2001 EC 300 Mid Range Problems

[Jamie195]

Hello,

Recently purchased a GG EC 300. The bike starts easy and idles fine etc. However it has a huge flat spot mid range where it stutters and doesn't feel like it wants to even go through the power band in lower gears. Once past it gets better. It had BR8EG (Very black and wet) so I have changed to BR10EIX as was recommended by the local motocross shop. Carb has been cleaned and has slide #7 and needle on leanest setting. Main Jet is 178 and pilot jet is 38, I live in the UK so elevation is 0-500ft. Reeds look fine and powevalve looks fine. This is my first enduro and 2 stroke so would really appreciate some help and advice, even someone can tell me what size jets to try etc

Thanks very much

[mjtursky]

If I'm not mistaken, a BR10 is a colder plug and would foul easier then the 8. If you are running the factory JN, I would recommend the next leaner OEM JN. In most Keihin PWK carburetors, the straight diameter can influnece up to 1/4 throttle. So very little would change by moving the clip position. That would influence 1/4~3/4 opening.

[Jamie195]

Originally Posted by mjtursky

If I'm not mistaken, a BR10 is a colder plug and would foul easier then the 8. If you are running the factory JN, I would recommend the next leaner OEM JN. In most Keihin PWK carburetors, the straight diameter can influnece up to 1/4 throttle. So very little would change by moving the clip position. That would influence 1/4~3/4 opening.

Thanks for the reply... Stuck with the BR8 and I'm just going to try a 172 main jet and leave the pilot jet as a 38. Or do you have any more advice?

Cheers

[Jamie195]

Also does anyone reccomend the RM250 NEDJ needle, I imagine I can try this with my current jetting as its a leaner needle? Although I've only seen people on the forum using this needle on much newer bikes.

(Not familiar with jetting etc)

Cheers

[Jakobi]

An older model won't like a diameter that lean.

[wrench]

Are you getting a lot of smoke from the exhaust when the power drops off?

[Jamie195]

Originally Posted by Jakobi

An older model won't like a diameter that lean.

Ok is there any you would reccomend? Or would you downjet first

[Jamie195]

Originally Posted by wrench

Are you getting a lot of smoke from the exhaust when the power drops off?

Not really, it just stutters but once it's through to the powerband she's fine

[Jakobi]

What needle is in it? What state is the engine? Reeds? Exhaust packing? Are you certain its a jetting issue? You really need to know the state of the engine is good before you try to jet it up or you'll just go around in circles. The older the bike, the more important.

[Jamie195]

Ill find out what needle at the weekend but I'm certain it's a standard needle, the engine seems fine although I'm no mechanic. Checked the reeds and powervalve all seems fine. I know what you mean about jetting around the problem but I'm not sure what else the problem could be.

Cheers