Predator 79CC FRICTION or OTHER motor need help from the pros


New Member
Jun 4, 2019
Hello there, I am new to gasoline powered bikes, Years ago i built a Lithium brushless, but got out of it.

I just want to cruse on a motorized bike, simply and not get too involved. Speed doesn't matter just a little engine roar, ill be pedaling the whole time as well with it. System must be 4 stroke, i dig the sound and intend to use regular gas.

I will try my best to be clear and not redundant i don't want to waste anyone's time, and before i begin i sincerely thank you for taking a time out to help a total newb/novice.

I have decided i want a simple friction drive set up, I have a few bikes and will most likely ping pong to them.
I dig the friction set up and cant wait to set one up.

I noticed MANY friction kits on and i am eager to buy one
Having said that i am looking for a drop in motor solution, I would like the motor to be cheap to outright replace, and also be able to get parts like clutches, and carbs for it

Would that 79cc Predator motor drop into one of those friction transmissions? (they seem to have a lot of models with various sized clutch bells)
I don't see a way of verifying it in a spec sheet.
It also appears that the Predator does not come with a clutch, i sadly do not know what clutch to buy that would connect to the shaft.
I kinda wish i could just add the parts to cart and charge my credit card and then begin assembly, I have a lot on my plate right now in life, and don't have the time to do serious modding welding and fab work.

I know about the:
to increase the shaft diameter, but...i still dont know what clutch would fit on it, kinda lost.

If the predator is just not the best option, Id like to know, perhaps there are other Motors out there that are simple drop in solutions and are reliable for many miles?
the predator is VERY cheap...a huge plus

Anyway i dont want this initial post to go on too long, i appreciate your time and look forward to hearing and learning from you.
Last edited:


Well-Known Member
Sep 4, 2008
I have never owned a friction drive. But I will answer you.
-clutch diameter determines whether an engine fits the friction transmission.
-you need a clutch so the engine can idle at stop signs and stop lights.
-one of the biggest advantage of friction drive is that you generally do not need a transmission. You attach a drive roller to the output shaft on the clutch. The roller⁵ contacts the tire. No tranny.
- I Realize that the predator engine is affordable, but very heavy. Try a 49cc 4t engine from one of the sponsors. The bike will be much easier to handle with a lighter engine.


New Member
Jun 4, 2019
thanks, I saw many from the sponsors that look better and lighter. I was kinda keeping the weight of the predator in the back of my mine lol


Well-Known Member
Dec 29, 2008
Also got to remember the rpm's 49 will rev to 7,000 verses 79 around 4,000, your speed will be about the same. Rev higher and smaller roller with 49...........Curt