[Rick O'Shea]

Which affects the idle more the needle position or the pilot jet?

[ace.cafe]

Which affects the idle more the needle position or the pilot jet?

Pilot jet and idle bleed screw affect idle almost entirely.

[Rick O'Shea]

Pilot jet and idle bleed screw affect idle almost entirely.

This is what confuses me ACE. Mike Baird and others are sucessfully running a 25 pilot like I am at sea level to 1000' with bikes set up very similar to mine. Yet mine is evidently too LEAN at 2500', an elevation that should contribute to a RICHER mixture with the same jetting, right? I checked the float and It seems to be correctly set at 19mm, if I'm checking correctly. I thought I would work on the idle then the midrange then the main. Even though they somewat overlap in function it seems that would be the natural progression. Thanks , Joe

[ace.cafe]

Hi Joe,
I try to treat these bikes all individually. There are differences.
We just want to get what works on your bike.

Now, we've seen that with much larger jets, you get poor fuel mileage, but it runs.
Since then, you've leaned out considerably, and now it's not running so good.
That tells me you have to find a middle ground.

Yes, 2500' elevation should cause richer mixture, and expect to jet a little leaner.
However, there could be all kinds of things involved here, including your exhaust system and air filter system, and even individual characteristics of the engine internally.

So, I just do what works for the bike that I'm working on, and the others might only be a general guideline.

Also, be aware that when you get too lean, it can become very sensitive, and cough and sputter and act pretty bad. The fact that you can bottom-out the bleed screw is a clear indicator of needing the next pilot jet size.
If I was doing this, my next move would be a step richer in everything, and see how that does.

[Rick O'Shea]

Ace, thanks for all the input. I ended up with a 125 main, a 25 needle and the needle clip one position above the center slot. The mixture screw is only out 3/4 from bottomed to get optimum idle. I did find the float set at 22mm instead of 19mm so I reset it. Joe

[walken4life]

So, yesterday, there I was.  It was a beautiful day in Northwestern Pennsylvania.  I had decided to at least start the replacement of my stock carb, air filter, and exhaust by removing the old carb.  I purchased the 30mm Flatslide a few months back after all the glowing reviews here.  I have it jetted with 132 Main and 35 pilot. 

Much to my dismay I found that I had bent the needle in the process of changing the jets.  Must have happened when I pulled the float bowl to change pilots.  I bent it back as straight as I could get it, but it left me a bit worried.  Bike is still apart at the moment, and I am tempted to buy a new needle just to be sure.  The local Yamazuki shops were no help.  Tried 3 and not one of them stocks needles, only jets (??).

My question is this:  Can anyone tell me the three letter voodoo code for the Keihin PWK needle that comes with this carb?  I know there are many different ones based on where/if the needle tapers, etc., but I was at a loss to decipher this.   I appreciate any help.

[baird4444]

are you sure that 3 letter code isn't stamped on there somewhere?
You can get that needle here-
http://scootrs.com/category.cfm?category=127?CFID=571839&CFTOKEN=173EB056-9CD2-E373-ACA517CD00F6308F

there is also a chart if you can measure yours up to figure it out.
            - Mike

[baird4444]

Ace, thanks for all the input. I ended up with a 125 main, a 25 needle and the needle clip one position above the center slot. The mixture screw is only out 3/4 from bottomed to get optimum idle. I did find the float set at 22mm instead of 19mm so I reset it. Joe

    Joe-   is this your final setup??   what mileage have gotten?
                   - Mike

[walken4life]

Baird,

Thanks for the reply on the needle.  Bike is out of commission in the meantime, but at least I am not missing good riding weather in the meantime.

[Rick O'Shea]

Hey Mike, 125 main, 25 pilot, needle position 1 groove down from the top. re-set float to 19mm. Mixture screw seems to like it 1 full turn out from bottomed.Slight burble and low pop at high RPM deceleration...any thoughts on that?    Running 87 non-ethanol. Classic pipe, K&N pancake. no catchcan or PAV stuff. 19 tooth sprocket. Bike runs great; MUCH better midrange and full throttle response. Haven't checked mileage yet but will have an idea this weekend.....Keep ya posted...... thanks, Joe

[baird4444]

Hey Mike, 125 main, 25 pilot, needle position 1 groove down from the top. re-set float to 19mm. Mixture screw seems to like it 1 full turn out from bottomed.Slight burble and low pop at high RPM deceleration...any thoughts on that?   Running 87 non-ethanol. Classic pipe, K&N pancake. no catchcan or PAV stuff. 19 tooth sprocket. Bike runs great; MUCH better midrange and full throttle response. Haven't checked mileage yet but will have an idea this weekend.....Keep ya posted...... thanks, Joe

Couldn't find it in my notes but seems like someone once said that popping on roll off or decell indicates lean.....      anyone??
sounds like you are close. have you done any plug chops? Just a guess but I think I'd raise the needle 1 notch....
                    - Mike

[Rick O'Shea]

Couldn't find it in my notes but seems like someone once said that popping on roll off or decell indicates lean.....      anyone??
sounds like you are close. have you done any plug chops? Just a guess but I think I'd raise the needle 1 notch....
                    - Mike

I guess I should have said two grooves down from the top or four up from the bottom. I think it's in the same place yours is Mike. Joe

[Rick O'Shea]

   Joe-   is this your final setup??   what mileage have gotten?
                   - Mike

I've checked with two tanks since the rejetting and repositioning of the needle. Looks like I'm coming in between 60-70 MPG. Well worth the effort.

[baird4444]

well that does it...   I'm gonna have to go back to mine. Is your final needle setting your first try with the 125 or did you see some improvement by lowering it? I fell like there is more change with the settings on these than the orig. carb.
                        - Mike

[Rick O'Shea]

Mike, I started off with the needle clip in the top slot and the bike would not start, just loaded the pipe and backfired so strong it broke the baffle loose in the muffler. I moved the clip to the next slot down and it improved noticeably. It may still be slightly lean at idle because I have the mixture screw out only 1/4 to 1/2  turn from bottomed to get an optimum idle without spitting back out the carb or burbling during roll of and decel. It's running really well throughout the entire throttle range now and if i do anything else I may drop to a 120 main just to experiment and drop the clip one more notch (to the middle) just to be safe from a too lean midrange. Or hell I might just quit tweeking and RIDE the damned thing........Joe   P.S. last tank checked at 63 MPG