no power in mid range !?! help

[Klausen]

from start to finish

2 month ago a bought a used 10month old good used bike EC 300 Nambotin 2009 60h or 2000km or 1400miles .

The test drive was OK but I can't wide open because the piston was new.
I believe the mid range feels normal.

Before I ride I wan't to check everything that can stop me in a race.

I checked the piston myself because trust is good but checking is better.
I release the complete cylinder - yes the piston was brand new.
I can't see any damages in the nicasil cylinder surface.
I hope I rebuilt everything right.
From the beginning there are some leaking - first I checked the float - I adjust it but leaking go on.
Then I found dirt in the tank and the carb - I clean it and install a petrol filter. No more leaking after this.
Then I checked the V-Force reed valve (2 reeds was frazzle) and I replace with 2 good used as a precaution.
I replace the plug BR8EG and the spark plug cap NGK LB5EMH.

My jettings are:

main:182
idle: 42
idle screw: 1 1/2
needle N1EF #1 from top
Temp: 5-12°C or 41-53°F
altitude: 120m
original pipe and turbinecore silencer

Today I test the machine the first time on a wider area.
The piston is 1/2h old.

In low range the torque is good and the engine feels OK but when I wan't to accelerate the engine needs a minute of silence and then he comes explosive.
Wide open is also OK.
But in the mide range this isn't a good feeling.

The new plug was often very wet!!!
My be a problem with the exhaust valve or a too low float?
I don't see a air leak.

Where can I looked for the problem?

[GMP]

Remove the right hand PV cover and observe the PV operation with RPM. My bet is its a sticky PV.

[kendunn]

first thing I would do is get a new plug and get in an open area and run it in the midrange for as long as you can then shut the bike off and check the plug and go from there with your jetting. I think if the power valve wasn't opening your top end should suffer the worst. I bet you need to replace your needle with a bit leaner one, that seems to be an issue with a lot of these bikes. Do a quick search and you can find a lot on the needles that work best.

[GMP]

If its blubbering yes, but if its a bog then check the PV. Reason is also because he had the cyl off, so an assembly problem is always a possibility.

[Gasgasogeros]

the needle N1EF is the problem for low end horsepower take a jdjetting for find the instant trothle response

[Fred1956]

Originally Posted by GMP

If its blubbering yes, but if its a bog then check the PV. Reason is also because he had the cyl off, so an assembly problem is always a possibility.

ahhh Yes !

[Klausen]

Today I ask a GG dealer.
The PV and carb and plug and s.o. work very well.
You don't believe what the problem is, it is very strange and appears only in Germany.