Help me choose an engine!!!

[Ockie]

Hello everyone!

I need help deciding what engine I should use for my next build. My bike setup is an aluminum skyhawk gt with the motor mount, 26"mag wheels with 3" white boa slick tires, and a 26th sprocket. I am going back and forth between mainly two motors, a modified 66cc china girl or a denardis 50cc or 60cc engine. I really want to be able to hit 60 mph and right now I am leaning toward the (ktm) denardis 50/60cc motor. Can anyone give me some insight on what would be my best option for this build? Thank You!

 

[TheNecromancer13]

You're not going to hit 60 with a little 66cc 2 stroke. 40, maybe, but that would be after many hours of tuning and lots of upgrades. Also if you put an engine powerful enough to hit 60, the aluminum frame might not do too well. If you want a bike that can do 60, people have used the 212cc predator and the 125cc lifan, among others. I'm currently building one with the lifan.

 

[KCvale]

My bike setup is an aluminum skyhawk gt with the motor mount,
26"mag wheels with 3" white boa slick tires, and a 26T sprocket.

A 26T direct drive rear sprocket?
Are you just building this to break some 'silly' records, or to actually be useful in real life operation?

I really want to be able to hit 60 mph and right now I am leaning toward the (ktm) denardis 50/60cc motor.
Can anyone give me some insight on what would be my best option for this build? Thank You!

Hi Ockie, yes I can give you some insight, a real eye opener...
You will NEVER see 60mph so please, just concentrate on the parts you have and what you can get from them.

Go with a real Skyhawk GTA5 engine.
http://www.bicycle-engines.com/2-Stroke-AngleFire-Engine.html

Put a 48T sprocket on the rear, you'll be able to ride in the mid 30mph range.

If you want motorcycle flexibility and speed from a bicycle you need gears.

That ran low 40's with no engine mods, but more importantly, it has the brakes to stop it!

The GT2A frame has V-brake mounts, use them or go disc bud as the 'need for speed' urge means more consideration of brakes.

 

[ultralight01]

Keep in mind the above bike has a shifter kit for more top speed.
Use a four stroke. Try a predator 212 or 79cc. Or a 50cc honda clone.
It all depends on the bike. The 125cc lifan and predator 212 need big frames.

 

[Ockie]

https://m.youtube.com/watch?v=bKzeCSauErU

 

[ultralight01]

Hehe. You know why he needed that long stretch of road right?
He has a minuscule sprocket on that back wheel. It takes up to a minute to get up to that speed.
Commuting will be very hard, you will find yourself pedaling most of the time even with a ratio meant for 50-60mph. The engine will have no power and you won't be able to move until your going over say 10mph. Then you Will need to help the engine by pedaling till it gets up to speed.

In that video you can see he's barely going jogging speed under the engine's initial power

 

[Ockie]

I understand all this and I was originally just going for a "drag" setup but now I have other plans. I forgot to edit my original topic and mention that j was probably going to change it to a larger one. I have been think about this for a while and I will probably go with the Denardis 60cc liquid cooled motor with a sbp shift kit and make/get some custom mounting brackets. Since this engine get more than double the 66cc chinagirls, does anyone have any hd chai rigs that could fit some 26" mag wheels (disc brake version)? Thank you!

 

[KCvale]

If you want a motocycle with pedals, build a MotpPed.

It'll set you back ~$3K but it will do what you want safely.