250cc Dirt bike QS3000 build

[Clanarn]

History



So in 2017 I converted a 1999 derbi senda. That was my first “high power” build. It used a qs273, sabvoton 72150 controller and a soldered 18650 pack with about 1.5Kwh. It was awesome and could outrun most of my friends scooters doing 80kmh. But I wanted more power and something more durable that could withstand actual abuse from jumps, dirt, rain and long commutes. I've also decided to make it mid drive cus jumping with a 20kg hub motor just aint easy.

My first idea was to use a honda crf250, so I bought a frame along with rear shock in great shape for 100usd. But after looking into what it would cost to buy all the rest of parts to make it run came to the conclusion that it would be too expensive(for now atleast ). Therefore i decided to go with another solution.

Specs
Qs 3000w mid motor
20s16p Tesla MS cells

 

[Compoundbike]

Following since im also interested in such build.

 

[Clanarn]

Build


This became the solution. It's a chinese dirt bike 250cc with a ride height of 90cm, not as large as a “real” 250cc but works for me. New bearings for the suspension link ordered and the qs mid motor arrived.

 

[Grantmac]

How much peak power are you thinking? Estimated weight?

I was considering the same motor into a youth sized frame (KX100/105SX/CRF150RB).

 

[Clanarn]

15-20kw. Depends on which controller i choose. Have been looking into ASI Bac, Votol EM-200 and sabvoton. The fact that it is going to be heavy is all i know right now. Stupidly heavy steel frame.

If you want it chain driven let qs know they will cut the shaft to fit 428 20mm sprockets for free which is nice.

 

[Grantmac]

It's steel? Yeah that'll add up for sure.

Thinking under 250lbs?

 

[Clanarn]

Probaly just below

 

[j bjork]

Interesting, any progress?