China Motor Problem

Just a guess do you have a light or something hooked up to white wire that runs a night.

What spark plug are you using?

You have fuel leaking, not shutting off the fuel valve when you get to work?

Find the topic for setting your carbs float level, if it leaks fuel out the overflow and your carb tilts forward it may be leaking fuel into the crankcase too.
One way to get that fuel out is turn of the fuel and pull the plug, then pedal up and down the street a couple time with the throttle open. That will usually get all the crap out.

dawa31 said:

Ok everyone here's the deal.
Just before winter it started to get me the 3.5 miles to work but wouldn't get me back home at night. I figured it had to be the cool damp air at night.
Any help would be GREAT.

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What does "but wouldn't get me back home at night." mean?
That is really vague. How about helping out with specific details?

Perhaps heat soak related in the electrical ignition side? Does it run better when the motor is cold but crappy after it has ran awhile?

Try testing for spark when it is in the not starting mode.

Get rid of the Chinese spark plug and get an NGK.
The plug may have an intermittent fault in it.

It's great to have known working CDI's and magneto's so you
can swap them out to diagnose a problem.

dawa31 said:

The spark plug is a Weixing No.1 Z4C Super Power. And yes I do shut the fuel off when I get to work.

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It could just be a vapor lock if you store your bike indoors at home and outside on rides, take a rag with you and pop the cap after it being in parked in sun, that's what causes vapor locks if the cap don't vent.

The other thing is your 'Weixing No.1 Z4C Super Power' plug.
Never heard of it but sounds like a snow mobile plug because the 4 in the number is the heat dissipation range number.
The higher the number the more it dissipates heat from the head, here in the desert I run 7 and 8's, 4 is for like Alaska, it traps all the head heat it can.

Just buy an Iridium plug, NGK BPR6HIX plug and try it.
http://SickBikeParts.com has them and I keep them as staple in my shop.
NOTE! It is too long for some cheap kits or if you have done 'higher compression mods!

To test anything electrical you need a multi-meter, Radio Shack has them for under $10.

There is no real way to test all of a CDI but one test you can do simple:
Set you meter to continuity at a 20K ohms scale.
Put the red+ probe on the black CDI ground wire.
Put the black- probe in the end of the spark plug cap where the plug connects.

You should get ~692 Ohms resistance +-100.
If you get nothing or 0 then the CDI or plug wire is dead.
A quick way to check which is unscrew the plug wire from the CDI and test right at the CDI out to the plug wire.

To test the Magento on the motor unhook the CDI and leave you meter where it is (20K) and put the probes across the top ground and spark (white) wire just below it on the mag. It don't matter which way

If it shows no resistance (open circuit) then that winding in the mag is fried open.

You may not have not known anything about electrical stuff when you started this topic but you sure will by the time you are done with it ;-}

Here' a link from forum member AI.Fisherman on how to test your electrical system. Includes a link on how to use a multimeter:

https://docs.google.com/document/d/1aBeJuoS--VQWwXysc07rpscTUbPzgc93xjiQBgsyFjc/edit

Harbor Freight sells them too and sometimes they give them away for free.

Good Luck,

Chris
AKA: BigBlue

So did the new electrical parts fix you up?

dawa31 said:

The spark plug is a Weixing No.1 Z4C Super Power. And yes I do shut the fuel off when I get to work. Actual before I get there that way some of the fuel is out of the bowl. Lets see how to explain won't get me back home???? I turn the fuel on and start to peddle our of the parking lot, and pop the clutch. Fires up for a few moments, and sputters till it stops running. Peddle down the street, pop the clutch, Fires and sputters to a stop. There is a small down hill on the way home. Pop the clutch at the top gravity forces the engine to stay running but at the bottom it stalls out. I might also tell ya with out touching anything the next day it starts just fine runs great, but again to the store maybe 1 mile away but not home.

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Sounds like a stuck float valve to me. Leaking fuel drowns it out, right? Does it run better if you shut off the fuel? Check it out. Clean the needle and seat and get a fuel filter in the fuel line.

If you have any further problems, make sure your gas cap vents alright. Mine would die out sometimes, and it's because there was a vacuum in the tank. I had to drill a small vent hole.