CVT Components?

[Doug10]

Well i finally braved pulling the cover off to see what is in this thing. The previous guy raced TT with it and i was not sure of his setup. I really cant tell much because its all new to me, but there is a big old candy apple red spring behind that smurf blue clutch bell. Belt is still wider than .628". I cannot get either of the nuts off, must need to have a cordless impact so ill go that route tomorrow. Here is what the bike does now.....

Hauls butt....but from a standstill with rider and without (hes only 40ish lbs) the bikes clutch engages really early, not much throttle at all and pulls but if you floor it or half throttle it,it pulls and takes off but its a luggy pul, then it takes about 10-12ft before she really screams. If you have it going on the track and revved and hit it theres no problems but for having a 18/35 gear setup, im a little disappointed. Which direction should we go with this?

I tell you how early the clutch starts to lock up is when its on the ground at a moderate to hi idle it is trying to lurch foward.

Here are some pics of what I could see tonite, dunno if you trained pros can identify that this would be stock Polaris Scrambler hardware or possibly aftermarket.

Doug

[Doug10]

2nd one

[Doug10]

Heres the last one, i did notice a used set of variator components in my junk box that came with the atv. That variator on the atv now just dont look the same as the one in the box.

What are you folks suggestions on a good MX setup, and we also do the sand drags sometimes.

[mmsoup]

Good Pics

Looks like you still have electric start components in there on the front variator.

Couple of observations

1. Belt is not a stock 787 16 30 (Depending on brand and displacement)

2. you don't appear to have full travel on the front variator based on
visible wear

3. The belt is sitting low in the rear pulley which would suggest weak spring or short belt

I would replace the torque spring before I did anything else. will probably go a long way to solving your stall issues. Go get a tiny tach if you really want to know and determine what the stall speed is (RPM motor is turning when clutch engages)

Do you know what weight rollers were being run?
What displacement is motor?

Impact wrench to get nuts off, then seperate clutch from rear pulley (carefully) and remove torque spring and post picture for identification if necessary

[Doug10]

Will do, on gettin it apart.

I can tell you what i know....

It is a scrambler 50 (is true 50cc)
Has hi comp malossi head, has stock cyl. that has been ported, has drr50 pipe, i think it has aftermarket ignition, no rev limiter. I will get the tach on and check it out but you cant rev it up at all without it starting to pull. I was pulling on the belt a little bit tonite, but when the pictures were taken the atv was rolled around prior till. I know my jetting is pretty close for the stock 16mm carb.

Will check the other stuff and let you know. Ill take some pictures when i pull it apart of belt wear on the pulleys.

Doug

[nastynotchback1]

I too would replace the torque spring first but i would also replace the shoe springs.Put you tach on it and i bet your not even getting to 5000rpms before it tries to engage and thats gonna be too low.

[jerkyboy]

From looking at the picks. The belt isnt sitting all the way down in the front variator cousing that lag on takeoff. Like said above new toruqe spring should help this. Might need to shim out the front variator to get the belt down. If your not running TT with this Id put a 780 stock drr belt on it.

[Doug10]

Okey i took some good pictures tonite. In some of these pictures you will notice a new set of variator pulleys compared to the ones there were on here. I had them in a box that came with the bike. I think that one maybe for the scrambler 90 and one the 50 because they both are a little difference in regards to shape and bushing dia.. I did note that the outer half on the bike when i pulled it downs center hole was bigger than the splined shaft, thus relying solely on the star washer to align it up. The one I had in the junk box's center dia. was smaller and the splines fit it like a glove. I think maybe someone put half of 50 and half of 90 on there somehow but it managed to work due to the star washer centering it up. I did note that on the polaris diagrams the 50 has the bushing in the center and a washer to space it apart a little more and the 90 only has a bushing. There was no shim in this one other than the bushing when i took it apart. I also know that the clutch is not stock because the nut that is supposed to hold the clutch together is integrel on this clutch and is seperate on a stock one. The weights are 6.5g each.

First picture is the wear patterns.

[Doug10]

2nd picture shows the inside of clutch bell.

[Doug10]

This picture shows the red colored spring in the clutch. Not sure what kind it is but sure is a metallic candy apple color. Cant get the clutch apart due to not having the right size socket tonite. Also the springs really have no color other than a gold tint inside the clutch for the shoes.

[Doug10]

This picture shows the difference in the hole sizes on the outside pully halves i was talking about. Im thinking about putting the smaller one on because it just makes sense.

