clutch question and glad to be a member

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alaskanbowtie

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I have a Mnt Max 700 I bought from a friend . I have noticed a slight vibration at idle and slow speed . I also noticed when idleing the drive clutch wobbles a very little bit then when a little throttle is applied it straightens up and spinns perfectly round it also squeels when first taking off and every time you stop and take off again (sounds like a cricket kind of ) . The clutch is a new comet . Is this normal or should it not be doing this ? The clutch is on tight I double checked . He rode it for about 300 miles last year after installing the clutch before moving and selling it to me . Also how can I tell what year it is ? I can't get a hold of him to ask and I gave his wife the money and she didn't know . THX all info apprecited !
 
The wobble is probably just idle shake which is perfectly normal. Check your secondary for belt height, ...that might the source of your squeel.

...and welcome aboard! :yam:
 
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could be the primary is out of balance or the crank runout is out of range. did your buddy have his stock primary blow up or did he ever have any left side impact?

i have not seen this kind of wobble when inspecting my primary. i banged up my sled on the primary side once and had to have the crank runout checked to make sure it was in range.

the belt squeel also tells me something is out of alignment, either the center to center distance or ride of belt in the secondary, all of which can be adjusted.

stock primary has been known to blow to pieces on some yami models.
 
impact from side

Yeah he did wreck the sled and a small piece of something penetrated the tub busting a piece out ot the middle of the primary . This is why he put the new clutch on it . He also had it snap the bolt off , holding the new clutch on after about 50 miles of riding . So he drilled it out then retapped it and put the new one on gently and it's had around 300 miles put on it since then with no problem . He did say that the primary wobble was much worse before it snapped the bolt and he thought he didn't have it on tight enough , hince the bolt breaking . I'll check the clutch alignment I have that tool but how do I check the ride hieght on the secondary . could you explain "crank run out and what this will hurt if anything being out . THX
 
Yeah he did wreck the sled and a small piece of something penetrated the tub busting a piece out ot the middle of the primary
Click to expand...

Sounds to me like like it was the other way around, the primary blew and punched out of the tub and caused him to wreck. Yamaha primary with the hard 8DN belt in the MtnMax are known to get too hot and eventually blow. Look at the Hartman Inc site for a description. I bought a 2000 MM that the previous owner had that happen as well and he sold it to me with a new Yamaha primary. After reading and seeing it first hand I looked at my 99 mm and the primary is starting to show evidence of cracks too. This will be my wifes/spare sled so it won't be ridden hard and I'll rebuild the primary next summer.
 
Check the ride height on the secondary, squeel is probably the belt a little tight there are three small bolts with shims on the back of the secondary. You may have to remove a shim. Try the Ultramax 3 belts, not so hard and will run with less slip and cool the clutches.
 
According to Hartman, the Ultimax3 belt is also 1/4 longer than the stock 8DN belt thus allowing it to ride a little higher in the secondary.
 
belt

I will buy an Ultimax belt and put it on also check the ride height , a friend of mine can help me do this . as to "WRDAL" he actually did wreck , missed a corner at about 80 and hit some small alders . broke a trailing arm and bent one of the Olin shocks etc. this is why he replaced the clutch with the comet . Now are the Comets any good ? should I consider running a polaris clutch or something else ?
I have a friend who runs Polarsi primary on his Yamaha , and he says its a much better clutch been doing it for years . Can someone tell me what weights and springs I should have in this comet . I'm in the process of doing these mods the air box , SLP can , a set of vforce reeds/spacers and 1 layer from Head gasket gon . THX I'm fairly new to modifying sleds and this sight is GREAT ! Any other suggestions I should do would be great too . I read something about notching the reeds ?? Can I do this with Vforce reeds & how do I do this ? I'm quite green so all help appreciated ! :rockon:
 
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There is a fella called Hammer on this site or Info site and he seems to have a wealth of knowlege on polaris clutches on Yamaha. He also has a pretty extensive post on the Snowwest forum.
 
if its a non power valve motor yes youcan do the reed notch. the instructions for it are in the tec section.
 
Crank run-out is measured with a dial indicator. With the clutch off, place the tip of the dial indicator on the crank shaft taper about halfway out. With the spark plugs out slowly rotate the crank shaft with the pull rope. Maximum runout is usually .0012" to .0020". If it took a pretty hard hit, it can knock the crank out of true.
 
Bowtie,

It's generally thought that VForce reeds aren't worth the money on a yamaha. The stock reeds are actually pretty good, if you want to spend the money, just buy a set of carbon fiber reeds for about half the price of the VForce's.

Do either the reed spacers OR the reed stopper notch, not both, they address the same thing (a blocked transfer port).

