All 2st About the Mikuni/Keihin swap:

Just thought I'd throw this out here and see if it sticks anywhere:
I did the Keihin swap on my WR250 and have been plagued with a burble or sputter coming off the idle jet and into the needle. I have tried numerous needle/ jet combos ending up with a CEL 38, which is leaner than what everyone is using (that I've read about), especially when you consider the 300' elevation I'm at. It gets better the leaner I go but I can't help but think there is something is wrong here besides jetting.
Could the carb itself be at fault? It is almost like the choke is leaking, but it appears to be ok, plunger seems to go down to seat. Duno?

Oh and I have lowered the float level just a little. It is interesting that right after the tang on the float touches the needle plunger, the floats are up against the carb housing so the plunger can't be depressed very far.

What number slide?

Slide is a 7

As I have posted, I used the CEL with great results. I took the bike out to Bellingham for my Nephew and was worried that it would be too lean at that elevation. Went for a spin to check and adjust and amazingly the jetting was flawless. It might have been a tick lean on top but the bottom and mid were perfect. I just think the PWK does a great job on the bottom and mid circuits. I have yet to make a jetting change on the pwk's due to elevation differences with extended riding from 2500' to 10000'.

Walt

I have tried to follow your posts with great interest wallybean. That is why this is so frustrating.
I replated the cylinder partly thinking the low compression was part of the problem.
My powervalve seemed to be adjusted as it should be. I wish I had another carb body to try.

I initially bought a pair of CEK's and CEL's. There were a number of guys that had the CEK's and really liked them so I figured I would try them and one step leaner on the idle side just to be sure I had that covered with the auto clutch. The carb on my WR250 was pristine with very little time on it. I just think that once you set the PWK airstriker for your engines needs it will work almost anywhere with those settings. I have theories why this is true but it is all just chatter.

Walt

I do have a Rekluse. Do you think that it may have some special needs?
Steve

Steve,

I had the rekluse pro in my WR 250. I checked it several times and it was always within their specs. Seemed a very bullet proof setup. I had a complete set of spare fiber discs thinking it would accelerate wear but never saw that.

Walt

"try them and one step leaner on the idle side just to be sure I had that covered with the auto clutch."

Walt, the reason I asked is I had gotten the idea from your previous post that you chose a leaner needle (CEL) because of the rekluse. I must have misunderstood.
Steve

Steve,

You are right. I wanted the needle a little leaner at the idle end to make sure I could get it to idle at altitude. This way I have a little better control of the idle and just off idle with the pilot and airspeed screw. The results were exactly what I wanted. What I didn't expect was that the CEL would work so well at all altitudes not just higher.

Walt

Need some help please

Recently did the swap to PWK (from Motosportz) on my '09WR125 and have been trying to get it dialed in. It has the slight bog (sometimes) that may need the powervalve spring swap but it also is not running cleanly on top (on top, the Mikuni ran clean and pulled much better). It has had the powervalve upgrade and I've moved the "arm" all the way up. I've tried going richer and leaner: Richer the bog gets worse but it still won't run clean on top. I'm currently at the leanest set-up where it runs it's best: 175 main, blue needle 2nd pos, pilot 42, airscrew 2 turns out. Elevation 1000ft, temps 70-80. I don't want to return the carb until I've tried everything-before I put the PWK on, I looked at the float setting and it looked good-could it be the float or am I outta options??

I noticed the same thing and lowered my float from .630 stock to .680".

I haven't tried moving the arm down at all, when the mikuni was installed the arm was about 1/8-1/4 inch from the top. If ya think it's worth a shot I'll try moving it down 1/8 of an inch or should I go a little more at a time?

Not exactly the same, but I've been chasing the jetting for my PWK on my '09 WR125. Part of the problem is the tremendous fluctuation in temps we've had this Spring... 85F one day and 40F the next.

I ride at 1000'-2000', so I started with Kelly's jetting... 178 main, Blue needle 3rd position, 45 pilot, air screw 1.5. We have different pipes and silencers..... Kelly-Doma/PC SA, Norman-stock/stock WR Euro3 no SA.

In the jetting database Kelly said this worked 55-65F which are the temps I'd expect this time of year. Of course first ride it's 85F! The bike doesn't want to pull onto the pipe very well. but isn't too bad everywhere else. My buddy and I agree, that I should drop the needle to 2nd position and I do it after the ride.

Next time I ride, it's 40F and bike is very lean. After a few rides at 45F-55F and trying to play with the air screw, I put the needle back to 3rd position. I ride it in warmer temps and play with the air screw and it works okay, but not great. Today I rode it at 45F with the listed jetting, air screw 1.5 and it ran like a raped ape everywhere. I was pulling big hills a gear higher than before. No problem pulling onto the pipe, no bog or hesitation anywhere. My conclusion.... I need to lean out my baseline jetting across the board, at temps much higher than 55F.

I was thinking of going to 42 pilot, 175 main, red needle 3rd position, air screw 1.5. Any thoughts?

Looks like I'm gonna try the red needle, 3rd pos and see how it goes. With my latest jetting post I know when I went to the 1st pos on the needle it was too lean and ran bad so the 2nd pos is the leanest pos where it would pull from idle to the top where it still kinda flutters/misses (just doesn't pull clean and strong on top). It's gonna get up to near 90 degrees today-maybe I need to go leaner on the main yet!

In the right direction

I think ya'll got me in the right direction. With temps around 73 degrees this morning I jumped on switching to the red needle, 3rd pos and it ran great just around the shop and gravel road! I think the slight bog may be gone too!? I'll be riding this weekend and temps will be in the 80's so I'll get a better idea. Jetting right now: 175 main, 42 pilot, red needle 3rd pos, AS 2 turns out. Cool! Nothing like a finely tuned WR125!