Ec250 running issues

[jimgsxr86]

I have recently acquired a 2003 EC250. This bike starts very easily but runs badly. The engine barely picks up in the first 3 gears, refuses to run at slow speed and fouls the plug after about an hour of riding.

The current set up is:

38 Pilot
180 main
Running 40:1 mix

The bike barely ticks over with the adjuster wound all the way in and the air/mixture screw has no effect on the way it runs regardless where I turn it.

Is there a general base setting anyone can recommend for me to start with? As I don't really know where to begin. There are no air leaks and I believe the crank seals are good.

I am approx 100 metres above sea level and temp averages around 12 centigrade.

Thanks

[Brian]

IMO that pilot is too small. Try 40 or 42.

Which kind of lines up with this:

The bike barely ticks over with the adjuster wound all the way in and the air/mixture screw has no effect on the way it runs regardless where I turn it.

[Jakobi]

Originally Posted by Brian

IMO that pilot is too small. Try 40 or 42.

Which kind of lines up with this:

Without knowing the needle thats really just an educated guess, but a good one. Conversly he's describing a rich condition with fowling, and the requirement to turn the idle right in opening the slide (leaning things out) is also and indication of being too rich. The result of this is that the pilot circuit has all but been bypassed which is why the airscrew has no effect.

Now, like always with an older bike. You won't (read will never) be able to jet out a mechanical issue such as worn rings, pv issues, leaking seals (stator side/clutch side), or flogged out reed petals. Check these first.

Then while the carb is out, give it a clean, set the floats, find out whats actually in it (including the needle) and then come back with your findings and we'll have somewhere to start from.

I know it sounds like a lot of work, but thats what you need to do to get the job done right. The more info you can provide, the more detailed your responses will be.

Cheers
Jake

[jimjim]

Warped or chipped/cracked reeds.

[jimgsxr86]

thanks. I'll have a look.

[theexception_03]

I have a 2004 EC250 that had massive issues when I first got it, running rich, didn't want to idle, idle screw nearly all the way in and air screw did nothing

I re jetted it alot before I found out I needed a new CDI and stator,

now I have this set up

NEDW#2
175 main
40 pilot
air screw 2 turns out

I hope this helps and good luck

make sure PV and reeds are all good too

[TavisB]

Sounds just like what mine was doing with a bad stator.

Sent from my HTC One X using Tapatalk 2

[GMP]

That sounds lean for an older bike, whats your elevation?

[AZRickD]

That 38 pilot is something I use in Flagstaff, Arizona (elevation 7K to 9K) in the summer (85F). I use a 168 MJ there as well (with carb and head mods). I needed a 162 without the carb mod to keep it from burbling once I climbed to 9K on the trails.

I would suspect that a pilot of *at least* a 42, probably a 45. The MJ should be in the ballpark.

[GMP]

From my experience with that needle series in 250s with the old carb, the dia isn't even close for 1000'. I'm working with the F dia now.