Will not reach powerband 06`EC300

[barossi73]

Try it with the kill switch disconnected or at least removed/hanging from bars (if you havent already!)

[GGRider01]

Originally Posted by stian

Well, kinda funny, cause my KTM also started to bug couple of days ago. But if both coils have gone, thats one bit of a coincident

I am kinda sick of this.
Correct settings on the voltage meter is 2k on "ohm"? Both showed around 10.85

I used a cheap(ish) auto ranging meter, but the results it gave me were consistent and repeatable. So to be blunt, I don't know what settings you should be using on the meter. All I know is that the results you're seeing aren't the same that I get. It seems highly unlikely that you'd have two coils go bad and even less likely that they'd be returning nearly identical readings if they both went bad.

I wish I knew what to tell you

[400_racer]

Sounds like most things have been suggested and checked, the only thing i'll add is regarding the reeds.

You say in your opening post you changed 2 of the 4 petals. I recently had similar issues where it wouldnt rev out cleanly in the powerband / sputtering at higher rpm. I changed and checked a few things, but it wasnt until I changed reeds (all of them) that it went away.

Not sure why you only changed 2 (perhaps the other 2 looked ok?), but apart from a tiny little chip in the corner of one petal on mine, they all looked fine. Maybe the two you didnt change are giving you problems?

[HerminatorZA]

If your compression is low, the bike will not rev into the powerband.
Have your checked piston and rings

[stian]

Originally Posted by 400_racer

Sounds like most things have been suggested and checked, the only thing i'll add is regarding the reeds.

You say in your opening post you changed 2 of the 4 petals. I recently had similar issues where it wouldnt rev out cleanly in the powerband / sputtering at higher rpm. I changed and checked a few things, but it wasnt until I changed reeds (all of them) that it went away.

Not sure why you only changed 2 (perhaps the other 2 looked ok?), but apart from a tiny little chip in the corner of one petal on mine, they all looked fine. Maybe the two you didnt change are giving you problems?

Replaced all of the petals, but after 15h, two of the petals were shot. I replaced the two broken with the two old. The problem with bogging was before, AND after replacing reed-petals. New and old.

Regarding piston, its a 15-25h old piston, clearences are good, piston-rings are well within spec (<0,30) and the problem was also with another piston.

Going to cut open the electrical wires from stator and up, order a new coil and disconnect everything but stator, coil, regulator and CDI.
Also going to add a new sparkplug and clean the carb, for the 103th time.

Better safe then sorry.

Thanks for the answers! Ill keep you posted

[Neil E.]

The voltage regulator should have no effect on the ignition system; it only clips peak voltage for lighting.

For sparks:
1) Single exciter winding on the stator plus wires
2) Pulse trigger outside of the flywheel plus wires
3) CDI plus wires
4) Ignition coil plus wires
5) High tension lead plus spark plug
6) Grounds for the engine and coil etc.

The flywheel magnets could be weak if the flywheel has been smacked or otherwise beat up by a previous owner. Breaking up at high RPM suggests a bad wiring connection or corroded wire or shorting out due to bad insulation. There's got to be an answer somewhere.

[motopsycho87]

You said the bike runs fine for 15 minutes then bogs? Then it can only be electrical. It's a very common symptom of a failing coil somewhere or cdi,run well cold, but something expands and shorts or disconnects the circuit somewhere...

[Terrence R]

Is your gas cap vent clogged with dirt? I Had a similar problem with a bike before with this issue. Same symptoms as u described.

[stian]

Originally Posted by motopsycho87

You said the bike runs fine for 15 minutes then bogs? Then it can only be electrical. It's a very common symptom of a failing coil somewhere or cdi,run well cold, but something expands and shorts or disconnects the circuit somewhere...

Had the bike in parts, for new bearings, gaskets, sprockets, oil, etc.
after the rebuild, I fired up and took it on a 45min run. 15min out of the 45min, it started to bog as usual.

As Neil said, I am guessing its a bad connection somewhere.
Does someone have a picture of the wiring to the cdi box / ie. from the stator? As I said in page 2 here, I think previous owner had it wired wrong.

Fuel runs freely, and nothings clogged. Ive got a lot to do these times, so i am going to the shed when I got the time for it.

[Terrence R]

Originally Posted by stian

Had the bike in parts, for new bearings, gaskets, sprockets, oil, etc.
after the rebuild, I fired up and took it on a 45min run. 15min out of the 45min, it started to bog as usual.

As Neil said, I am guessing its a bad connection somewhere.
Does someone have a picture of the wiring to the cdi box / ie. from the stator? As I said in page 2 here, I think previous owner had it wired wrong.

Fuel runs freely, and nothings clogged. Ive got a lot to do these times, so i am going to the shed when I got the time for it.

Personally, I would run it with the gas cap loose just to confirm that's it's not gas vent related.