Motor won't start

Take off your magneto cover and check in there, make sure the magnet doesn't slip, check the solder and wiring there?

Or it could be your CDI, when you checked the ohm's on that, I believe I guess, that you are just checking the coil ohm'age, not the rest of the parts inside the CDI.

I helped as much as I can, someone else can help you more.
I'll pass the torch to someone more knowledgeable and have dealt with this before.
Hope this gets figured out, tell us how you fixed it.

Try picking the back wheel up off the ground and kicking the bike over with the pedal,,its much easier than walking around and trying to see a spark IMO,,and make sure the spark plug is grounded out on the head/jug.Take the magneto,and coil off a known running bike/motor and put it on this one,,if its sparks/starts then just rule out what component it was that caused the issue,,there are only a hand full of parts for igniting these things.

If your not getting spark on the plug you need to fix that first or it wont fire,,after you get spark worry about the fuel,,as long as you have a good flow from line and jet is clear the fuel should not be a problem.Also check and make sure none of the wire's are broken in the middle,, I've seen this before,,check each wire from front to back for good continuity.Also make sure that before you thread the plug cap into the new piece of wire you see plenty of copper wire at the end so there is a good connection,,you may have to cut it back a little.

If you have a old spark plug and some alligator clips you can make a spark plug tester that works much better and easier then trying to spin the motor and grounding the plug.

http://motorbicycling.com/showthread.php?t=207

Many times I have thought i had no spark when i just was not making a good enough ground.

Dave31 said:

If you have a old spark plug and some alligator clips you can make a spark plug tester that works much better and easier then trying to spin the motor and grounding the plug.

http://motorbicycling.com/showthread.php?t=207

Many times I have thought i had no spark when i just was not making a good enough ground.

Click to expand...

Thats really cool,,
I will make one on the next rainy day

Motorbikenewb said:

I have a theory that I will test when I have some time with weekend. I'm using a spring loaded tensioner on this bike and I've noticed that when I popped the clutch to try to get it started, the chain gets very tight, and I"ve noticed a lot of kinetic energy is being lost in the spring when the clutch is engaged; i.e the spring stretches. I'm guessing if I use the stock tensioner that energy will go back into the momentum I need to get the engine going. Its a long shot, but it just might work.

There are no hill for me to coast down, so I'm also considering having my daughter tow me behind her car with me tethered to a rope. Just coasting in drive, @ 10 mph. do that long enough and it won't start then I know it not for pedaling hard enough

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I don't know brother,,
Sounds like alot of messin around to me,,just give it a good swift kick with the plug out and you'll see if its sparking first,,no sense in doing all that towing non sense if you have another issue like no spark or fuel,,gotta fix that first bro..

Good times...

Tom

Motorbikenewb said:

UPDATE: Success... my theory was correct. I'm able to consistently get it started but it won't idle (pulling clutch in kills engine), and its not responding to the accelerator. And on the third try, the master link on the chain failed. So I'll reinstall the master link, prime the carb with a few sprays of gas, and also lube the accelerator cable with WD-40, and try again. Will keep you posted

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Make sure the slide in the carb is going up and down,,I had one that was a tight fit and had to polish it down a little so it would not get hung up,,also make sure the open end on the master link clip is facing toward the back axel when on the top run,,this helps the clip to stay put under engine torque.

Did you clean out the gas tank before you installed it? There's usually a lot of stuff in there that will clog up your fuel filter and carb jets. I recommend running an inline fuel filter and removing the filter in the fuel valve, specially if you have a CNS carb. The CNS has 3 jets, the main jet, the idle jet and the enrichment jet (choke), the idle jet is VERY small and clogs easily, starting and low speed riding will be very rough if your idle jet is clogged.
If you didn't start with a clean gas tank I would drain the tank and remove the filter from the fuel valve, run fuel through the tank a few times to let some of that debris flow out and then install an inline fuel filter (and leave the one in the fuel valve off). I would pull the carb and clean her out paying close attention to the idle jet (that is down that tube next to the main jet). Once upon a time my idle jet got clogged, made the motor start very rough and run rough at low speed. I pulled and cleaned the carb with carb cleaner spray, same deal. So I pulled the carb again and noticed I couldn't see a spec of daylight through the idle jet, so I reamed the idle jet with a tiny wire (from the inside of a garbage bag twist tie). This time she started right up and ran like a champ.....
Also, the CNS carb seems to be pretty sensitive to the float adjustment. AFTER you have run through 2 gallons of break in fuel and are running a standard mix if your motor isn't running great then you might need to tune the carb a bit, I would start with a float adjustment on the CNS carb.....

PS with my cns carb I only need the "choke" (aka enrichment jet) for a very brief period during startup, if I leave the choke on longer the motor will die. A pump or two during startup is all I need and she is up and running. Since it was a PITA turning the cheapo handlebar lever on and off while riding (so she didn't die at the first stop) I moved the "choke" cable over to the shifter lever on a mountain bike style brake handle. This way I can just push the shift lever in with my thumb while riding (but not enough for it to latch), when I let go it snaps back closed. This way I can richen the mix for however long I need with my thumb while riding. I really like this setup a lot. It also helps you diagnose how your motor is running, since it will add extra fuel and richen the mix on demand you can kinda tell if the motor is running rich or lean depending on how it reacts to the enrichment jet while riding.