2003 EC250 jetting changes- effect of slides

[SideshowBob]

So, see my new to me gas gas thread here.

In the process of stripping the bike down and putting all back together I observed the following-

Jetting was-
Slide #6
48 idle/pilot
Unknown needle (LTR?) see below in highest (leanest) slot
180 main

Bike had Messico Pipe with No PV cover mods. Some aftermarket reed it appears. Otherwise mods unknown. Didn't get a chance to ride it this way.


My jetting I liked in my MC250 and plan on trying out on the EC250 was/is-
Slide #7
42 idle/pilot
DDK needle middle slot
180 main

Bike has Messico Pipe with bigger PV cover mods. Some aftermarket reed it appears. Otherwise mods unknown. Will ride in next few days.


What is the effect of the #6 slide? Should I consider trying it out? Should I be worried about going from 48 to 42?

 

[jostby]

personally I wouldn't change any of the jetting, slide, or needle until I tried it out first. It might run fantastic with that setup. My XC250 runs great with #7 slide, 180 main, 48 pilot and LTR needle but if you look at what everybody else is running it isn't even close.

All this is simple to change. If you don't try it out before you make so many changes won't you always wonder how it would have performed? Same for the flywheel weight.

 

[SideshowBob]

personally I wouldn't change any of the jetting, slide, or needle until I tried it out first. It might run fantastic with that setup. My XC250 runs great with #7 slide, 180 main, 48 pilot and LTR needle but if you look at what everybody else is running it isn't even close.

All this is simple to change. If you don't try it out before you make so many changes won't you always wonder how it would have performed? Same for the flywheel weight.

That occured to me... I might switch things back to see. Since I have it setup this way I am at least going to try it.

Forgot to add pics of mystery unmarked needle..

 

[webmaster]

The mystery needle is an LTR needle - In the past, Les removed the numbers to protect it from being copied.

FYI - The jetting can vary from bike to bike as the nozzle wears - and on this bike it seems to wear quickly;

Ron at RB-Designs is the only place that I know of that can replace it for you. The nozzle is not available from Keihin and he machines one up for the application.

jeff

 

[SideshowBob]

The mystery needle is an LTR needle - In the past, Les removed the numbers to protect it from being copied.

FYI - The jetting can vary from bike to bike as the nozzle wears - and on this bike it seems to wear quickly;

Ron at RB-Designs is the only place that I know of that can replace it for you. The nozzle is not available from Keihin and he machines one up for the application.

jeff

Cool now I have every needle and then one. LTR, CCK, DDK, and stock

What does the nozzle wearing do?

I am still gonna try my jetting before I go to anything else....

So what does the slide change?

 

[jostby]

Cool now I have every needle and then one. LTR, CCK, DDK, and stock

What does the nozzle wearing do?

I am still gonna try my jetting before I go to anything else....

So what does the slide change?

I'll probably muck this up but I'll give it a shot (anyone feel free to make corrections if I do),
The needle seats in the nozzle. As the throttle opens the needle raises and the size of the nozzle combined with needle taper is what provides the progressive fuel supply. A worn nozzle will start to get egg shaped and and precise fuel delivery suffers. It makes trying to get clean jetting almost impossible.
The slide size.. I'm pretty sure I read that the number of the slide (6, 7, 8, etc) is the measurment in millimeters of the opening when the slide is fully seated. A #8 slide will allow more air flow at idle than a #6.
To get a little more convoluted I think I remember that GG modified slides at one point and made a 7.5? Can't remember if they marked them with an engraving tool or something? I think most GG 250 come with a 7 but some say the #8 works better in their conditions. Both my bikes have 7's.

Also concerning my odd jetting on my XC, I bought this bike new and it would foul plugs every ride. Les at LTR is the person that set me up with the 48 pilot. He recomended the 175 main but the 180 worked better so it wasn't a case that my carb was worn out that I went with this combination.

 

[SideshowBob]

To get a little more convoluted I think I remember that GG modified slides at one point and made a 7.5? Can't remember if they marked them with an engraving tool or something? I think most GG 250 come with a 7 but some say the #8 works better in their conditions. Both my bikes have 7's.

Also concerning my odd jetting on my XC, I bought this bike new and it would foul plugs every ride. Les at LTR is the person that set me up with the 48 pilot. He recomended the 175 main but the 180 worked better so it wasn't a case that my carb was worn out that I went with this combination.

So really a #6 slide with a 48 is a pretty rich setup?

 

[Eric K]

What does the nozzle wearing do?

So what does the slide change?

A worn nozzle will richen up primarily the 0 to 1/4 throttle range, with diminishing effect up to about 1/2 throttle. The needles wear also, having a similar effect.

As you go to higher number slide it effectively leans out primarily the 0 to 1/4 throttle range, with diminishing effect up to 1/2 throttle.

 

[SideshowBob]

So, see my new to me gas gas thread here.

My jetting I liked in my MC250 and plan on trying out on the EC250 was/is-
Slide #7
42 idle/pilot
DDK needle middle slot
180 main

Bike has Messico Pipe with bigger PV cover. Some aftermarket reed it appears. Otherwise mods unknown.

This setup worked ok. However it felt ugly in the middle and wasn't clean.

Raised the float to 18mm (thought that might be part of the problem) and then raised the clip on the DDK (lowering the needle one slot). Bike rips.

Final-
65 degrees and a little humid
Slide #7
42 idle/pilot (2.5 ish turns out on air screw)
DDK needle top middle slot
180 main


PS- as far as I can tell there is no difference between the DDK and the LTR needle. Les told me they were the same on the phone, so I looked at them together today real close like. Four people I actually had look at it, nobody could tell them apart.

 

[SideshowBob]

Final-
65 degrees and a little humid
Slide #7
42 idle/pilot (2.5 ish turns out on air screw)
DDK needle top middle slot
180 main

So I was never totally happy after 2 rides on the above setup. Made some changes yesterday, felt good at 50 deg, might need to go back to 45 for real warmth....

50 degrees and clear
Slide #7
48 idle/pilot (2 turns out on air screw)
DDK needle top middle slot
180 main