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Bigredgasbike

Bigredgasbike

New Member
Alright, you guys have helped me before, so judging by your helpfulness before im sure im in the right place. My bike gets normal power for the first 60 seconds of operation, then it runs at half power, fluxuating a lot, until it gets a break, i think it might be the carberator, but it may just be that i bought a cheaply made engine kit. i bought the kit about a year ago and have been riding it ever since, im almost ready to give up and buy a better quality kit (i know mine is low quality because some of the parts broke a year ago when i bought it and i had to improvise parts, which worked fine) so if anyone can help me here id appreciate it, if not, woohoo i get to put together a new one!! =) dance1
 
All these engine kits are cheaply built with inferior parts. First thing I get to do when I get a kit is to replace the hardware, torque everything and use loctite. Then make new brackets, use a marine fuel tank sealer to keep the tank from rusting and prevent leaking fuel around the tank studs. There's more but I'm too tired to list them.
 
Are we talking about a cheap Chinese 2-stroke?

It sounds to me like fuel starvation, a bad electrical connection in the harness, a bad mag, or a bad CDI.

If it is fuel starvation, for the first 60 seconds the engine is burning up all the available fuel in the carburetor, then it stumbles on it's face.
Check for good flow out of the fuel tank, a clogged fuel filter, or debris in the float needle valve.

Check the connections between the mag wires coming from the engine and the CDI box.

If you soldered them origionally you should be ok, however a cold solder joint can fail over time.
If you are still using the factory plug in connectors, cut them off and solder and heat shrink the connections together.

If it is a cold soldered problem, re-solder the connections only this time around, get the actual wires hot enough to melt the solder, don't just melt the solder around them.

If it is a bad mag, it is heat related. As it heats up the copper windings expand and short out internally.
It also could be a bad solder joint on the mag. They can get thermally sensitive too.
(once again, a cold soldered joint)
Check where the blue wire attaches to the coil. The solder should be relatively smooth and a dull gray color. If it has a wrinkly surface and a whitish color to it, it needs to be re-soldered.
Also check the black wire where it is soldered to the ring lug (a replaceable terminal with a bolt going through the center of it).

If it is the CDI, once again it is thermally related, you can only replace it with a known good one.
 
it has been running fine all year up until recently, yes it is a chinese two-stroke, and the electrical system is fine, although i should probibly clean the spark plug, and i will also look into the fuel starvation thing, i will repost as soon as i have time
 
it could be as simple as an airleak. when the bike starts losing power, try lifting the choke arm up 1/4 to 1/2 of the way up. if the bike regains power it's a leak.

replace the intake gasket, get an O-ring for the carb, and make sure it's all mounted tight and sealed up.

while you're at it, clean all the oil out of the filter.
 
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