Howdy from Aggieland

[BrianD51]

I had the good fortune of stumbling upon this site about a month ago. I have a 14 year old niece who I have introduced to the world of racing, turning wrenches and anything that goes fast. We were talking about my childhood and she is always fascinated when it comes to all motorized things I had when I was her age. Long story short, I bought her a go kart because I thought it would be the perfect thing to start with and also it could be a project for us to do together.
I cannot wrap my head around how a 44 year old man who was a school bus / diesel mechanic for 15 years and has 80k in tools can have such a hard time doing the same thing he would have been able to do 30 years ago with nothing more than a crescent wrench and a pair of pliers.
Hopefully, with y'alls help my niece and I can bring this kart back to life and she can experience the same feelings of freedom as I did when I was trail running when I was her age.
Here's what we're working with. I believe it's a Manco and it is absolutely beat up. The motor is a 196cc Baja, and the carb needs cleaning and the float is stuck open. The air cleaner is in pieces, and the output shaft is too short to fit the new CVTC that I had to buy because both pulleys on the old one were wore out. There is no kill switch wiring at all, and I'm not sure this thing ever had brakes. Someone gave the motor a brushed on paint job along with the rest of the kart. The only good thing so far is that the engine fired on the first pull. It's going to need plenty of work and I plan on putting significantly smaller drive tires on.

Here's why I've been lurking. The new belt drive isn't compatible with the crank on this motor, so I dropped money on an chain driven centrifugal clutch. I moved the live axle components around a little to get everything lined up properly and the first time we tested it, it barely moved and then smoked the clutch. From my math we currently have a 6:1 ratio and I'm still on the fence about whether to try to rebuild the motor or just drop a bit of money on a new one. I never messed with a belt drive other than on a snowmobile, everything else I had was chain driven. I would like to keep the chain drive since it's simpler, but I'm not sure what's a good ratio for mostly trail/ flat riding?
Any advice is greatly appreciated as I'm trying to decide on whether I want to throw a jackshaft with a gear reduction on it.

 

[panchothedog]

Welcome to the forum, and the world of go karting. I think your tires look fine. But a centrifugal clutch will never work with big ones like those. With the torque converter, or CVT it's a perfect setup. If it had a torque converter on it before, then there's no reason the new one won't work. When you put the driver onto the crank shaft ( it goes on in two pieces ) it is a very common to only a 1/2" of shaft left to install it onto. Sometimes only half of that. Seems crazy, but it works if you do it right. Get a bolt that will grab as much thread of the female of the crank without bottoming out. Every setup can be different. ( I have 5 vehicles that use these ) At times I have cut down a 3" bolt, being too long, but the next size shorter didn't get all the thread that was possible. In with the torque converter there should have been a very thick washer that goes under the head of the bolt. Very important to use it. Mock every thing up, run the kart with the tear tires off the ground ( Jack stands ) and when you are satisfied all is good, load the bolt up with blue thread locker, hold the clutch with a strap wrench, and tighten to 25 lb. ft. It works, believe me. Fix your carburetor if you want. They are cheap enough that I buy new ones. Everything you could possibly need for your kart and it's engine can be purchased online from Go Power Sports, or O.M.B. Warehouse. Those are two of the bigger kart supply shops. There's 3 or 4 others just as good. I mentioned these because I have been trading with them for years. Any and all questions or problems you run into, fire away. There are dozens of members on here with collectively hundreds of years of experience with these things more than willing to help you out. It doesn't exist, what at least one of us hasn't seen.

 

[BrianD51]

Hi Pancho, the problem I've got is that the output shaft is about a 1/2 inch shorter than the drive pulley, also it's externally threaded and not drilled and tapped for a bolt. I don't really like the drive tires either, they are massive and I'd like to cut down on as much weight as I can, not to mention the sidewalls are cracked and both are completely dry rotted.
I'll take some pictures tomorrow.
Thanks!

