Clutching

[IZZ]

Ok I got my 800 rocket ripping around the yard for testing now. It runs awesome!
750 PSI quads - .039 raised cylinders - .032 off the heads for 142psi - bored the piston port holes to 3/4" - carbon fiber reeds - spacers - gutted (custom) airbox - everything I could think to do short of overboring the cylinders and cylinder porting. This thing is FAST! WOW!

Now I dont know 1 thing about clutching a snowmobile. I managed to figure out how to remove the secondary, take it apart, clean it, and replace the silver code secondary with a brand new one and install the 49/43 helix (thanks yammiegod) I rigged up a way to pull the plate off the primary and changed the spring to a hauck blue. (thanks again) but I dont have a way to or dont know how to go any farther than this (weights or changing bushings or removing it to clean and stuff) I dont have a puller or anything else clutch tool related.

I want to get this clutch right, but I think Im gonna pay to have it done because I dont have much time currently to work on it, unless someone has a convincing way or reason to do otherwise?

I marked the primary with permanent marker like I read on a post before to see if it was getting full shift out, even though I dont know why this is important or exactly what I was doing, but I tried never the less - I put it on a stand and revved it to like 8600rpm and theres still about a 1/4" of marker left. Than I ran it around the yard for several full throttle stand it up blasts and still about 1/4" of marker left. Why? what does this mean? and how is this remedied?

ON stand the track begins to move at 3900 - 4000rpm, on the ground the sled moves away under its own power at about 4200 - 4300 rpms (this all on the factory tach) now what is the accurate way to gauge engagement speed? Yammiegod, I know this clutch setup you recommend should engage at 4500, so how is this adjusted? or do I even need to for a trail riding, lake racing, hybrid application?

3rdly, Like I said Im running 750 modblasters on this 800, and Ive read that you need to keep your rpms matched to your pipes power curve. So these things peak at 8350 I believe anyway, does that mean I need to make an adjustment to limit the sled to revving to 8350 only then? If so how do you do this? is this where the weights come in to play?
Right now this thing easily hit 8600 on a stand and would love to go higher I just chickened out and wouldnt give it anymore juice.

So anyway Im thinking I should just just take it in for now and have it setup. Any ideas on how I lay it out to the mechanic?

Also I have a bender orange spring - a 52/42 helix - a new set of 8bu-00's - and a set of 17.2 rivets to play with as well if you think Id be better off with any of it instead.

[RDL 93 V-MAX4]

Awesome Toque IZZ and it stayed on your head....LOL!!!!!!

[Master of Faster]

That 1/4" of marker is about normal. Yamaha clutches will not shift out fully so that is fine.

Yes, you need to limit the RPM of the motor to where it makes its power at, and yes, that is what the weights do.

More weight = faster shift = less rpm
Less weight = slower shift = more rpm

Just any sled mechanic is not going to be able to clutch your sled properly. If it were me I would start with those 8BU weights and load both holes with the 17.2 rivets. I'd run a blue hauck primary for trail riding or a black for a combination of trail and lake racing. Engagement can be adjusted slighty using engagement shims (they're like washers that go under the primary spring). I'm not sure what a Bender orange spring is, maybe that will be good, have to check. Run whatever spring/helix Yammiegod suggested to you. Then take it out, see what ya got, and report back.

I'm sure Yammiegod or others can give you even better suggestions, and there is nothing better than doing it yourself, look what you've done already!

[YAMMIEGOD 3:16]

DUDE, DON,T TAKE YOUR SLED ANYWHERE FOR CLUTCH WORK. SECOND YOU DON,T NEED TO OVER REV IT AT 8600 ON THE JACKSTAND. FROM YOUR PICTURES EVERYTHING CAN BE CHANGED RIGHT THERE. I,LL WALK YA THROUGH THIS. I DO HAVE ONE QUESTION, YOU HAVE 750 QUADS ON YOUR 800 ? AND WHAT RPM ARE YOU AT WHEN RIDING IT, NOT JACKSTAND !! I BELIEVE THE 750 PSI QUADS RUN AT 8350. ! 3:16 (tony)

[IZZ]

Master and Tony, thanks for the info! Please respond to the following. Im trying to get this whole clutch theory down and would like to know if Im on track.

That weight vs. RPM makes sense to me somehow, that the heavier the weights being flung out would kinda slow the motor down a bit. And it probably helps to squeeze the belt harder maybe?

But Im a bit lost on the weight of the weights affecting shift. Is it like this - The heavier the weights the lower the rpm required to fling them out with enough force to counter act the primary spring and engage the clutch and vice versa? If so this would mean that the rpm's you select to run at would determine what weight of weights to use. Then the engagement RPM you select to engage at would determine what primary spring to use (since the weights push against the spring (through the spider of course) the whole spring stiffness thing would be to delay or increase the rpms required to engage the clutch by counteracting the force of your chosen weight) for example a stiffer spring or more engagement shims would delay engagement and a weaker spring would engage sooner.

