JCL MP250A Runs Poorly 0-40 MPH & No Front Brakes By bob123456789 (Read 3,978 times)

[tvnacman]

I'm thinking to open up the clutch and variator to check. when you have things apart run the engine and rev it a bit see if the noise is there. I wonder if it is crank bearing noise.

John

[bob123456789]

Thanks for helping with this John.

One of the cooling fins on the variator is broken off. Could that make this noise?

I am charging the battery. I plan to removed the belt and run it that way to try to isolate the noise a bit more, clutch versus variator.

[bob123456789]

Just wanted to update everyone who has been helping with this. I had replaced the fuel filter and one side broke off. I have ordered a new one.

Once that is fixed and it is running I plan to take a video of the main shaft with the CVT removed to try to isolate if the noise is from the shaft, variator or clutch and upload it here.

[bob123456789]

Okay. We have hit a temporary cooler spell. It sure would be nice to get this thing moved along as much as possible before it changes.

The fuel filter is on. I pulled the belt and variator and ran it to try to isolate the noise to see if it was coming from the clutch or the front end of the CVT (main bearing, variator...).

Here is the video:

View My Video

Does the lack of any noise in this video mean that my main bearing is good? Boy, I sure hope so.

Please contrast the CVT noise in this video with the video in post 37 of this thread.

What is left that could be causing this noise? The clutch? How do we find it?

[bob123456789]

I'd appreciate input from all of the experts on here on how to solve this.

The video in post 37 contains my CVT noise which we are trying to solve. The video in post 63 shows everything with the belt and CVT removed. Only the main bearings.

In this video I have put the variator back on the main shaft:

View My Video

To me it looks like we may have isolated the noise to the variator

What is the noise coming from the variator? Should I be concerned about it? If so, how do I solve it?

I've mentioned earlier that my variator has one fin broken off. Here is a picture of it. Could this be the noise?



Thanks again for everyone's help.

[thecableguy]

Well, since the noise isn't there with the variator off and is with it (and only it) on, it does point us in that direction. Just knocking a fin off shouldn't cause a noise like that. Can you post photos of the inside of the variator? Rollers, ramps, etc?

Jim

[bob123456789]

This is my first time taking one of these apart. Don't ask me to do something dumb because I won't know any better.

Here are pic's of the inside of the variator.

[thecableguy]

Now pull the ramp plate off (the black piece in the top pic). You should find the rollers under there. Lets take a look...

[bob123456789]

Here it is:

[thecableguy]

ok, those rollers are all out of place. Clean all the grease out of there, clean the rollers and all the other pieces. Inspect the rollers, they should be round without flat spots.

When you put it back together, it should be clean and without grease. The rollers should be sitting in their ramps, in that pic, only 4 are in correctly. The ones we can see into are flipped out of their ramps.

Like this

Put it all back together, making sure to hold the backing ramp plate the whole time so they hold the rollers in place until you get the nut on.

I hope this all makes sense. I'm sure this is the root of your performance issues AND clanking sound.

Jim

[bob123456789]

I am so glad to finally find the problem! Thanks for your help Jim!

In general the old rollers don't have flat spots. I can maybe see two slight ones.

One of the rollers has a small tear in the plastic on one side in two places. Do you think I should replace it? Here is a picture of it:





Do you have any idea what caused the rollers to do this?

[thecableguy]

Rollers are cheap, I think you'd be OK cleaning it and slapping it back together with the rollers you have, but I'd order some new ones soon.

Weigh them with as accurate a scale as you can find to figure out the weight of the new ones. Either weigh them individually if you have a scale that'll read gram weights or weigh them all and divide by 8.

As you can see, when the variator is apart, the rollers can come out of their ramps pretty easily. What probably happened is that the variator was removed or the belt replaced without checking the position of the rollers and making sure to keep the assembly squeezed tight together while replacing it.

To put it another way:
The belt pushes against the variator face and the variator rollers are held in place between the backing plate and the variator. As the crank spins faster, the weights move outward, squeezing the belt and causing it to ride higher, changing the effective "gear" ratio.

If the belt snaps or the nut is removed, there is no force pressing against the variator face and the rollers can tumble all over the place. It's vitally important to be sure to keep this all together and the rollers in their ramps as you reassemble. Any time you change a belt or remove the variator you need to recheck the rollers.

Also, the variator does not need grease. The plastic that the rollers are coated in is self-lubricating.

Jim

[bob123456789]

What's the best way to put it all back together while making sure that the rollers stay in the right place?

[thecableguy]

Lay the variator flat, load the rollers in the ramps, slide the backing plate on and reattach the cover plate. (I've never had a scoot with a cover plate like that, but it should all work the same). Then just hold it together as you slide it on to the shaft. Once it's pushed back fully on the shaft, the rollers should stay in place as you fit the belt, fan and nut back on.

Watch this video.

Good luck, let us know how it goes!

Jim

[bob123456789]

Just wanted to update everyone. First I wanted to say a great big thank you to Jim for helping me find and solve the issue.

I got everything back together fairly quickly. A quick test on the stand and it appeared things were working on the center stand. I had to wait for the rain to clear up before I could take it for a spin around the neighborhood to give it the first test ride.

I just finished that test ride. I couldn't get it to accelerate on its own. It would bog down and didn't have any power.

One of the things I had messed with was the A/F screw on the bottom of the carb and the adjusting was never really finished. That screw is brutal to get to.

Where do I go from here? Are the performance issues related to the CVT or the A/F mixture screw? Could I not have the rollers back in correctly?

Jim I trimmed the one roller. The old rollers were 14 grams each. Luckily none were permanently damaged and I was able to reuse them. I put it together with no grease.

I'd really like to have fun riding it.