 

[Master Hack]

Is the output shaft (crankshaft) tapered? If so l believe yer gunna need a different engine. I could be wrong and l usually am.lf So soneone smarter will correct me.

 

[Functional Artist]

Howdy &

To get more better info, we need pics
...of the motor
...of the end of the crank shaft
...& of the CVT that you have

 

[Denny]

It sounds like is a trash pump engine. It has the wrong crank. By the time you get done replacing the crank and carb you’d be cheaper and better off switching to a predator. Then you could switch to a TAV II 30 series CVT. Switching to smaller tires will not make that kart better. It will ride rougher and not handle or go off road any better.

 

[BrianD51]

When I originally was going to buy the kart I told them I didn't even want the engine. But when we picked it up they hadn't take it off and I tried to get them to take it but... It's not a bad motor, just got abused and most likely poorly if maintained at all. It's your run of the mill Honda clone, but I'm not trying to throw shade at Baja Motorsports because it sat long enough that the tires on the cart went bad/flat, but fired right off first rip only needing a tank of gas.
As for the CVT, it had a series 30 drive and driven pulley. They were toast [of course] so the plan was to throw the series 30 kit on. Had to cut off the original jackshaft tube because there was clearance issues with new setup. When I realized the shaft was going to be too short, I pulled the belt drive off and went with a centrifugal direct drive. The plan was to save the CVT in the event that I did buy a different engine, I even thought about using the backing plate and jackshaft to make it a split chain drive so I could mess around with the ratios that will fit my nieces driving style.
But yeah, if I can't get pics Thursday, I will get them Fri.

 

[panchothedog]

If the crank is threaded on the outside, then it's not a typical Honda clone. There are dozens of manufacturers of the clone engine and they all have a internal threaded crank shaft. 5/16" x 24 thread. If you didn't want the engine in the first place, go to Harbor Freight and buy a 212cc predator. For $150 for a brand new engine with a garuntee you can't do better. Get a $70 30 series plate style torque converter from Amazon ( they're all the same in quality ) and put some inner tubes inside those old cracked tires. While you're at it slather on some armor all onto the side walls. ( you'd be surprised to see some of the dead ones I've brought back to life ) . Your and the niece will be ready to go. The torque converter is a fully automatic transmission. She can put around all day at 5 or 6 mph. You can hold it wide open and even with the governor completely stock it will probably hit 30 mph. Either way the torque converter is the way to go. 6 to 1 gear ratio is perfect. There are thousands of karts set up just like that. For your own good FORGET about a centrifugal clutch. They are designed for something completely different.

 

[ezcome-ezgo]

Also: genuine Comet Belt! You're welcome Denny.

 

[BrianD51]

I already have the 30 series CVT sitting in the box had the back plate and driven pulley all installed before I realized the drive pulley wouldn't mate up with the output shaft. The plan was always to put a different motor on because I want something with electric start, not so much for the electric start as much as I want the ability to wire up a headlight that I don't have to worry about recharging or replacing a battery. But anyway, I think I'm just gonna pull the motor, and while I'm at it I'll probably strip down everything and give it a decent rattle can job.

 

[BrianD51]

Pics as promised:

 

[Denny]

A clutch will not work on that set up, but you already found that out. Drill the center of the crank and tap it for a 5/16” bolt and you should be golden to put the TAV II on.

 

[ezcome-ezgo]

Those front wheels look suspiciously hand truck/Harbor Fright hazardous.

 

[BrianD51]

Denny, I've gone back and forth on whether I want to drill and tap the shaft or just swap the motor. I'm most likely going to swap it and that way I have a true clean slate to do whatever I want with it.
And Ez, yes and yes. And the left wheel is so bent out of shape I'm surprised it isn't sitting in a corner somewhere sobbing uncontrollably. Which is why I have just kinda resigned myself to putting new tires, wheels and hubs on all 4 corners.