49cc mini dirt bike knowledge

[quick kiwi]

Now i've had a look on the net and i've found little bits and pieces on the Chinese made pocket bikes.
i have one the i got from a mate because the snapped it in two. A couple of plates, a few pieces of rebar and a welder later it was fixed, noticed the tap was leaking (common problem) so i made a nylon nipple to take it's place. Took it out and snapped a clutch spring, found a new one and that was fix. then riding one day the back tyre blew, needed a new tyre and tube. When i got it home i noticed a sagging shaft coming out of the reduction gearbox (bearing was toast) so i went looking and then gave up for a while (1 year) in that time someone had stolen the motor, kill switch and twist grip (thank you assh***), so i went looking found everything i needed to get it running on trade me. a bit of money and time later i now have a little pit bike that may last a couple of good rides before it dies again.

but i want to know more.
i want to end up building a new frame and buy the best parts for something i can really have fun on. which brings me to things like gear ratios, carb design, air filter design, frame designs and so on.

other things i would like to know is where to get good part/motors.

things i have found so i hope it may help others. i will add and revise when i find out more and i will try to cover as much as i can.
please note it is just a few scraps from here and there.

49cc Spark plugs:
China: L7T
CHAMPION: CJ8Y
BOSCH: WS7F
NGK: ZBM6A

Spark Gap:
.020in. - .023 in.
0.5-0.7mm (it says from another source)

Magneto to coil clearance:
.010 to .020"

oh and hi this is my first post.
hope i help and get help.

[DanielM8]

Welcome to KB.

Aliexpress.com .. Cheap parts straight from china.. With quality to match. Stormparts.co.nz also carries a lot of stock for 50cc vehicles


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[toebug]

I buy all my gear from www.newmanz.co.nz. I have found their packages to be as good if not better than what is available on retardme and I have now built about 20 pocket bike/go-peds. There are probably also heaps of frame designs out their as secondary schools and polytechs build them for their student projects and have a races series at manfield.

[quick kiwi]

thank you, thank you. didn't know of these sites.
what would the best bore for the carb be? 13mm 14mm 15mm 19mm? and what style of carb is the best performance wise? i have come across curved slider, flat slider and butterfly. i have never really been taught any of the basics of what the different styles of the same part do, i've been more of the fix it up and get it to run with what its got. so this is where i am a total noob.
and another weak point of mine is the sprockets, what happens when add more or less teeth on either transmission sprocket or wheel sprocket? or adding a intermediate gear between the engine and transmission sprocket?

[russd7]

only thing i can offer is encouragement, sounds like you havin fun keep it up definately keen to follow how this progresses

[Akzle]

49cc Spark plugs:
China: L7T
CHAMPION: CJ8Y
BOSCH: WS7F
NGK: ZBM6A

Spark Gap:
.020in. - .023 in.
0.5-0.7mm (it says from another source)

Magneto to coil clearance:
.010 to .020"

oh and hi this is my first post.
hope i help and get help.

bit like a lawnmower, eh.

I hate chinese shit with a passion. So i'm'a go ahead and recomend buying a big boy chainsaw motor, then running it on ethanol for maximum lulz

butterfly styles carb gets my nod because theyre easiest to slug. More stuff in= more lulz.

And never mind a muffler, dump pipe that bitch. Maximum loud = maximum lulz.