[Rod_Lenghtens]

Hi guys/girls,
First time poster from Aus.

picked up a "chopper" 49cc aircooled which is 2 years old and riden 3 times for $100au. took a bit to get her started but now running is a bit of a hoot.
just a question regarding 2 strokes, and i appoligise if i am in the wrong section for this. i'm a carby 4 stroke car motor man but never worked with a typical 2 stroke and need a bit of help. the old girl gets 15mph down hill and 10mph just uphill on a 1 in 5 gradient but splutters at highspeed.

carb has an idle adjuster and a mix screw, is the mix screw just for idle mix or can i mess with it to get a bit more go out of it, and how do i tell if it is lean or rich?

mix of fuel and oil is errr about 1:20 as written on the tank. any help is appreciated

and loving the site!

[SpyGuy]

Nice bike .... I've got a slightly larger mini-chopper I'm trying to get running again, myself.

Check your spark plug to find out if it's running rich or lean. Whiteish/grey is too lean, pitch black/dark brown is too rich.

could you please show a few other shots of the bike, and at least one of the engine? just so we have a better idea of how to help out. a good shot of the carburetor area would help, too.

[dragonkeep2000]

the top screw is for the idle and the lower is the air/fuel mix.....these carbs off these motors have a problem after a while with the seal between the carb body and the primer body going bad..........that bike has a 43cc engine normally from the factory..with a 10.5mm carb....if you want to keep the engine prety much stock you should go up to a 15mm carb...you will notice more power from it.....they come pre adjusted from the factory...just bolt and go.........depending on if you did any mods to the bike engine you may have to adjust the fuel flow air mix screw..................it is known as a C1 mini chopper if you want to look up replacement or performance parts..................hope this helps.........

[Rod_Lenghtens]

sweet reply champ that does help a lot.

so she is a 43cc, that would explain why it has trouble carrying my christmas weight around.

cheers man

Dan

EDIT: pics added



and carb close-ups





pulling the spark plug is proving to be a pain in the butt as tha whole inlet has to come off

[StrayDawg63]

That's not a 43cc motor. That motor is totally different than the 2-stroke motors we have here in the states on the mini choppers. It has a twin cylinder 2-stroke motor in it. It looks like it maybe a reed inducted motor to. I'd like to see more pic's of the motor of both sides. There maybe some markings of the size of the motor at the base of each cylinder or stamped into the case some where.
Since the chopper is acouple years old and only riden a few times did you clean the tank and carb out? With it sputtering at the top end it sounds like it's running to rich so try resetting the mixture screw to 2 1/2 turns out.

[dragonkeep2000]

well i was mistaken....it is not a C1 mini chopper.........but it still is a 43cc engine....these bikes were sold by the SunL corperation here in the states... i made the mistake of buying a sunl product b4 anyone told me how much of a piece of garbage their products were......they buy their stuff from the lowest costing supplier and try to sell for the high price and they say they service all their products but that is b/s i have a dealership of sunl 4 hours from me and they don't even carry parts for the bikes they have to send out to china and you have to pay for the shipping of the part/parts you need...........i myself got it running and sold it quickly.........the carbs are the least of the problems with these bikes....the one i had , had a belt driven transmission , for which they do not even make a replacement belt for it .....i hope you have a better time with your bike than i did have with mine......most of the C1 parts other than the engine will fit your bike the engines are not the same only the carbs are...........

[z28bill]

Originally Posted by dragonkeep2000

well i was mistaken....it is not a C1 mini chopper.........but it still is a 43cc engine....these bikes were sold by the SunL corperation here in the states... i made the mistake of buying a sunl product b4 anyone told me how much of a piece of garbage their products were......they buy their stuff from the lowest costing supplier and try to sell for the high price and they say they service all their products but that is b/s i have a dealership of sunl 4 hours from me and they don't even carry parts for the bikes they have to send out to china and you have to pay for the shipping of the part/parts you need...........i myself got it running and sold it quickly.........the carbs are the least of the problems with these bikes....the one i had , had a belt driven transmission , for which they do not even make a replacement belt for it .....i hope you have a better time with your bike than i did have with mine......most of the C1 parts other than the engine will fit your bike the engines are not the same only the carbs are...........

