China Girl Motorized Bicycle - won't start - sell or replace engine?

John H. · Nov 7, 2011

I've run a bike with a Happy Times engine. I commuted with it for one half of one season. Now I'm lucky to get the engine to start, which hasn't been for weeks. Had the bike built for me. Builder not much help.

Have already put in a couple hundred bucks into fixing it (re-spoke job on the rear wheel, new brakes, new seat, yada yada ). Tore the wiring down and re-taped. But now the assist motor doesn't assist about 75% of the time.

Engine is getting gas and spark, carb needle looks OK. Other than that I can't tell. I'm just thinking of scrapping this thing as more a hobby than serious transport. I am no kind of two stroke mechanic, and am tired of spending Saturdays trying to fix it. Is there such a thing as a more reliable two-stroke? Should I replace the engine with another two-stroke, or a four stroke, or do I just sell it and give up?

THoughts, guru's ?

John

Mozenrath · Nov 7, 2011

Re: China Girl - won't start - sell or replace engine?

Have you actually opened up your carb to look inside for problems? I've found that at least 60% of the times I've had problems starting, it usually has to do with the carb. I've had plastic from my fuel jug clog it up, I've had it get gunked up with solder flux(luckily it didn't seem to hurt the engine), and often times the main jet isn't screwed in all the way.

John H. · Nov 8, 2011

Re: China Girl - won't start - sell or replace engine?

Mozenrath -

Good suggestions, and it comes at a point when I had decided to keep the bike and engine, take it to the basement and get into what makes this thing tick, or not tick as the case may be. I think there are pictures on hte forum to use as a guide to the carb.

Thanks!

nightcruiser · Nov 8, 2011

Re: China Girl - won't start - sell or replace engine?

John H. said:
I've run a bike with a Happy Times engine. I commuted with it for one half of one season. Now I'm lucky to get the engine to start, which hasn't been for weeks. Had the bike built for me. Builder not much help.

Have already put in a couple hundred bucks into fixing it (re-spoke job on the rear wheel, new brakes, new seat, yada yada ). Tore the wiring down and re-taped. But now the assist motor doesn't assist about 75% of the time.

Engine is getting gas and spark, carb needle looks OK. Other than that I can't tell. I'm just thinking of scrapping this thing as more a hobby than serious transport. I am no kind of two stroke mechanic, and am tired of spending Saturdays trying to fix it. Is there such a thing as a more reliable two-stroke? Should I replace the engine with another two-stroke, or a four stroke, or do I just sell it and give up?

THoughts, guru's ?

John

My thoughts, these 2-strokes are all about the same no matter what the name is on them. Most of them need a little tweaking to get running good, once you do that they should be fairly reliable, and you should be fairly knowledgeble at that point to fix her when she breaks.
The carb is one good place to focus when you are having starting problems, and also the spark plug, wire and cap. What does the plug look like when you pull her? Have you cleaned the air filter? Sometimes they soak up oil from blowback in the carb... And make sure everything is air tight, exhaust, intake, and carb mounting.... Make sure you turn the fuel valve off when you park the bike....
good luck, post back more details and we will try to help you out....

Mozenrath · Nov 9, 2011

Re: China Girl - won't start - sell or replace engine?

Oh also, there's the possibility that the kill switch is faulty, which is somewhat common. Mine works fine, but a faulty kill switch might short out the connection and prevent a good spark. Next time you try starting the engine, disconnect the kill switch entirely and see if anything improves. If the engine starts then you're all good and you can just stop by stalling out the engine.

The carb is fairly simplistic, assuming you have the NT carb. I don't know much about the CNS, but I love my NT carb. It's such a simple mechanism that once you open it and get a look at it, they mysticism of it will go away and you wont be afraid to open it and diagnose a problem.

John H. · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

Sorry for getting back so late, but I found it.

The wires into the kill switch were stretched out so bad that it was putting the kill switch in the "Always on" position. I pulled them back a bit, and now it starts right up.

I'm going to find a permanent solution for that, may remove the switch, or re-wire to a double-throw, plus spend a bit of time cleaning the carb and checking the plug.

Thanks guys.

John

Al.Fisherman · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

John H. said:
Sorry for getting back so late, but I found it.

The wires into the kill switch were stretched out so bad that it was putting the kill switch in the "Always on" position. I pulled them back a bit, and now it starts right up.

I'm going to find a permanent solution for that, may remove the switch, or re-wire to a double-throw, plus spend a bit of time cleaning the carb and checking the plug.

Thanks guys.

John

Ummmmm....very strange since you mentioned that you HAD spark.

John H. said:
Engine is getting gas and spark, carb needle looks OK.
THoughts, guru's ?John

BarelyAWake · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

John H. said:
...The wires into the kill switch were stretched out so bad that it was putting the kill switch in the "Always on" position. I pulled them back a bit, and now it starts right up...

Intermittent electrical gremlins are the worst >.<

John H. · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

I had spark . . . give or take which way the handlebars were turned.

How's that for intermittent?

Al.Fisherman · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

John H. said:
I had spark . . . give or take which way the handlebars were turned.

How's that for intermittent?

intermittent
[in-ter-mit-nt] Origin
in·ter·mit·tent
[in-ter-mit-nt] Show IPA
adjective
1.
stopping or ceasing for a time; alternately ceasing and beginning again: an intermittent pain.
2.
alternately functioning and not functioning or alternately functioning properly and improperly.
3.
(of streams, lakes, or springs) recurrent; showing water only part of the time.

If you had said that you SOMETIMES have spark and other times no spark, we could of diagnosed the problem immediately. I would of posted this....
https://docs.google.com/document/d/1aBeJuoS--VQWwXysc07rpscTUbPzgc93xjiQBgsyFjc/edit

The_Aleman · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

Al.Fisherman said:
intermittent
[in-ter-mit-nt] Origin
in·ter·mit·tent
[in-ter-mit-nt] Show IPA
adjective
1.
stopping or ceasing for a time; alternately ceasing and beginning again: an intermittent pain.
2.
alternately functioning and not functioning or alternately functioning properly and improperly.
3.
(of streams, lakes, or springs) recurrent; showing water only part of the time.

If you had said that you SOMETIMES have spark and other times no spark, we could of diagnosed the problem immediately. I would of posted this....
https://docs.google.com/document/d/1aBeJuoS--VQWwXysc07rpscTUbPzgc93xjiQBgsyFjc/edit

The problem did get diagnosed immediately. Mozenrath was on top of it, OP was just slow getting back.

You seem to be out of touch lately.

nightcruiser · Dec 12, 2011

Re: China Girl - won't start - sell or replace engine?

you kinda need to have spark even when you turn the handle bars!

I guess you know now, when your bike wont start it's a good idea to disconnect the "kill" switch and start from there...

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China Girl Motorized Bicycle - won't start - sell or replace engine?

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