Keihin Carb set up?

[JAD]

Hi all, this is my first post (after much reading!) ref jetting my new (to me) 2007 EC250.

The bike "peed" out fuel so I have removed the Keihin carb (screw top so I think it is an AS1) and meticulously cleaned everything and set the float height as per the instructions on here. Throttle cable is set correctly. Air filter is clean with fresh oil and mechanically the bike seems sound. The fuel no longer leaks and the bike starts well but has an unreliable and erratic idle which I am unable to stabilise using the techniques listed on here. The air screw (pilot?) is 1 turn out (360 degrees) and the idle screw is nearly all the way in. It will idle fast ish.. but dies after a short while. The plastic idle screw is super sensitive to even a tiny movement.


The current set up is 172, 35 with a N1EF needle in position 2 (*7 slide)

Having studied the jetting database it appears that in the UK (sea level up to 2000 ft) most people seem to fit 180, 45, and an LTR needle. I intend to do the same but I am struggling to find an "LTR" needle for sale.

Can anyone point me in the direction of a UK jet needle supplier please? (and what to ask for!)

Also, the jets appear to be available on amazon for very little money... are they likely to be low quality or does it matter? (I was thinking about buying a selection)

Thanks in advance and no doubt I will have many more questions as I attempt to get this bike sorted out!

Regards
John

[swazi_matt]

this is where the LTR needles originated https://www.lt-racing.com/ but not sure if you will find one. best is to find a ktm N3eh (or similar N3** needle) or for a more trils like feel the suzuki NEDJ (or similar NE** needle) The N1 was probably put in the GG bikes by a disgruntled employee with shares in ktm

[JAD]

Thanks Matt, the N3EH needle does seem to be available so I shall give it a try.

[frankinberg]

Ltr needle is a ddk

[SS109]

Do NOT buy jets off of Ebay. A lot are pure counterfeit, or even just cheap copies, but with their numbering system not meaning squat compared with real Keihin jets. Only buy genuine Keihin jets from a reputable shop like Jets-R-Us or the like.

If you have your idle speed screw turned almost all the way in then you are not idling on the idle circuit alone (main/needle is coming in to play which is not good). I would start with a pilot similar to what others have used for your elevation, adjust to see if it is correct for your setup (1 to 2 turns out on the air screw range, and get that sorted before even attempting messing with the needle or main jet. Everything starts with the pilot jet!

[gascadia]

My 200 runs excellent and idles all day with a 42 pilot, 175 main and CEK needle at clip position #3. Air mixture screw 1-1.25 turns. It does have the RB divider plate and circuit mods, so this may affect the pilot selection. This setup has worked well for me from sea level to 2000 feet, rain or shine, without any adjustment.

[JAD]

Just a quick note which may be helpful.. I was searching for a new air adjusting screw and discovered that it should have a washer and an O ring. Mine has neither (I looked down the hole) so this may be part of my idle problem.

Sent from my LLD-L31 using Tapatalk

[BrandonEc300]

JAD, I went out and took a look at both my keihins and neither has an oring or washer on the idle screw. I have the original black plastic idle adjustment screws also.+1 with swazi Matt about the float height?these keihins are very picky when It comes to float height. Check your reeds also, it?s impossible to jet around worn reeds and if that?s all good check the needle seat, dirty air filter causes grit to wallow out the seat creating a rich mixture. Also did you replace your slide with a genuine keihin? Aftermarket jets/slides can be much different than oem specs.

[JAD]

Yes, I was surprised about the washer and O ring but I checked and they are selling it for a PWK 38 (and others) so who knows?

I did spend some time yesterday and accurately marked 16mm on the carb and lined up the float at 60 degrees and it seems to start, idle and run much better. Note: I refitted the original Keihin slide at the same time and it is obviously much better quality than the (must be a Chinese copy) new one.

Reeds wise, I removed them and to me they looked perfect. Good clean edges and no obvious wear... having said that, this is the first time I have ever seen a "reed"!

I have just found a suitable O ring and fitted it. I have to say it has helped steady the tickover and I left it at idle for a good 10 mins with no issue so seems to help.

Also, I have had a ride on a bit of rough ground (out back) and it feels good. The exhaust has a nice "crackle" (although that may be bad!) It pulls well from low revs and has a real kick when opened up a bit. Good solid idle and starts easy hot or cold.

Subject to a road test, I think it is pretty good and certainly nice to ride.


PS.. Is it me or is this bike incredibly well balanced/stable at low speed? I have a trials bike and it feels as good as that... very impressed with its balance...

[swazi_matt]

as this is most likely in contact with fuel I would suggest using a nitrile or viton o-ring. I think the normal rubber ones may end up disintegrating (not sure where the disintegrated portions would go)