Two stroke help

[SolarBell]

I need some help! My son's Kawasaki 65cc dirt bike is acting up and I can't figure it out.

When over 2/3 throttle or more, even under almost no load, it bogs, sputters, and occasionally backfires.

I'm running the same jetting as I have been for the last 3-4 months with no issues. I did a top end about 2 months (20 engine hours) ago. I'm seeing about 105 psi of compression but I haven't validated the gauge at all. I dumped the fuel tank and flushed out the dirt I found with fresh fuel. I installed a fuel filter to prevent any possible problems. I pulled the carb and main jet and hosed down all the passages with choke/carb cleaner. I replaced the spark plug. I made sure the exhaust pipe was free of blockages.

After all that it is slightly better but is still having problems. I'm at my wit's end and my son is supposed to race on Sunday. Is there anything else I should look at?

 

[rockfrog]

Have u checked the reeds?

 

[SolarBell]

Reeds are fine, no cracks or fraying.

 

[rockfrog]

are they sitting flat against the reed block? if they r a little bit bowed up you can flip them over and use them that way.

 

[SolarBell]

I eventually got it running right. I tore the carb down again and pulled apart every single component that it had, then washed it all with carb cleaner and blew it all out with compressed air.

 

[old_man]

I just saw this post. I was going to recommend tearing down the carb and cleaning out the jets. You beat me to it.

Congrats on getting it running. I would do a plug reading after running a bit to make sure that your mixture is still in range.

 

[freerider15]

Two strokes are the debbil...

I've got a tiller with one, and it's a constant fight to keep it running "good enough". This is after completely going through the carb, new spark plug, air filter, etc.

And I've also got a weed wacker that needs it...but its not high on the priority list.

But I reiterate...two strokes are the debbil...

 

[SolarBell]

Yes, they may be. But seeing a group of 7-11 year olds, some of whom are absolutely hauling ass on 65cc's of two stroke power, is pretty fun.

 

[SolarBell]

Congrats on getting it running. I would do a plug reading after running a bit to make sure that your mixture is still in range.

I'm keeping an eye on it. Anymore I can tell if it's close just by the sound and the smoke when my kid rails on it.

 

[SolarBell]

Two strokes are the debbil...

I've got a tiller with one, and it's a constant fight to keep it running "good enough". This is after completely going through the carb, new spark plug, air filter, etc.

And I've also got a weed wacker that needs it...but its not high on the priority list.

But I reiterate...two strokes are the debbil...

Oh yeah, one other thing - Two strokes that are jetted from the factory for < 1000' elevation and are essentially unchangeable are truly evil. All you can really do is mess with the oil mix ratios a little bit, but they are forever too rich.