Intro/Yerf Dog 3203 Newbie

[Pittsjock]

Greetings:

Long time gearhead, new owner of a Yerf Dog 3203. I haven't owned a go-kart in about 30 years.

I bought this cart as a birthday gift for my 10 year old son which was today. He is a decent driver at this point and has pretty good dirt bike skills. We will tune it up over time, but for right now, I just want him to have safe fun with it.


We got a pretty nice 3203, but the jackshaft was broken at some point and a PO replaced it with a centrifugal clutch. In retrospect, I probably overpaid @ $550, but the "single mom" promised that they had been using it and had just recently broken a bolt on the carb yada yada. I noticed the jackshaft, but wasn't familiar enough with the design for it to mean much to me. I could have purchased a cherry one for $700 - probably should have.

I had a few teething problems with the motor, but got that straightened out today. Standard Tecumseh 6.5. Running OK - I think most of the problems relate to lack of use and will smooth out as we run the motor a bit more.

The clutch was pretty rusted so I soaked it with PB Blaster to get things freed up and moving. Once the residue burned out, I got a little motion, but it won't go uphill at all. Once the kart gets moving, it does OK.

1. Will this type clutch give decent service if I clean it up/replace it? We live on a farm so this will be mostly off-road use in cut grass and on dirt roads.

2. Do I need to find the parts to rebuild the jack shaft and go with a torque converter?

Thanks for your help!

Patrick

 

[OzFab]

IIRC, that particular kart came standard with a CVT (torque converter). I can't tell you why the jackshaft mount has a redneck lifter kit, what I can tell you is replacement jackshaft components can be bought relatively inexpensively, a whole replacement kit is less than $50, all you need is a shaft &, maybe, bearings.

Centrifugal clutches don't like hills, that's why karts of this type use CVTs

If it was me, I'd fork out the dollars to return it to it's former glory; I think you (& your boy) will be much happier with it...

 

[landuse]

I would also get a CVT and replace the centrifugal clutch you have on it. Your gear ratio is probably waaaay out of wack and that is why you can't make it up any sort of hills.

 

[Pittsjock]

Thanks for the replies gents.

I went ahead and ordered the parts to get the proper jackshaft/tc setup going again.

My son had a blast today, but I am too old to have to push him up the hill every time

Parts arrive early next week. Pics & update to follow.

Happy 4th!

 

[Pittsjock]

My parts arrived today - new shaft for the jackshaft and 30 CVT

I need key stock and I am guessing collars for the driven side/jack shaft?

I am guessing that there is no "thrust" bearing/washer/concept involved in the jackshaft because, as long as things are lined up correctly, there should be no side loads on the jack shaft?

I haven't taken the existing jackshaft apart so I don't know if the bearings are any good. My plan is to press the new jackshaft onto the bearings and replace them in the jackshaft housing. The drive gear has two lock/set screws and is keyed. I was planning on setting the driven side of the CVT next to the drive gear and retain the CVT on with a collar on the outside. The original Yerf jackshaft was threaded, but I purchased a simple keyed shaft.

What am I missing?


Thanks, Patrick

 

[landuse]

Pics??

 

[Pittsjock]

I will post some pictures tomorrow, but....

We had a great time today with the kart.

The original Yerf jack shaft looks to be a simple 5/8 bolt, milled to accept a key and pressed through the jackshaft bearings. I used an aftermarket keyed shaft and used locking collars on either end to keep things in place.

Everything worked out fine, but we got the wrong belt (too big) because the shop we ordered from was out of 7 inch driven clutches and sent us a 6 inch instead. The belt is about 1 1/2 inches too long - worked, but not quite right. We have a proper sized belt (or close) coming next week. I may need to modify the jack shaft mounting holes slightly if the belt is too tight.

Thanks again for the help.

I am already contemplating suspension and brake mods...off the slippery slope I go.

 

[OzFab]

Seriously? did the cvt & belt come from the same place? If so, you'd think thet if they change the driven that they'd think to change the belt too...

Go karts are like Pringles; once you pop, you can't stop