Pilot fuel jet and needle clip question

[onspeed]

First, my pilot fuel jets are marked 40 whereas I think stock size is like 37.5? Any reason why the PO would have put a larger one in and should I bother going back to stock or can I just screw in my A/F screws a bit to compensate?

Secondly, how much of a difference does half a clip on a needles? I'm currently on S7 needles, 2.5 clips from the blunt end, and I think I need to go a little leaner as when doing that 4k RPM cruise to WOT, I get a bit of hesitation. It's not extremely noticeable, so I'm thinking adjusting to 2 clip might fix it...

Bike has Kerker 4-2-1, DJ S7 pods, stock PAJ1 and PAJ2, and DJ 170 mains. Wideband coming soon as I'm tired of this trial/error seat of the pants testing.

 

[dannymax]

Stock PFJ is #37.5

 

[Rusty McNeil]

I would put the pilot fuel jet back to stock.
But in answer to your question as far as I know the PFJ kind of sets the "range of adjustability" for idle fuel so yes the needle could be screwed in to compensate. .

I've got a 1540cc and it does fine with stock 37.5"a in place.
While your in there I would go to a main that is Mikuni 150-147.5 or equivalent. You'll notice more power I almost will promise.
I've never done the half step thing on needles so do not know.

I love my DynoJet Wideband Commander with permanent analog gauge. It's a godsend for at least being able to diagnose symptoms as rich or lean problems without all the guessing.

 

[grimmie]

I have the Kerker header with the Morley kit. With the S7 needles I had to run the #40 pilot jets to get rid of my lean problem in the 3600 rpm range. Like if I'm running 25 mph in second gear or 35 mph in 3rd gear I would get the constant lean pop, which drove me nutz... The 40's took care of that for the most part.

 

[onspeed]

I would put the pilot fuel jet back to stock.
But in answer to your question as far as I know the PFJ kind of sets the "range of adjustability" for idle fuel so yes the needle could be screwed in to compensate. .

I've got a 1540cc and it does fine with stock 37.5"a in place.
While your in there I would go to a main that is Mikuni 150-147.5 or equivalent. You'll notice more power I almost will promise.
I've never done the half step thing on needles so do not know.

I love my DynoJet Wideband Commander with permanent analog gauge. It's a godsend for at least being able to diagnose symptoms as rich or lean problems without all the guessing.

I actually was running MK 150s, swapped them out yesterday for the DJ 170s as I was feeling the top end was a little weak. To be honest, not sure the 170s helped much. Maybe I'll try DJ 165s next until I get a WBO2 hooked up.

I have the Kerker header with the Morley kit. With the S7 needles I had to run the #40 pilot jets to get rid of my lean problem in the 3600 rpm range. Like if I'm running 25 mph in second gear or 35 mph in 3rd gear I would get the constant lean pop, which drove me nutz... The 40's took care of that for the most part.

Good to know. On the stickied thread you posted you were running MK160 main jets? Is that still the case?

 

[grimmie]

I actually was running MK 150s, swapped them out yesterday for the DJ 170s as I was feeling the top end was a little weak. To be honest, not sure the 170s helped much. Maybe I'll try DJ 165s next until I get a WBO2 hooked up.



Good to know. On the stickied thread you posted you were running MK160 main jets? Is that still the case?

Yes

 

[tugla]

try a dj 160 also.... you might like it

 

[onspeed]

DJ160 is about equal to a MK150 according to the chart? I might go back to that. I changed the 170 to 165 and it feels better, but still lots of issues below 6k RPM. Have a set of 177.5 PAJ2 on the way to me, going to try that and play with needle settings some more. If I can sort it out with 165 mains I'll stay otherwise back to the MK150/DJ160 (I have both, though I'm told mikuni has better QC on their products?). I don't understand why the DJ S7 instructions call for 175 main jets.. would be far too large for any stock displacement motor I think.

 

[tugla]

I find the dj160 slightly different then 150mik. id go to the 160dj....

 

[onspeed]

Tried out the DJ160 for a few days.... I think the DJ165 suits my bike better on top end.

Mid range WOT is still garbage... Going to check wet floats when I have a chance. Also weirdly, bike seems to pull slightly better when I'm just off-WOT versus full WOT. I think it's just the DJ160s that had this issue.