Any1 Blowing Belts

[Arctic Cat Dad]

We got the clutch tuned,got rid of the bog. It needed a 2000rpm spring. It was kicking into high gear way to early. It rips out of the hole now. We have blown 2 belts. The first 1 was a 787 it was to wide and blew on the 2nd lap.They like the 780 belt.

Now I believe were getting to much heat in the clutch area and this is my problem.Any1 blowing belts and if so what did they do to fix the problem.

Here are the mods. 09 90cc mxr:Hetrick Port and polish,28mm carb,Hetrick National pipe. Clutch: 5g rollers,2000rpm torque spring,780 belt with 1mm shim inside the variator.

I was thinking of removing the cover where the starter was and running a vent hose up under the seat and up by the Hetrick XC air box {which is up front under the nose above the Rad.}

This clutch Problem has killed us in the points in the Nats. He and another {8-11} 90mod rider left the rest of the pack and had checked OUT and in the top 8 overall on their 3 lap out of 65 riders.He atleast had a 2 place in class and top 5 overall. Then the belt blew. We have only had 2 good finishes out of 6 races.

This is an XC mini and we run 1hr, I can't remove the plastic cover.we need it to keep the mud and water out.

Any Thoughts?

[hotquads1]

a 1500 t-spring would be less stress to the belt , you can also get a 787 belt that is not as wide as the 780, just for ideas.
marc

[marsrace2]

we have run the 787x17 apex belt for over a year with no problems, you need to use 2 shims though inside the variator when using this belt.

[Arctic Cat Dad]

I was told today about the 787 with 2 shims. I think I'll try that. The boy weighs 114 lbs that is why we went to the 2000 spring. If you run the 780 with a 1500 toque spring it has a bog about 20 ft off the line. It comes off the line good then it kicks into a higher gear and the whole pack flys by him. Then he has to run the quad even harder to pass them to get up front.

I talked to the Apex tech man today and he told me about the 787 2 shim deal he said it will stay together.He was the 1 along with Rich who decided that the 2000 spring was needed because of the weight.

Thanks for the ideas guys.

[saintmick]

i went through this last year 3 belts in 0ne hour and a half race.
if you have a bike producing more than 14hp you will need the malossi overrange or an easy fix is to gear the bike down you may be suprised how well this works and use malossi belt 6112742 or polini belt 17t front 30t rear and it will still pull 45-50mph my sons bike was 16hp never had the problem again we tried every thing hope this helps
mike

[bulldogfallon]

Your bog could also due to the RPM of your clutch engagement...


The 787 belts we have seen are 16 wide...the common 17 wide belt is 788 long.


Your rollers set your shift speed...(where the pulleys shift and your motor locks rpms)--


Your final drive ratio can also create heat in your cvt.


The amount iof shims used would also very by the variator manufacturer....shims also very in thickness

The more you shim the front of your variator the more stall speed you will have if im thinking right every 1 mm is 500 rpms more. Just to let every one know. With the stock clutching IMO the 787 16 30 is the best belt for stock now the Malossi 617216 is the best for highly modded variator and clutch set ups and only if you know what your doing if not you will get frustraded. Just a little insight.

[ecmini1]

Man I read that title and it sounded X rated.

You got all the best advise already:D

[Arctic Cat Dad]

Blew another belt in tha first lap of the last national. He is so used to it he doesn't even get mad anymore. I give up on this mini. It's for sale right now. Here gonna build a raptor or a 300ex. The mini thing is over. He's not having any fun anymore they just aren't fast enough.

[dazed&confused]

i would try a ztr 1500 or a malossi 2000 ,you have some serious heat issues.

you have to really test with other springs and rollers and find out what the quad and rider like the best .then do 75 to 100 yard runs and time him, do this consectively so you can see if it falls off from heat in the clutchs.this will tell you alot .

i have found out that a koso or ztr 2000 spring is just to stiff and creats to much heat. jmo

when you get the clutchs rite then you can change your spockets to get your mph faster.

good luck !!! hate to see you give up already. lol

[QuadJunkies]

Originally posted by Arctic Cat Dad
I was told today about the 787 with 2 shims. I think I'll try that. The boy weighs 114 lbs that is why we went to the 2000 spring. If you run the 780 with a 1500 toque spring it has a bog about 20 ft off the line. It comes off the line good then it kicks into a higher gear and the whole pack flys by him. Then he has to run the quad even harder to pass them to get up front.

