Help! First minibike rebuild


New Member
Hey everyone! So this is my first baja minibike mb165 rebuild and I have a few questions. I purchased the bike with an old (poor running, many part missing) motor in it and after taking it apart I found that the rusted out old clutch was seized onto the shaft. I gave it some love taps with a ball peen hammer and attempted to pull it with a clutch puller and no luck. Which isn’t that devastating bc it hadn’t had a cover on it ever and now is completely rusted over. So now that the clutch and motor are not really in play, I purchased a new predator 212cc engine to swap out with. So here begins my questions... what would everyone recommend going with a TC or just another clutch and chain set? If I put a TC on it I’ve read that they can overheat and melt the clutch so is it really worth it? Where can I get a TC if that’s what y’all think would be more beneficial?
I appreciate all the help or tips I can get in regards to attempting this build as well.


Soak it down with BP blaster or whatever your go to penetrating oil is and try in a day
How are you going to ride it wide open or just putting around Tc are good for putting around on don't listen to they shred belts if it's aligned right it's not a problem the issue your gonna have is gearing will be taller with a Tc once it's cycles out because of the reduction gear on the jackshaft

With the clutch if your gonna be hill climbing it will get hot you not gonna have a very good top speed with stock gearing but still nice power side note your 212 will have a 3/4 shaft and I'd bet the one on it has 16mm or 5/8 shaft

Next is what you wanna do to the engine if your gonna make a monster the Tc will limit your rpms but if it stock will keep you in the sweet spot this part is over my head my motor is stock with a tc and a 60t rear sprocket and 10 t front (somebody tried a 9t now I wanna) will climb steeper hills than I want to and still hit a tree way faster than I want to
Remember speed takes money how fast you wanna go
As posted above, On a TC the belt can over heat and melt/fray/brake if your riding in hills or mountains and the belt slips. If so change the rear sprocket from a 40-50 tooth to a 60 tooth sprocket.
If you replace the centrifugal clutch it can only over heat and slip if your off road. Once cool it will work again.
If you are going to stay with a clutch,buy the needle bearing type otherwise you will be oiling the bushing to prevent binding after every long ride.
These are great bikes and can take a lot of abuse if maintained properly.
There are many articles here on how to mount a TAV, gear ratios and upgrades to your bike and engine.
Make sure with your new 212 engine you warm it up for 20 minutes and CHANGE the oil! There will be casting sand and metal bits from being milled and assembled.
Use a good quality oil as the engine does not hold a lot of it. I ride my bikes hard and change the oil after 25 miles of off road or every five hours of riding.
Trash the CHI-COM spark plug. They are garbage. Get a name brand plug such as a NGK BP5ES or the like for your new engine.


Active Member
For general riding, a torque converter is really a nice way to go. It's faster on starts, better in hills & will still let you ride at about 40 mph on the open roads. A clutch is good for long roads at WOT & long runs, but it's not quite as good as a TC for off-road stuff.

One thing you will need to do with a TC is trim the bottom edge of the plate with a hacksaw, on a Warrior type of frame. You may also need to open the mounting slots for the motor a bit, to shift the motor sideways for the chain alignment. It just depends on your frame & the motor mount from the factory. I installed mine on the motor, then set the motor in place on the frame & used a magic marker to make the line where the TC would hit. Remove the TC, cut it at the line, then put it back together. With the stock motor, there isn't a problem with weakness. Mine is basically at stage 1 with a header, Chikuni & thinner head gasket, but there's been no problem so far after a few years of riding.

Seems like a lot of work, but it's worth the effort & you'll learn a lot about how it works this way. These things are just toys, so learn what you can & you'll be better off if you can do all the work yourself. A lot more satisfaction this way...




Well-Known Member
You may want to shop around if you choose a "TC".

If you are keeping your chain size part of the description should say "40, 41, 420. If a 40 or 41 works so will a 420 chain. Those numbers are chain sizes.
Another important number in the description is 3/4". This is the size of your 212's PTO or as some might say 3/4" crankshaft.

Looks like the prices went back down. Supply must have went back up. The lowest I found when I ordered was $78 a few months ago. These are the Chinese clone of a Comet 30 series TC. They are all over Ebay. If you want you could buy the more expensive genuine Comet TC if you could find the entire kit. Your decision and again, shop around.

Here's an example.