2002 ec250sm jetting problem

[chrisboy]

Tried searching through the threads, but struugling to find what i need..

Bought this recently, and it runs, but rough enough.

Here's the jetting..

needle : NIED position 3

Pilot: 45

Main jet: 185

It starts first kick and idles well, but stutters a good bit getting to the top end and doesnt cruise well.. I also couldnt tell if the powervalve is working or not, as in there's no great pull at any stage..

I changed the needle to position 2 and this seemed to smooth it out a bit but again not sure if the powervalve is kicking in.

I've also bought a 180 main to see if this will help.

So, a couple of questions! Should i raise the needle position another notch and put the clip in position number one?

I'm also wondering is it even the right needle, and would i be better changing to a different needle?

Cheers in advance lads, haven't owned a 2 stroker in a good few years, so taking a while to get to grips with it!

[chrisboy]

Anyone? Anyone? Bueller? Beuller?

[desertgasser300]

Things like your altitude, ambient temps will play a roll in how your bike will run. Hard to say where to start without some of these.

[Jakobi]

Read the powervalve sticky to learn the system back and forwards. Its very easy to check its function on the stand. Pull the pipe off and then the RHS PV cover, put the pipe back on and run the bike on the stand. You should be able to see the PV plate rotating between the stops.

Also, being a 2002 model, whats the engine like? You won't be able to tune out a mechanical issue, so things such as reeds, ring seal, engine seals etc will all need to be confirmed in order.

With the carb, after ensuring its clean (and the engine mechanically checks out), set the float height, and then start on the low throttle openings and work your way up. If it idles well and off idle is good then the pilot and needle diameter is probably ok. If it breaks up and sputters at 1/4 throttle heavily then try lifting the clip position until it runs well up to 1/2 throttle. Then dial the main jet in.

[chrisboy]

Originally Posted by Jakobi

Read the powervalve sticky to learn the system back and forwards. Its very easy to check its function on the stand. Pull the pipe off and then the RHS PV cover, put the pipe back on and run the bike on the stand. You should be able to see the PV plate rotating between the stops.

Also, being a 2002 model, whats the engine like? You won't be able to tune out a mechanical issue, so things such as reeds, ring seal, engine seals etc will all need to be confirmed in order.

With the carb, after ensuring its clean (and the engine mechanically checks out), set the float height, and then start on the low throttle openings and work your way up. If it idles well and off idle is good then the pilot and needle diameter is probably ok. If it breaks up and sputters at 1/4 throttle heavily then try lifting the clip position until it runs well up to 1/2 throttle. Then dial the main jet in.

Thanks, The engine seems tight enough. Took it for a spin, and when you pin it, runs extremely well in certain spots on the acceleration range..

I opened up the pv cover, and there's a bit of slack in the PV plate. It moves about 5-10mm without activating anything, then it turns smoothly.

HAve you ever heard of the NIED needle? No one else on the site seems to be running one! Would it be worth while trying a more popular needle?

Thanks for the help, its much appreciated.

[Jakobi]

No worries.

I haven't heard of an NIED, but I'm assuming its probably an N1ED. The N1Ex needles have been stock in gassers for since forever. The new ones still come with an N1EF which is a couple steps leaner from 0 - 1/8thish throttle.

I have no idea what the older bikes or carbs like so making suggestions regarding needles would be just pulling at straws. Use a methodical approach and make one change at a time to determine the throttle position where the bike won't run well and then adjust accordingly. I'm guessing if you could get your hands on a JD Blue needle you might find bliss, otherwise search the jetting database here and see what others used in the early models. DDK? DEK? For $10 I'd probably try something like an N8RG Yamaha/KTM needle too.

But first step. Lift the clip up one position on the needle and ride it. It'll either be a step in the right direction, or feel really wrong.

[chrisboy]

Thanks Jakobi, you're correct on the needle, ill try raising the clip again first..

[theexception_03]

Hi

I have a 2004 EC250 and had a heap of trouble with mine when I first got it

I spent money on it trying sort it out then I started to re jet which didn't help much until I had a new CDI put in and the stator rewound

Anyway I am at this set up

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

I ride at sea level and dry conditions, the bike pulls hard in ever gear

Probably could even go to a 172 main

Other needles to try are NECW and DDK

Good luck and don't be afraid to have your electrics tested.... I wish I had mine tested first!!!

[bally123]

Hi

I run a 2005 250 EC and had similar running issues to you.

1. Check Reeds - broken tips / poor sealing
2. Stripped cleaned and Adjusted PV
3. I then replaced crank seals (optional but not that expensive to do)
4. New plug
5. Clean filter
6. Repacked exhaust and welded up crack in rear pipe
7. Replaced NE1F with DDK (clip 3) needle combined with 45 or 42 pilot

Bike has been so much better, clean running, pulls strong - Fuel economy pretty much doubled. (Note I use for mostly green lane runs so lots of low speed technical stuff between high speed road sections)

My advice is to ensure all the basic health checks are made before you play with jetting - if something fundamental is wrong you need to fix that first. When happy the basics are good then as a start the DDK works well

Hope this helps..

[chrisboy]

Originally Posted by Jakobi

No worries.

I haven't heard of an NIED, but I'm assuming its probably an N1ED. The N1Ex needles have been stock in gassers for since forever. The new ones still come with an N1EF which is a couple steps leaner from 0 - 1/8thish throttle.

I have no idea what the older bikes or carbs like so making suggestions regarding needles would be just pulling at straws. Use a methodical approach and make one change at a time to determine the throttle position where the bike won't run well and then adjust accordingly. I'm guessing if you could get your hands on a JD Blue needle you might find bliss, otherwise search the jetting database here and see what others used in the early models. DDK? DEK? For $10 I'd probably try something like an N8RG Yamaha/KTM needle too.

But first step. Lift the clip up one position on the needle and ride it. It'll either be a step in the right direction, or feel really wrong.

Thanks For all the advice lads, very informative.

anyway here's what ive done ..

1st, raised the clip one notch which seemed to make it a bit better, then after reading Jakobi's last post, decided to raise it to the top notch, which cleaned it up brilliant.

2nd, changed the main jet from a 185 to a 180 and that in turn, cleared up the top end!

3rd, changed the pilot jet from a 40 to a 38, which cleared up the lower part of the throttle.

Bike is now running exceptionally well and is a completely different beast to when i bought it! Its now absolutely savage on the road, front wheel lifting in 3rd gear, and idling perfectly hot and cold!

Thanks to all that helped me with this, i now have a great understanding to how a carb works, but also a great understanding as to how sensitive a 2 stroker is to its air/fuel mix!