ec125 -01 power valve issue?

[Nicolas89]

Hello. new here on the forum.

I've just bought a 2001 125 ec for my girlfriend to start riding.

It runs nice at idle but very bad as soon as you open the throttle, but if i twist the throttle wide open it hits hard and revs out nicely.

My latest idea is about the power valve so i post this video to get your opinion,
is this power valve moving properly?

https://www.youtube.com/watch?v=-T-P...ature=youtu.be

thx

[savage sausage]

It's difficult to see from the video, but if it goes does not movefrom stop to stop then it might be worth taking off the exhaust, and moving it by hand whilst looking in the exhaust port.
have you got the bike jetted correctly, spark plug ok?

[Nicolas89]

What jetting and spark plug is recomended for a beginner? Fmf silencer

[savage sausage]

Originally Posted by Nicolas89

What jetting and spark plug is recomended for a beginner? Fmf silencer

I'm no jetting expert the resident jetting/carb expert is jakobi give him a shout .

firstly how does the bike start?? low range/mid range/ wot ??
take apart the carb and look at the pilot jet / main jet and needle what position is the clip at also what does it say on the needle.

are the reeds ok?

like I said jakobi is a good guy and will be able to steer you in the right direction

[Jakobi]

No first hand experience with a 125, or a GG of that vintage. Not sure the PV action looked all that good to me though. Suggestion would be disconnect the arm to the PV and make sure the valve moves as it should in the cylinder. May be a bit carboned/gummed up.

I don't like to suggest hooking into jetting as you'll waste your time if the engine isn't mechanically correct to start with.

[Nicolas89]

It starts nice. Good at idle. Have been messing with the jetting. 45. 180. N1EG in the middle #7 throttle is the current setup. The power valve parts in the cylinder moves easily. But the spring of the governor thing feels kinda stiff..

[Nicolas89]

Hard to see with it on

[Elvis74]

The max rpm on the 125 is about 10000rpm
Open the clutch housing and check the mechanic of the PV and if the steel balls are in correct position. Check also if the PV slides in the zylinder are moving smooth.

I run on mine 125 the following

Pilot jet 50-50
Main jet 185-195
Needle NOZI
Position 2
Slide no 7
Air screw 2,5 open

My PV opens at about 5000-6000 rpm and it just snaps open, no slow moving.

[Elvis74]

When the piston is in top dead center, the ignition must be located like this:



Check the gas cap too, maybe the tank vent is blocked and due to this the fuel is only able to go slowly down into the carb.

The squish should be around 1,4mm when using all original parts.

[Nicolas89]

I've now checked the float level, it was 16 mm.

I ran it without the fuel cap a few days ago, no difference.

The idea of measuring the piston, rings and cylinder is of course not a stupid idea but is it really believeable that it will run bad only in the mid range due to lack of compression?