I've heard that the airbox mod is really for higher altitude (8000 +), not our AK altitudes. If you do the airbox mod here, it makes jetting finicky.
 
great , this was the exact info I needed

so I shouldn't do the spacers if I do the notch . Which is better or is there a better choice ? Also I want to set the sled up for all around riding , from 500 ft. above sea level to 4,000 ft. If I cut the can apart and gut it myself will this be the same effect as an SLP or sno stuff can ? I plan on doing single layer head gasket , carbon fiber reeds & spacers (as you suggested) , 142.5 jets x 3 and a Can or gutting mine . I thought that even with the airbox mod at low levels it would allow more air in which helps with breathing and in turn runs snappier and over all better . Perhaps I'm wrong . I understand that it will naturally run rich at the higher altitude but I only ride there every once and a while and the change is more work than benefit . The other question is whats the best secondary clutch mod to do for most benefit verses cost ? It has a Comet clutch with the comet suggested weights & spring for the primary . Can someone suggest weights & better spring for the primary also ? I'm asking alot of questions but I really would like the help so I don't have to do this but once . THX everyone
 
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You don't mention which side of the clutch appears to wobble. Vibration from an excessive amount of out-of true on the crankshaft will only increase in intensity as you increase RPM. What may be a problem are worn or damaged bushings on the movable sheave. Once the weights push harder and equally on the rollers the sheave should true itself and stop the wobble and vibration. When the bushings wear the sheave can't apply pressure square to the belt and essentially cause whats called an angular misalignment with one sheave not parallel with the other, this will also cause binding and a weaker engagement and belt squeal. Something to consider anyway. Good luck.
 
I will look into this

The whole clutch wobles slightly at idle and then when you apply a slight bit of throttle it spins perfectly round . Squeeks after it's been riden for about 5 minutes and you stop , only when it's idleing it squeels (kind of chirps) then when you go to take off it stops . I will be getting the time this week to start doing some things to it and pull it in my buddies shop to look at the clutches etc. The primary (Comet 108 EXP.) only has about 300 miles max , but your description sounds most accurate so far .
 
My sled makes the same noise

I have just finnished alighning the clutches with a sled pro alignment tool (they were way off) I will post here after next weekend when I will ride next .

Hopefully the noise is gone
 
The choice of reed spacers or reed stopper notch is really a choice of spending money or spending time. The spacers will run anywhere from $25-60 depending on where you get them. If you can find a Western Power Sports (WPS) dealer, they have the spacers for about $25 (call GoPro in Anchortown). Outfits like Bender and MaxxPerf (or the dealer) sell the same thing for about $55-60. The notch you can do for free, just takes a little time. One side affect of the spacers is a small increase in the case volumn. I've read conflicting opinions on this, some say it's good, some say it's not good. Personally, I have one sled with spacers and one with the notch. Throttle response is similar on both.

Be careful with the 142.5 jetting at lower altitudes (below 300) and colder temps (below 0) check out this jetting chart look at the top row in particular. My 99 is jetted with 142.5s but it mainly gets used at Petersville (1300-1500 ft) and when it's warm (+5 up). I run 146.3s and a Tempaflow on my '00.

I'm looking for a good secondary setup too. I've read on the SnoWest forums that a 43 helix (stock on my 99 & 00), green spring wrapped to 70 or 80 is pretty good for all around performance on a MtnMax. I'd like to get more info on roller setups though.
 
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tuning

Great thx for this info I rarely ride below 300 ( from about 250 to 2,000 ans occasionally at 4,500 ft.) if it's colder than 5 degrees then I will probably not be riding either , so I think it will be ok . I will keep that in mind for sure ! Thank you so much ! I will look at the secondary spring this week . How do I tell if it's at 80% ? THX Mike ;)!
 
Mike,

If you look at the face of the secondary helix, you'll see the end of the spring sticking out of a hole. That hole will have a number next to it. The other end of the spring is in a hole on the fixed part of the secondary. That hole has a number next to it as well. Each of parts (helix and fixed sheave) have 3 holes. The fixed sheave has # 1, 2, 3 the helix has # 3, 6, 9 (or something like that and I might have the number locations reversed). You put the spring ends in different holes to get different preload. Add the numbers together and multiply by 10 to get your preload. Example: hole 6 and 3 gives 6 + 3 X 10 = 90 or 6 + 2 X 10 = 80.

In my earlier post I said wrap to 70 or 80, that should be 60 or 70. 80 will give better backshift, but might kill the upshift. Play with different settings to see what you like.
 
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clutch

Do yourself a big favor and can the Comet. Either go back to the yamaha clutch or the P-85. On the Yammy clutch use the factory set-up or call the guy's at MPI. For the P-85 call Tom at Hartman Inc. I run at higher elevations than you do to give a good set-up. I used to ride those areas. It has been about 11 years. Things have changed. I'd like to see what my sled would do at sea level. We ride at 10k and higher.
 
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