Please tell me If Im on the right track or the right train for that matter.



Tony, 750 quads were all I could come up with and I had to buy a whole sled for them!
From what I understand theyre supposed to run at 8350 also. But man I dont even know what that means really like I said above. Am I supposed to set up clutches so thats all the motor will ever rev to when Im riding it?
And when you ask what r's Im at when riding it do you mean If I was to have an unlimited straight way what would the tach peg out at?

Sorry if I sound stupid, but Iam when it comes to this clutch/shifting stuff. I hope youll still be willing to help me out with this?

Thanks

[Master of Faster]

IZZ you are definitely on the right track man, everything you said was correct.

Heavier weights create more force when spinning at x rpm therefore shifting or closing the primary clutch faster bringing your rpms down. (think of it like shifting into the next higher gear, when you shift into a higher gear in your car, you go faster and your rpms come down, the quicker you shift, the lower you keep the r's, the longer you hold without shifting the higher the r's, the goal is to shift your sled so that it stays right where your max power is, 8350rpm in your case)

You are also correct that the primary spring opposes the primary weights. Heavier spring = slower shift = more rpm

Basic clutching is to select the primary spring you desire to achieve the engagement you're looking for, then add or subtract weight to achieve the desired rpms.

There are tons of different things to consider like placement of weight on the weights, weight profiles, roller sizes, helix angles, secondary springs and so on but it sounds like you're getting a good grasp on it.

Clutching your own sled (with helps of others on here) is deffinitely something you should do, you'll learn a ton about it that way.

[jminor]

Buy a clutch puller!! Best $20 bucks you'll ever spend! I've also just bought a clutch compression tool so I can play with the weights on the machine...now if I can figure out how to use it!

[YAMMIEGOD 3:16]

DUDE, YOUR BASISLY ON TRACK. IF YA LOOK AT THE BASIS, REMEBER THIS.
PRIMARY SPRING- CONTROLS ENGAGEMENT. IT ALSO WILL AFFECT YOUR TOP RPM. NOW YOUR WEIGHTS, AND THEIR WEIGHT IN GRAMS AND ROLLERS WILL ALSO AFFECT THIS. THIS IS THAT 8350 NUMBER YOU TALKED ABOUT. NOW, YOU CAN FINE TUNE YOUR ENGAGEMENT TO A POINT. YOU DO THIS WITH EITHER A STIFFER SPRING, CORRECT TERM IS MORE PRE-LOAD (stiffer spring) AND OR PLACEING SHIMS IN CAP OR COVER. NOW YOUR HELIX CONTROLS HOW FAST YOUR CLUTCHES SHIFT. VERY INPORTANT TO REMEBER, ALL THESE THINGS HAVE TO BE RIGHT. YOU MUST RUN THE TOP RPM THESE PIPES ARE DESIGNED TO RUN AT. SPINING AT 8650 WITH 8350 RPM PIPES IS A WASTE OF TIME. ALSO ANY CHANGES YOU MAKE, IT AFFECT YOUR ENGINES PERFORMANCE. THATS WHY I TRY TO GET PEOPLE CLOSE AS POSSIBLE WITH BOLT IN CLUTCHING. 3:16 (tony)

[Turk]

primary spring terms....preload=length of spring=engagement
total force=thickness of coils=rpm,s of sled at throttle. Basically longer spring=higher engagement. Thicker spring=higher rpm,s. Buy Aaens clutching hand book & read it a kazillion times. Good info in there & covers the basics of clutching real well.

[IZZ]

Thanks Turk, Ive seen his clutching book before and was curious if it would be helpful.

Now do I have to get a clutch puller to swap weights? or is there a way to do this without pulling the clutch?

Also I wont be able to give an accurate report on what the rpm's are doing while riding it till this weekend (hopefully).

Tony, something else Im curious about is that setup you list for a PSI piped 800 with hauck orange -17.2 rivets - 52/42 helix, I wonder if Id be closer to optimal bolt in clutching with that setup? whats your opinion on that? The rpm's might be a little high for my pipes right? but other than that Im wondering if shifting and engagement might be better suited than this Blue - stock rivets - 49/43, that Ive got in. I could always work on bringing the rpm's down a bit. But I have noticed that in the past youve said that setup wasnt as trailable. Just curious how so?

Thanks guys!

[Reimond]

You can take clutch cover off to change weights (6 screws), but it's more easy to buy pulller and take the clutch on table.

