Over rev question,out of alignment?

Powderat · Nov 30, 2008

My buddys 01' 700MM is over reving. Motor stock except single layer headgasket and Bender can. It also has reverse and been stretched to 151. This thing revs over 9000 consistantly. We have pulled The primary cleaned and replaced the spring and added 4.5 to the outter hole.(already had 4.5 in the inner hole). Pulled secondary, cleaned and replaced spring and buttons. I'm sorry I can't remember whar gears are in it right now and we did try gearing it up one tooth. But he did add the reverse himself and I am wondering on the gearing. Two questions, What gears should he be running? Can over reving be caused by an out of aligned motor? Thanks

Linc · Nov 30, 2008

What's the secondary set at, 6-1 is a good start. The other thing is to check the rollers, if they are worn ( bushings ) the clutch doesn't shift right and can over rev. Take a small magnet and attach it to the rollers and see if they move up and down, if they move ,it's worn out, replace rollers, check ramps for wear. Likely the bushings in the sliding sheave and outer cap are worn, replace those and have the spider shimmed.

Powderat · Nov 30, 2008

When it was off the sled he took it in to the dealer to have the heavier weights installed and they said the sliders etc. looked fine. With the primary off how much movement(wiggle) should there be between the two sheaves? what proper measurement procedure is taken here? This is a new problem to me and I just trying to figure it out.Thanks

Linc · Nov 30, 2008

I don't know what the measure is, but check the rollers, most people overlook this, if the rollers have too much play then chances are the main sliding bushings are done, generally after 2000 kms 1600 miles the bushings start to go.

snowdad4 · Nov 30, 2008

if memory serves correctly, offset with reverse is 20mm, vs 15mm, without. gearing should be 21/40, with the stock 8t drivers

M.M. 700 · Nov 30, 2008

what elevation?

Did you try a new belt?

Powderat · Nov 30, 2008

Elevation is 500-2000', Yes on the belt. But, Snowdad4 you mentioning the different specs between having reverse and not brought to my attention that I bet when he added the reverse himself he didn't know to change the offset. Would that possibly cause the over rev??

Linc · Nov 30, 2008

Reverse has nothing to do with offset, the engine and clutches don't care about reverse, they spin the same direction regardless.

M.M. 700 · Dec 1, 2008

Linc said:
What's the secondary set at, 6-1 is a good start. .

Good question, What is the secondary set at?

Powderat · Dec 1, 2008

tried 70 & 80. If reverse doesn't care about center to center, then why is the adjustment different(5mm) between the two? The reason I'm wondering about the clutch adjustments is because thats about the only thing we haven't checked or replaced. tools on order.... Thanks

snowdad4 · Dec 1, 2008

just looked at the reverse install manual. no mention of altering clutch offsets. however, in some of the specs, some of the sleds with standard reverse have 15mm offset, some are 20mm. is the overrev occuring with the sled on the ground or in the air?

Powderat · Dec 1, 2008

Can the clutches being off either c to c or the offset cause a sled to over rev?

Linc · Dec 1, 2008

Not that much.Have you checked the rollers and sheave bushings for wear and binding.Do you have the stock spring and weights in it?

Powderat · Dec 1, 2008

He had the primary off the sled, took it in to our dealer to have it checked out and the heavier weights installed. Acording to them the primary was fine. He's pulling the chain case cover to verify gearing. What gears would you run on a 700M w/151 and reverse? Thanks

Linc · Dec 2, 2008

Check the primary yourself the way I described above, if the dealer doesn't know how, then you're relying on his inexperience.

21- 40 I believe is stock, with reverse you don't have any options for lower gear on the bottom gear, and one tooth difference on the top will lower it alot but you can try it, it's a cheap try.

snowfishman · Dec 2, 2008

Linc,

Running 39/23 gears on 2000 MM with reverse, 8 tooth, 151 track, can this cause the over revving? Stock should be 40/21, reverse kit came with the 39/23. Will adding the smaller 21 gear to the 39 increase or decrease revving?

Linc · Dec 2, 2008

If the clutching is in the ball park, it shouldn't effect the revs hardly at all, over reving is caused by a binding, too light of weights, too stiff primary spring, too stiff secondary, slipping from being too loose. if there is black marks on your clutch it's slipping, if it's smok'n hot, it's slipping. Take a black marker and put stripe on the face of the primary go for ride and seee how far the belt goes, if it goes near the top and it's over reving then you will need more weight, if it only goes half way, then the springs are too tight or it's binding.

snowfishman · Dec 2, 2008

over revving

Thanks for getting back, I will check clutching again. However, what gears do you think would perform best on the 151 track, 21/39 or 23/39

Linc · Dec 2, 2008

21/39, but if you can get a 20 /39, that would even be better, generally a 2:1 gear ratio is a good basis point to start from, 21/39 is 1.83:1 and 20/39 is 1.95:1.

Over rev question,out of alignment?

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