Bike fires but wont stay started

Mar 16, 2016
118
0
16
america
Everything was running fine and then this problem started. The bike will fire a few times and sometimes and can even get it to rev but as soon as i let the throttle go it dies. I've tried everything at this point. There's spark, fuel, no leaks. When testing the spark plug against the head no there would be no spark if i turned it slower but with a decent kick there was a strong spark. I don't know if this is normal i've never payed that much attention to how fast it needs to spin before spark is made.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
155
63
USA
sounds like choke came loose and is staying on, but could also be main jet fell out
 

Slogger

Member
Sep 8, 2014
545
4
18
nohio
Check your head nuts, then go right back to the carb.
These things are almost always needing dirt cleaned out of a jet or a float needle's seat.
Too much gas will do just like you describe. It could be flooding. Was the plug wet?
Mine was running ok, I cleaned the carb for spring and it ran twice as good and started a lot easier. If I had to fix it quick, I'd clean the carb especially the fuel passages.
Good luck to ya!
 
Mar 16, 2016
118
0
16
america
Head is fine torqued down properly. I took the carb apart and it was spotless. The plug wasn't wet but it was pretty dark. I assum this is from all the failed starts though. Every 50 tries or so I take the plug out and air the cylinder out to make sure there's not un-burned gas sitting in there. I mentioned in the original post that I don't get spark unless I kick it pretty hard and get it turning a few times. Is that normal? I've never really payed attention to how fast it has to spin before spark starts occurring.
 

Slogger

Member
Sep 8, 2014
545
4
18
nohio
It should make a spark at walking speed. I hold it against the head and walk the bike forward and see it.
Double check how your spark wire is clipped to the plug. My original end never would snap down right and was bent up. It can touch the plug but never runs right unless you hear the click of it going correctly into place. This gave me hours of trouble to figure out one time.
 
Mar 16, 2016
118
0
16
america
I've got a shift kit so i have to turn the pedals to turn the engine over but walking speed sounds about right. I'll double check the wiring and test the connections.
 
Mar 16, 2016
118
0
16
america
It is firing though so fuel is getting burned up. Basically i crnk on the pedals hard it sputters once or twice and then nothing. Most of the time there's no sputtering but enough that fuel would get burned I'd think. I took the carb apart and nothing was blocked or gooked up or anything. Fuel flows nicely out of the hose so there's no blockage in the tank. All needles and jets are in the right place. The spark connection is good and I'm testing with the kill switch unplugged. I really don't know what else to check at this point.
 

Chaz

Well-Known Member
Jun 3, 2012
1,004
69
48
Vancouver, British Columbia
Are you getting fuel flowing with the carb bowl drain test?

If you've had the carb apart it may be the float tang is upside down.

Are you using the stock acorn head nuts?

You may be getting a bit of fuel to fire a couple of times but not enough to keep it going. Like crassius said, if your plug is not wet after all the cranking it may be a fuel flow problem.
 
Mar 16, 2016
118
0
16
america
Is the carb bowl drain test taking the screw out of the bowl and seeing if fuel flows? Ill check the tang but I just took it apart and this has been happening for awhile. I'm using normal lock nuts not the acorn nuts. Low fuel matches the symptoms I agree but I can't find anywhere that could be causing that.
 

Chaz

Well-Known Member
Jun 3, 2012
1,004
69
48
Vancouver, British Columbia
Okay. Tang is good.

Yes, that is the bowl drain test.

Maybe raise the float a touch?

These little beggars are fun when they run but boy, they can be irritating at times. Even more annoying when you find out it is a simple little thing that's holding you back.

good luck