[YAMMIEGOD 3:16]

DUDE, YOU ARE RIGHT!!! CAN.T RUN THAT SET-UP BECAUSE THAT IS FOR 800 BLASTERS THAT PEAK AT 86-8800. I DON,T WANT YA TO OVER REV EVEN ALITTLE. YA NEED TO BE AT 8350. ALSO, YOU DON,T NEED TO PULL CLUTCH TO CHANGE WEIGHTS. TAKE MAIN BOLT OUT, GET A 10mm SOCKET AND REMOVE SIX SMALL BOLTS. COVERS COMES OFF AND EVERYTHING CAN BE CHANGED. 3:16 (tony)

[JERSEYJOE]

Tony: I replaced the blue spring with the WWW spring ( stock weights), and I am running the 49/43 Dalton with the green spring at 6 /1. My question is that I think it is still turning a bit more than 8350. How accurate are the stock tachs? I know the road that I was on was slippery and I did not have a good hook up, but at full throttle it seemed like it was revving closer to 8800. I guess my real question is should I wait for a good packed trail to judge peak RPM. Engagement is right at 4500 with one shim.

Jersey

[YAMMIEGOD 3:16]

JOE, YOUR ENGAGEMENT IS RIGHT ON PERFECT. NOW YOU CAN WAIT FOR BETTER CONDITIONS IF YA LIKE OR ANOTHER THING YOU CAN DO IS PULL SECONDARY OFF AT RUN IT AT 3-3 @ 60 TWIST. STOCK TACHS ARE VERY ACCURATE. GOT BE NO HIGHER THAN 8350 WITH STOCK TWINS!!!! 3:16 (tony)

[IZZ]

Yammiegod, Finally got a chance to run my machine - engages a little over 4000 grand about 4200 - WOT it pulls like demon up to about 8300 or so and holds at that RPM for maybe 5-10 seconds and then - it feels like it upshifts or something, like in a car if you went from 2nd to 5th skipping all the gears in between - because the RPMs fall down to 6500 - 7000 and its all done pulling. Kinda just falls on its face. By the time it does this Im outta room so I slow down and turn and get back on it and its like its downshifted or something cause theres the power again stretching my shoulder joints outta socket.

So tell me, is this right? Is it supposed to shift once it hits 8300? or are snowmobiles supposed to hold rpms? Im completly ignorant here. Its awesome till it shifts up like that. I wonder if thats what the helix does? Maybe the springs not set right or something? I dont know can you kinda explain how thats supposed to work?

[YAMMIEGOD 3:16]

DUDE, 8350 IS PEAK. ANOTHER WORDS YOU DON,T WANT RPM TO CHANGE UNTIL YOUR OFF THROTTLE. NOW, WHERE DO YOU HAVE YOUR SECONDARY SET AT. ALSO WHAT HELIX. YOU RUNNING MY CLUTCH SET-UP. 3:16 (tony)

[IZZ]

Tony, Ive got a helix on there I ordered from hauck its stamped with the letter "E" now its supposed to be a 49/43 thats what I ordered. I also got a blue spring from them that I put in the primary. Ive got a silver code yamaha secondary spring in the secondary and the ends of the spring are both in the #3 holes on the sheeve and the helix.

Now maybe its possible I put the helix on wrong or something? I was kinda confused on if I was supposed to wind it up or not when I put it on. I simply put the spring ends in the #3 holes and turned it to =where the bolt holes would line up. I also had the whole secondary off and apart so I could clean it real well. Im sure Ive got that back on right theres not much to it as far as I could tell.
Im goin out to measure things according to my manual (belt width and height in clutches and anything else I can look into)

Any ideas?

[YAMMIEGOD 3:16]

TRY 70 DEGREE TWIST. GO TO HOLE 6 ON CAM OR HELIX. THAT IS HOLE THAT IS UNDER 3 LOCATION. SOME GET 9 CONFUSED ON CAM WHICH IS UNDER 0. NOW PUT YOUR SPRING IN # 1 LOCATION ON SHEAVE. THAN WIND CLOCKWISE UNTIL STUDS LINE UP. DROP ON AND TIGHT,EN UP. 6 ON CAM = 1 ON SHEAVE EQUAL 70 DEGREE TWIST, THAT SIMPLE. THIS MIGHT HELP YOUR PEAK RPM STAY WHERE IT SHOULD BE. ! 3:16 (tony)

[IZZ]

Ok Tony, I was working on it and found a motor problem! maybe this had something to do with my problem, I dont know, check out the pics in "Pistons are melted" to see what Im talking about!

[IZZ]

Yammiegod, Could timing have something to do with why my sled acting that way (dropping RPMs) cause a guy told me that if my timing was nt retarding it wouldve ate my pistons up the way they were on the intake side!