Have the same bike looks like a vtwin even metal left side a blank. Carb only idle adjust don't touch mixture. Bought mine not running new carb 43mm, solenoid, and magneto finally running. Putting a different motor on it not enough oumff.

[dragonkeep2000]

i hated mine especially the drive belt transmission.........i was glad when somebody bought it off me....

[alfieralph]

Ive just aquired one of these bikes..... Having read the last couple of post im beginning to wish I hadnt.

This is my first pocket bike, its a non runner. Just needs a couple of piston rings to get it going. I can confirm that one of the cylinders is a blank. The cylinders are 40mm diameter, although the guy who sold it to me swears its a 50cc engine.

Im having difficulty getting a ring set for this engine, I have no idea what engine it actually is. There are no plates on the bike, just a serial number stamped onto the casing. I took a chance and ordered some rings from a local mini bike shop and they were wrong. Stuck with this thing now. ufff.

al

[dragonkeep2000]

40mm piston rings make it a 43cc engine , 44mm would make it a 49cc engine...the rings for a cateye bike engine will fit it........

[alfieralph]

Thanks for that. I did manage to source some parts from a local scooter agent in the UK. They had various piston kits in stock with the dimensions listed. i did have to modify it slightly in order to fit the conrod but all is well and she seems to be ok.

I will post some pics when the project is complete. I gotta sort out the wiring out next cos the guy who i brought it off deceided to rip it all out.

[msthebadguy]

can't even get mine started

[Rod_Lenghtens]

wow long time since i have been on here!!!

i moved far away where internet and riding my pocket chopper was only a dream...

my chopper is doing a-ok for the time being and despite a few desigh flaws and cheepness of the item its still great fun - not disappointed at all!

knowing it is a 43cc is a real bummer but i have managed to do a little work to it

basically it started when i thought i'd strip the rear cylinder off because it does nothing (still have not taken it off) and thought of a "why not" and pulled down the whole inlet system to give it a bit more go.


i noticed the inlet was basic in that it was a honed out tube of alloy with a section which flanges to the inlet port of the cylinder head.

i decided to do a bit of porting on the inlet manifold to make the transition a bit smoother.

the end result was very effective in that the inside edge was completely smoothed out and all the bad casting marks were removed.

little gains were felt after this although it had a bit more strength about mid throttle.

i thought i'd look at the exhaust and same thing with the standard manifold. i smoothed it all out and made the inside really clean. i turned to the exhaust and found the exhast was just a smaller diameter pipe in a larger flange welded in the outside. restriction was obvious.

took the tungsten bit in a drill and honed out the flange to give a smooth transition area.

the results were noticeable - although it still maxes out at around 15mph it gets there far quicker!

if you wrench the throttle while moving it picks up really well!

ive also taken the aircleaner top off and turned the cap upside doen to make it have a clapping induction noise.

next i'm on the lookout for a front sprocket

currently there is a 18 tooth one on there with a 33 tooth rear

finding one is proving hard but have tracked down some 20 teeth ones but for a 05T chain - does anyone know what chain type it has on there? i think it is a 05B unfortunately...but being us i would have though it would be more imperial. using a tape measure ti fund out is still too inaccurate

[Rod_Lenghtens]

Originally Posted by msthebadguy

can't even get mine started

mine is a ***** to start if you do it wrong - once its flooded walk away and caome back after 10 mins

1 put a band or something over the rear brake leaver to hold it down

2 full choke

3 prime the carb once

4 crank it using the pull start (my electric is shagged) and wrench throttle

it only takes 2 of these and it goes no worries