Small 2T motocross engine with gears

[JariV]

As a tip for anybody. Came across a small Yamaha PW80 kids dirtbike (trainer) and bought it since it was practically free.

It's an 80cc twostroke with centrifugal clutch and 3 speed gearbox. Center of gravity is very low since the cylinder is positioned nearly horizontal. Has reeds also. Aircooled. Electronic ignition. Relatively small in it's main dimensions. Quite good gear ratios.

Original configuration lacks power but tuned the engine by raising compression, opening up the ports with added timing, made new intake and mounted a 23mm Walbro karting carb and welded a new exhaust for it. That opened the engine up very well and now it has substantial power. And being a semi-automatic it could be operated easily with a 3-channel radio. Since not being a true dirtbike can be bought cheap usually and is available propably worldwide. I'm still thinking whether to use mine in a new rc project.

[acc]

jariv has returned

Yep we em (Australia) a few peewee type mini bike (kids motorbikes) engines and being for small kids there usually all without a clutch so its easier to learn to ride on and easier for them to ride

We all know you bought it for an rc project. Don't even try to lie to us.. :p

[Mike Casey]

jariv, really glad to see you back!! Sounds like you have the gears turning already. Hope things have settled down a bit in your personal life.

Welcome back!

[JariV]

Personal life settlement; yes and no. But I will not get into that since that would be off-topic. I've been contemplating to build another big-scaler, yes. But that's as far as I've gone with it yet.

The previous car was built out of passion and I'm yet to find that passion again for the next build. Usually the passion starts when I see something (whatever) that f.cks my mind and creates an image there. That's how it happened the last time.

New Forum looks quite good. But since I also like "the old stuff" then I missed the old Forum which I was familiar with. I see lot of stuff and discussions disappeared and am not meaning the thread about my previous car. I followed quite a lot of threads even if I didn't comment them at all. Sad to see lot of pics gone to oblivion also. Well, things change. New Forum is better than the old one.

[Mike Casey]

The loss of the old forum was devistating. I relied on it to archive lots of great information and now its lost. I am confident though over the next year we will build the site back up to its previouse state.

Cant wait to see what you come up with!

[JariV]

Awfully familiar situation;
I have a tuned engine as mentioned here.

Today I just picked up an old kart with hydraulic discbrakes in front and rear. It's in great condition and only costed me 80$ So that means I have all it takes for the axles and wheels. And I have the Futaba 4PK trans with receiver standing by. And 6 Tonegawa-Seiko servos.

All I'm missing is shocks and a receiver battery cell. And I know where to get them. Somebody is steering me, obviously it's not me but something else...