Questions, building a turn track bike for my son

[Malcolm Smiths Dad]

Hi
I want to build a bike for my son to practice corner speed on. He has a Cobra Jr and a Cobra Sr. I can not afford for him to practice on those bikes. My work is going to fall off for the next year and I want to build a bike for him to get crazy fast corner speed on that will be cheap to build and cheap for him to keep up and practice on. Suspension is not a big issue because it will not be a jumping bike and no big bumps I just want him to learn blinding fast turn speed.
He has a Crf 50 with a 88cc piston kit. We love it but I want a motor that I can put in 3rd gear and almost from a dead stop it will come on like a Cobra Sr or a KTM 50 Sr. I want it to jerk his arms. The 88cc we will use for riding in mud and slop and up in the woods.

One Question what about a Z 50 Honda. How ill it handle compared to a CRF 50. How will the big tires effect what I want to do (turn track and figure 8 drills). I have a fiend that keeps encouraging a Z 50 but I am afraid the big tires will not be as good for my small son or feel right compared to the other bikes.

What motor would be recommended? Would you do a kit on the Honda or buy a Lifan or what ever. One note I do want a semi automatic so that third gear can be ore like his MX bikes.

My son is young, 5 years old, and very light but he will grow and he is already blazing fast on the other bikes. If he can ride a Cobra Sr he can ride a fast pit bike. I just can not afford this year to keep the Cobra running except for a few races. Once built I should be able to keep the Honda running.
Since we are home all day this kid rides a lot like 2 times a day. I chase him on a CRF 100 bike and he loves it. He races as much as I can afford to take him and does well.

Please give me your ideas.
Thanks
Steve and Malcolm

 

[coolmodee01]

look for a klx 110

chuck a bore kit on it 134cc or something but keep it auto

this will give you a bike with close to the cobra ergo's

the billet wheels on the cobra's are so nice

 

[Malcolm Smiths Dad]

The KLX is too big. My friends kid has one and it is much bigger and way heavier than the Cobra. It is not seat height to ground but seat to pegs.
The cobra is less than 100lbs the CRF 104 and the KLX 135 or so. It needs to be CRF size.
Thanks by the way.
My son weighs less than 40lbs

 

[coolmodee01]

i dont think you will get the power anywhere close to the cobra's power in a crf

you could probably do bore and stroke work to the crf go to 117cc or 124cc but i'm not sure how the gearbox will hold up at least you will need a heavy duty clutch

good luck

 

[Malcolm Smiths Dad]

What about the Z 50 compared to the CRF in handling?

 

[coolmodee01]

z50 will handle worse for what you want
he wont be able to lay it over as far i wouldn't think

 

[Carlts]

I'm guessing your son is Malcolm Smith?

 

[Malcolm Smiths Dad]

He is Little Malcolm Lee Smith

 

[Malcolm Smiths Dad]

Malcolm Lee Smith, Cobra 50cc 2 degrees Bicycle Trials, Moto Trial - YouTube

Video above

Here is a video from when he was 3, of course he is much much better now.