[Doug10]

Last picture shows the difference in the inner halfs for the front. Im thinking that the bushings between the 90 and 50 are different too because they too are different part numbers. If thats the case then the different size dia. of bushings makes sense.

[mmsoup]

Looks like a Yamasida Clutch or stock possibly lightened. The front variator that was in the box looks like it had good travel when it ran. The drive plate that was on the front variator is just worn

The whole package is wierd to me due to the paint.

Spring is wierd, blue paint is wierd diamond pattern in bell is cool though.

Clutch springs look stock.

Cheapest fixes

Replace the clutch shoe springs with either orange (Medium) or red (Hard) springs

Replace the clutch torque spring with a KOSO 1500 or Max RPM1500 spring (You can loosen nut with a large crescent)

get some 5 gm weights to start and have some 4 gm and 6 gm rollers to throw in. You can mx them up to get different weights

You can place shims in the front variator to allow the belt to start lower if it isn't resting against the bushing to start

See what happens and let us know

[Doug10]

Whats a good fix to ensure its right and no mixed back of junk. Local guy was telling me 5g weights with a white spring in the back but everything i have read says red.

Id like to get a good reliable setup put in and not just band aid this one up because the clutch shoes are wearing good and whatnot.

[Doug10]

Well lesson learned, the threads on the brass nut on the bell are soft, stripped em off this morning with impact putting it back together., I did find a shim for the variator that i put in to try and see what happens.

Doug

[Doug10]

Well i found a nut and put one on there just to check our numbers out. Clutch starts to pull a little bit at 3,000 but really kicks in where i cant hold the tires back with my leg at 3500. Definitely better than before just by adding 1 shim to the variator.

Max RPMS on the stand is 10,800. Its a little smokey to be 50:1 but the rings are most likely worn or else i need to go to a 100 main on the 16mm carb or pull the needle back up a little bit. Definitely a little better though. It will turn the tires over now in the garage floor. I think im getting there.

[nordic quad]

That looks like a Metrakit spring,i got one of those with a variatorkit i bought for a 70 a while back,if memory serves me right it engaged early and did not last very long.
Stein A

[mmsoup]

Just looked back and realized that you were running a 50.

Also confident that you need to work on the stall speed based on your reported 3500 engagement speed

Try to get the engagement above 5K I run both of my kids 90's at around 6500 RPM engagement

The roller weight, spring combo I mentioned earlier was a basic set up for a 90. I don't have the background on a 50 to be certain. I would ask for input from some of the 50 guys here on that. If I had to guess it would be a 1000 torque spring and 3.5 - 4 gm rollers with orange shoe springs.

[Doug10]

What is the tell tale sign that the variator pulley is spaced right? Is there a number I should be looking for with a micrometer between the pulleys or what? Maybe a feel thing? I know by addin the shim the belt went lower but is not all the way down yet. I know it goes all the way to the top at wot.

[Doug10]

So having all the free time that I do with a 2 and 4 yr old I tinkered some more tonite. After adding the only shim I had to the variator and increasing the stall a bit i drew a line on the pulled and cranked it over for a minute or 2 to see how far down the pulley I had reached. I am out of shims but should I go more?

[Doug10]

Also got the clutch apart and found alot of old grease in there. Whats the best lube to use on this for reassembly? Seemed to only be where the pins were but was still rather goupy. The spring is 3.975" uncompressed but has no markings on it nor does the clutch.

Doug

[Doug10]

And last but not least here is the pics of the wear marks on the rear pulley. I promise im done posting pictures now and throughout this whole ordeal I have learned a great bit about the cvt setup. Thanks guys.

Doug

[mmsoup]

I like my belt to be nestled down on the bushing in the front variator at rest

I like my belt to be all the way to the top of the rear pulley at rest

I use a Malossi overrange system on both of our quads and we generally see wear marks indicating that the belt has traveled to within 1/8" of the top of the front pulley.

Put your marker back on the inside of the front pulley in a straight line from the bushing to the outer edge of the front drive plate (Has the star washer) run the quad for a few laps hard and take it apart and determine how much belt travel you are getting. The wear marks I'm seeing on your front variator look like you aren't getting full travel and your belt was sitting way too low in the rear pulley.

[Doug10]

I am getting full travel to the top of the front variator on the stand when i run it. Looks like maybe another shim would put me near the bottom at idle or possibly putting the 780 16.5 belt on that im picking up tomorrow.

Doug