Rebuilt my kids LT80 front and rear clutches. Modified the rear shoes by ligtening them to what was suggested on this forum and reduced the rollers in the front clutch to 3. Bought all new front clutch driven housing as the old one was trashed. Machine ran fine for a few months, now in idle you can feel the clutch "grabbing" and learching the atv forward along with some noise in the clutch area. Did one of the rollers fall out of position while in use or what could be causing this. My son didnt run it long when he noticed this so we parked it and I am about to dive in. Just wanted some hints on what I might find or did I do something wrong on assembly?

 

The clutches shouldn't be grabbing, especially if they were lightened, unless the one of the springs isn't hooked up correctly. I'd check those. The front rollers have nothing to do with it. They only adjust the gearing once it's moving.

Along with the springs in the rear clutch assembly, there is one other thing I can think of that would cause this. There are a couple little bearings in that assembly. They have to spin when the maching is idling and not moving. If one of both of those is starting to go out, that would also cause the maching to want to move forward when idling, at least a little. They would have to be out pretty bad for it to be noticeable though.

Why did you remove 3 of the rollers? Is it a heavily moddified motor? On a stock motor, most recommend removing just 2 rollers. The motor will have to turn pretty fast with just 3 and lighter clutch shoes. I'm not sure if a stock motor will turn fast enough to utilize the full bandwith of the variator gearing with just 3 rollers and lighter clutches. How much did you reduce the weight of each clutch shoe to?

 

A roller problem. Chances are a roller flipped when you assembled it.
Guess we'll see.
I agree, should be at least 4 rollers.

 

My mistake I left out 2 rollers when rebuilding leaving 4 (not the 3 as I stated above). I will look at both ends of the clutch. My thought though with the roller is that it ran fine for some time (days and hours), then all of a sudden the clutch problem started. If I had assembled it and the roller fell out, I would have assumed this problem would have been there from the first fire up but it was not.

 

Finally got to looking at my problem after some time. I took the clutch cover off and ran it with me on it. Under load I noticed the noise was coming only when the rear clutch started to engage on occasion. When this happens the atv doesn't move and makes a horrendous sound. Took the rear clutch drum off and shoes look fine the springs seem to be in place. The atv has a chain guard over the drive chain so I took this off. The chain has so much slop in it and the drive sprocket is worn to where the teeth are like spikes. I could almost take the chain off by hand. I think the chain being worn is seeing the full torque of the fresh engine and new clutches that it's slipping a tooth every now and then as evident from the metal dust in this area of the atv. I will have to post a picture but does this sound logical? I'm going to buy a sprocket and chain set I believe unless someone tells me I'm off in my thinking.

 

I think you're correct.

 

Here are some pictures of the drive sprocket, chain and drivene sprocket. The drive sprocket has 12 teeth, the driven has 26 for a ratio of 2.16? What should a guy do for this. I built the clutches for torque, should I change the gearing as well for torque? If yes then what ratio?

 

What you have is 1987/88 gearing with 428 pitch.
In 1989 Suzuki went to 520 pitch chain because it was "less loose". The sprocket sizes are : 11 front and 22 rear.
I'd stay with stock gearing as it has all the low end you'll need (IMO). Whether it's the 428 or 520 chain/sprockets.
A chain tensioner is a good idea especially with the 428. IMO, if you are going to get a tensioner, stay with the 428 pitch. Altho, 520 with a good o-ring chain don't really need a tensioner.
I buy my stock sprockets from Suzuki. Steel and relatively cheap.