Misfire 2003 300 ec
 

Hi everyone,
I'm new to the forum and just getting back into biking after a 10 year break. I have just bought a 2003 300 ec. The bike has an annoying misfire in the mid range that it struggles to pull through. I have changed the plug, re packed the can and the power valve looks to be operating correctly. I ran it onto reserve the other day and when I re started it, it seemed to run great for about 15-20 seconds then the misfire returned. The carb has a 172 main, 40 pilot, N1EF needle on the second highest notch and the air screw is 3/4 of a turn out. It starts and idles no problem but always seems smokey even when warm (i'm mixing 40-1). current temp is 46f and altitude is around 1500 ft. I'm thinking maybe a N1EG needle would be a good starting point? Any advice greatly appriciated!
Thanks and great forum by the way.

Throw a N3EG in it with a 42 and a 175/178 it?ll be much smoother, cleaner and more powerful up top.
The n1ef needles are absolutely terrible. Start there and see how you go. Also make sure the float height is set correctly too.

OK thanks. I think the float height is correct, with the carb up side down and the bowl removed the distance from the gasket face and the bottom of the float is 16-17mm. I have ordered a N3EG and some jets to play about with so will give it a go as soon as they arrive. The way the bike's set up now it pulls really well from idle up to the point it starts to splutter (maybe about 5-6000rpm) but then if you can get through to the top end its pretty flat, I guess with the N3EG some of the low down power will be lost?

Nope it?ll just clean it up and make the transition nice and linear. Only a few things went wrong with mine (04) in the 20,000k I put on it. Muffler core broke at the bend and caused similar symptoms, and the little stud on the power valve arm snaps off and causes now power up top.

That's great. exactly what I was hoping to here!
Will report back when they arrive and are fitted.