Need some help from the jetting gurus

[MattR]

Background Info:
I'm tweaking my jetting on my '07 EC250 for cold weather riding (20 to 30 degF). Since this is only my second ride on a "new-to-me" bike, I don't have any warm weather experience to compare it with.

The previous owner had the following jetting. This is what he ran in the warm weather.
Main = 172
Pilot = 45
Needle = LTR
Needle position = #2
Airscrew = 1 1/2 turns out
Slide = 6.5

For my ride last weekend when the temperature was 30 degF, here is what I had installed:
Main = 180
Pilot = 45
Needle position = #3
Airscrew = 1 turn out (initially), but changed this to 1 1/2 turns out.
Needle and Slide = same as before.

Ride characteristics:
It felt a bit rich off idle to 1/4 turn throttle, so I turned the airscrew out to 1 1/2 turns (too lean it up slightly). This felt like it cleaned up the bottom.

Around 1/2 throttle, it seemed to sputter like it was running too rich. Then, it would rev out fine from 3/4 to full throttle (so I think my main jet is fine).

Here's my question:
Is this sputter at 1/2 throttle a rich condition like I think it is???

Correct me if I'm wrong here, but I think changing the needle clip to the #2 notch would help. My thought is if it is running rich, then the #2 notch will dropped the needle and make it more lean.

What do you guys think???

[Loosenut]

That 6.5 slide is killing you if you have the stock EC head.

[gasser]

Why is a 6.5 slide bad?

[GMP]

Matt,

#6.5 slide? Thats a new one. Loosenut is right. Its eaiser to dial in with the #7. My '03 had a #6 and while I got it pretty good with the RBD head, it was not as good as what the '07 is with the stock head. I rejetted it with a #7 for the new owner. The #6.5 will primarily offset the needle dia., making the off idle to mid richer with the same needle. Try dropping the neeedle, just be careful it doesn't get too lean. Work with the map switch in "sun" mode where the timing is more aggressive.

That original jetting seems very lean on the main, I never ran less than a 178 main on any of my 250s, even in summer @ 1000'.

Float height and reeds are good I assume.

[MattR]

Originally Posted by GMP

#6.5 slide? Thats a new one.

I'm assuming that I interrupted the # correctly. The slide had "65" stamped in it by the keihin logo. I took this as being a #6.5 slide. Are there half # slides or is this a #7 slide?

As you can tell, I'm still learning about jetting.

[GMP]

They do indeed exist, just never heard of one on a GG.

Sent you an email.

[Cruiser]

If youu search on the ktm talk site there are good instructions on how to cut a slide from 6 to 7. I did mine and it made a world of difference.
Steve

[RBD]

OK kids, here's something for all of you to think about (and you thought you were confused before).

The Keihin slides are as follows;

A slide that has for example a number 7 stamped on it, is actually a 7.5 mm cut-away. Most people do not realize this...., so the number on the slide is not the actual cut-away. It is always .5 mm to .6 mm more that what the number is.

Confused yet? Don't let this bother you, if you are changing slide cut-away just use the stamped number as your reference.

Ron

Ps. I can cut slides to a leaner size.