I talked to the Apex tech man today and he told me about the 787 2 shim deal he said it will stay together.He was the 1 along with Rich who decided that the 2000 spring was needed because of the weight.

Thanks for the ideas guys.

We have went to making our own shims, how much spacing on the shims are you doing ? Ours might be just a smidge too much but seems to be working. We too use the 787 and 2000 spring since Brandon has broke the 100 lbs. mark this year.

[QuadJunkies]

Originally posted by dazed&confused
i would try a ztr 1500 or a malossi 2000 ,you have some serious heat issues.

you have to really test with other springs and rollers and find out what the quad and rider like the best .then do 75 to 100 yard runs and time him, do this consectively so you can see if it falls off from heat in the clutchs.this will tell you alot .

i have found out that a koso or ztr 2000 spring is just to stiff and creats to much heat. jmo

when you get the clutchs rite then you can change your spockets to get your mph faster.

good luck !!! hate to see you give up already. lol

How big is your rider?I think alot has to do with the rider. How good does the quad launch? Another thing to consider is that center bushing in the variator seems to vary in width which changes your belt spacing.
Just this year alone we have been threw 6 bells and have literally tried every combo there is. These bigger kids have a tougher time . Most of the kids we see over here are much smaller than my son and the way we have him set up right now hes usually still right up there at the front for holeshots.

[QuadJunkies]

Originally posted by Arctic Cat Dad
We got the clutch tuned,got rid of the bog. It needed a 2000rpm spring. It was kicking into high gear way to early. It rips out of the hole now. We have blown 2 belts. The first 1 was a 787 it was to wide and blew on the 2nd lap.They like the 780 belt.

Now I believe were getting to much heat in the clutch area and this is my problem.Any1 blowing belts and if so what did they do to fix the problem.

Here are the mods. 09 90cc mxr:Hetrick Port and polish,28mm carb,Hetrick National pipe. Clutch: 5g rollers,2000rpm torque spring,780 belt with 1mm shim inside the variator.

I was thinking of removing the cover where the starter was and running a vent hose up under the seat and up by the Hetrick XC air box {which is up front under the nose above the Rad.}

This clutch Problem has killed us in the points in the Nats. He and another {8-11} 90mod rider left the rest of the pack and had checked OUT and in the top 8 overall on their 3 lap out of 65 riders.He atleast had a 2 place in class and top 5 overall. Then the belt blew. We have only had 2 good finishes out of 6 races.

This is an XC mini and we run 1hr, I can't remove the plastic cover.we need it to keep the mud and water out.

Any Thoughts?

First thing you need to do is measure the spacer in the front variator to see what measurement it is because it will change your shim spacing and your belt size. It took my Husband forever to figure this out because the center collar/spacer were dif. widths(not sure what correct terminology is on those things)

787 with 1.44 mm shim spacing with a 2000 main spring with 6 gram roller weights seems to be working well for us. We might reduce the shim spacing by a fraction .02 mm at some point trying to get a good luanch but good top speed.
Check your PMs.

[dazed&confused]

my rider is 108 lbs ,and we could not keep the clutchs from overheating.
we did so many test runs with a stop watch and radar gun and
found out that the molassi2000 was the best spring to keep the heat down ,since the change we have not lost any belts.

once we got what the quad liked in rollars and springs we messed with the sprockets and got the hole shot power with out losing our top speed.

this may not work for everyone but it worked for us.

[QuadJunkies]

Originally posted by dazed&confused

this may not work for everyone but it worked for us.

Exactly. Alot goes into how the motor is built too.