Shimming Comet Driven Clutch Spring

[sharse36]

On my 1987 ezgo Marathon, I'm looking at shimming my Driven clutch spring. My cart up shifts to fast and bogs down. Has a new comet drive clutch and belt. I have a Comet Driven clutch that is about 15 years old. I believe the spring is getting weak. It is really bad on hills until you stop then you can make it.

How big of shim can put in it 1/4", 1/2", or 3/4" ? I have a friend that can cut the shim out for me with a laser so I can make it to the right size and thickness.

Any ideas how big to go to make it better with out buying a new spring or clutch.

[racin161]

Ive seen on this site 3/8 is ideal but they have also shimmed the drive clutch with a 1/4 inch. May give that a starting point and play with it. Good luck

[pachanga90]

If you are running bigger tires,Start with shimming the drive-clutch about 1/4"(I use 1-1/8" grade-8 U-Bolt washers,they fit perfect).The Drive-Clutch shim is very noticable with big tires,Nite/Day difference!Tear down the driven,If it has a shim between the sheaves,remove it.Then shim it 3/16"-1/4" to start.Try it and you can adjust from there.Hope this helps.

[sharse36]

I got the driven clutch apart today, 3 jaw puller worked great. Got the measurements to my friend to make the shim's. He going to make different thickness so I can see what works the best.

I also got the comet duster drive clutch apart tonight and got measurement for shimming that clutch also. Should have the shim's monday can what to see if it makes a diffrence.

[sharse36]

Tried to shim the drive clutch but did not work. No matter what size shimm I put in the clutch would not close all the way. might look at getting a stiffer spring for it.

I got the driven clutch shimmed at 3/8" and it made a big differences. Has good take off power and does not shift into high right away like it did. I try it going up a good size hill that always had to stop half way up and then start again to make it up. now it when right up no problem at all.

[pachanga90]

If the drive won't close all the way,I would look at the shaft the sheave slides on and see if something is damaged.The shim doesn't change the distance that the clutch moves,It only changes engagement rpm and slows the closing-speed of the sheaves,which causes it to up-shift slower,increasing torque (low-end power).With the 22" tires I had a Drive clutch shimmed 3/16".It worked great.I swapped out the clutch last year when mine went south.I forgot about the shim,put the clutch on and it was a slug.I added the shim and it was a Nite/Day difference.If your spring is shot,then this may be why you did not notice a difference.Try to find another spring and give it another try.We had ours in the woods tonite(with 3/8" shim in the drive),My wife came up to a dropped tree about 8" in diameter and 6" off the ground,It drove over it like it wasn't there,I almost S*** myself,I couldn't believe that it went over so easy!