If there's no factory windage plate you'll need to carefully drill a 3/32" hole into one of the casting bosses then tap it with a 1/4" X 20 threads per inch tap. Be careful not drill too deep into the boss and use a bottoming tap.

[attachment=39998:plate_installed.jpg]

PM me your mailing address and I'll send you a home brew tool I made.
 

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Discussion Starter #12
If I change the sprocket do I also need to get another chain or is it so minimal that the tensioner can account for the different sizes?
 

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If I change the sprocket do I also need to get another chain or is it so minimal that the tensioner can account for the different sizes?[/b]
The 74 link chain should be fine as long as it's not stretched beyond spec. You verify it just like an automotive timing chain.
 

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Discussion Starter #14
Will the 43 tooth sprocket work just as well as the 42 or should I try to find the 42? Have you ever used a 43? Also will I lose a lot of top end with this sprocket or will this not affect it? Thanks for all your info TD.
 

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Discussion Starter #15
Also how do I know if the adjustable pins are at 18.2 grams? Do I need to weigh them with a postage scale or is there so form of markings?
 

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Will the 43 tooth sprocket work just as well as the 42 or should I try to find the 42? Have you ever used a 43? Also will I lose a lot of top end with this sprocket or will this not affect it? Thanks for all your info TD.[/b]
No one I know makes a 42 tootth 13 wide anymore so it's going to help the accelleration and top end more than the stock 44 tooth unit
Also how do I know if the adjustable pins are at 18.2 grams? Do I need to weigh them with a postage scale or is there so form of markings?[/b]
The EPI pins plus 2 short screws should weigh 18.2 grams. Take one to the post office to check.
 

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Discussion Starter #17
I found a 42x13 at dennis kirk so I am going to order that I believe, also my kit only came with a helix and two springs so there are no pins. Is this going to be a problem. I really want to do this right the first time so I am trying to get all the info figured out. Out of the two gears you have had the best luck with the 42, right? Should there be adjustable pins with the kit or is that only for certain sleds. Thanks
 

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I found a 42x13 at dennis kirk so I am going to order that I believe, also my kit only came with a helix and two springs so there are no pins. Is this going to be a problem. I really want to do this right the first time so I am trying to get all the info figured out. Out of the two gears you have had the best luck with the 42, right? Should there be adjustable pins with the kit or is that only for certain sleds. Thanks[/b]
Great, you found a 42 tooth gear. Goodwin also still stock 42 gears in steel Usually clutch kits have adjustable pins with them to fine tune the rotating weight hence the up shift characteristics. According to EPI's site they don't provide pins with their cluttch kits. I checked with Goodwin Performance and they sell adjustable pin kits for the 13.6 to 18.9 gram range. http://www.goodwinperformance.com/skidooclutches.asp
Your stock solid pins 417 004 308 should weigh 16.4 grams.
 

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Discussion Starter #19
Is there a big difference in using the 18.2 gram pins rather then the stock 16.4? I see I can order just the adjustable pins from goodwin. Thanks for all your help..
 

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Is there a big difference in using the 18.2 gram pins rather then the stock 16.4? I see I can order just the adjustable pins from goodwin. Thanks for all your help..[/b]
It enables you to fine tune the launch and up shifting characteristics more precisely. Why don't you just install the clutch kit as per EPI instructions annd see whether you want to improve later.
 
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