Jerky acceleration - clutch issue?

[NYCaver]

I just recently picked up a new to me Brister's 2 seater go kart.

I'm slowly working my way through a short list of issues to make this thing safe for my kids. Top on the list is what I assume is a clutch issue, but my DIY experience is with cars and motorcycles, not go karts.

Basically, at idle the clutch is a little grabby and unless I idle it real low it likes to take off, and when choked it idles higher and really wants to take off. Once riding the acceleration is very jerky. When hitting the gas it feels like nothing much is happening and then it takes off suddenly.

Sorry, I'm not really familiar with the right terminology, but I'm adding some pics for reference. Any help appreciated.

 

[Whitetrashrocker]

First off, denny will be proud that you have a comet branded belt.

It looks like the whole TC assembly need maintenance. Take it off, open the driver unit up, clean and dry lube. The sheaves (where the belt rides) should be almost polished.
Same with the driven unit.

There are a few videos out there showing how to do all that.

Those roll bars make me want to carnival ride that thing.

 

[Denny]

You have a 20 series CVT. WTR is correct about cleaning the clutches and replacing any worn parts and polishing and using graphite dry powder to lube. And finally thank you for being smart enough to use a Genuine Comet belt! You may want to see if you can get stronger springs for the primary clutch to delay engagement and replace the belt.

 

[NYCaver]

Thanks guys, awesome info.

Servicing the torque converter/clutch seems well within my abilities so I'll look up some videos on guides on that and see how it goes.

 

[JimD]

When you clean the unit you will notice the driven unit (7" pulley sheave) with say Max-Torque on the cam. If you would take one more picture with the driver unit floating sheave and cover removed. I want to see how the belt is sitting on the fixed sheave. The belt may be too loose and the picture will tell me. We quit making the belts in 2005 when fun kart production STOPPED. The belt you may want to order would be Comet's number 203581 which was the same as our MXT98L.

A loose belt will make it jerky as well as a dirty unit. All the hints given so far are excellent. If you want the driven unit cleaned and serviced all you have to do is pay for the shipping to and from Max-Torque. It will look like new when you get it back, good for a 10,000 miles.

 

[Denny]

Caver, JimD owns Max-Torque and is a hell of a good guy!

 

[NYCaver]

Thanks JimD! Excellent info and I can follow up with a picture of how the belt is sitting in the sheave. Not sure when I'll get around to it but I'll post it.

 

[NYCaver]

Ok, I got the driver unit apart today and took a look. Attaching pictures so you can see evaluate.

Definitely a good deal of corrosion on the sheaves and inside the sleave where the splined hub rides. I did my best to clean everything up with steel wool and sandpapered the guides where the hub needs to slides back and forth. Cleaned it all off with brake cleaner and then graphite lube for all the sliding surfaces. For sure it's not perfect and some of the more deeply entrenched corrosion I wasn't able to get rid of.

It definitely drove better and didn't want to take off so much but it still feels like the best grabs pretty sudden. What so you think? Is the belt shot?

 

[Denny]

They do engage kind of suddenly. Remember it is a Gokart and not a $50,000 car.

 

[Whitetrashrocker]

The sides of the belt do the work. Check to see if it's uniformly even width. It's is worn it will cause jumpyness

 

[panchothedog]

Put in stiffer garter springs, ( your picture #4 ) and it won't creep at idle. I don't think your belt is too short. The way it wraps around the driver looks right. It does look like it has a lot of time on it. When you order the new springs, get a new Comet belt to go along with it.

 

[JimD]

Yes, it needs a good cleaning but you definitely have the wrong belt on there and that is one of the reason it will jerk start because it cannot get any pressure on the side of the belt until you are near maximum rpm. What I try and shoot for when you put the belt around the fixed sheave of the driver unit is you have about three business cards clearance above the bushing.

Since you know you have the wrong belt I would cut it so you can fit the belt over the driver sheave and see how much belt you have past the cut. Give me how much excess belt goes past the end and then I will tell you which COMET belt to get.

Plus send me both the driver and driven and they will be reconditioned to give you many years of fun. The Brister kart you have is a very good back yard fun kart. The company that bought Manco also bought Brister. The bought Brister to get the Chuck Wagon, (an ATV) which was already in Rural King and Tractor Supply.