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EXC 125 2009 - ignition/high rpm problem

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Dear All,

My problem with pover valve is gone - 

But now I have next suprise. 

In medium-high and high rpm's engine break/interrupt a ignition, also there are some pops/shots from exhaust, please look at video:


Engine and bike is already after general repair. I got new sparkplug (according to Manual), fuel-oil ratio and all parameters according to Manual. I also already fixed problems with povervalve - I don't know nothign about stator and CDI unit. Maybe it's some problems with ignition timing? 

I would be gratefull for all issues and advices - I spend a lot of time and money for this bike, but it still don't have power according to this problem. During ride 1st to 3rd gear are almost good (but still not good as other 125 cc) 4-5 gear much weaker at high rpms, and in last 6th gear I even can't touch high rpm's.

Best regards


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Today I've removed ignition cover and marks on engine case and stator are not in one position, mark on stator should be in the same line with mark on right side (I have 2K-3):


My setting:


Here better look:


And with additonal line:


How you think, it can occurs my problem with ignition? Difference is small but I need to take of flywheel to change it.

Would be gratefull for all advices!


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Dear All,

This week I've received my ignition: flywheel, stator, CDI and coil from service - ignition works with parameters suitable to manual.

Yesterday I've rided about 15-20 mins with high rpm to check spark plug and this what I seen after dismouting spark plug:







As you can see, on ceramic isolator and electrodes I have hard carbon deposit - that means I have too rich mixture. But my carburetor is set according to manual. Spark plug also according to manual (good heat, type etc.)

Powervalve, filter, membrane, ignition are totally ok - as I wrote engine is after general repair. 

Carburetor components are fitted according to manual guide:


Main jet: 170

Idle position: 4

Idle: NOZF

Idling jet: 48

Air screw from fully open (ASO): 1 

Biggest issue with ASO - 1 full turn from fully seated give me bad acceleration and reaction for throttle. I get good result with 1,5 - 2 full turn from fully seated.

Fuel level and components of carburetor are ok - today I order new main jet and idling jet. 

Maybe you can give me some extra issues?



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Have you found the problem? I have the exact same issue on my Ktm exc 125 2007. Thanks!

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