best pwk needle jets

[rtcc]

While I am thinking about these carbs I am trying to find the best needle for my riding style. I know longer slow taper needles give you more of a smooth power transition throughout the throttle range.

I like to have lots of bottom and mid range power. I feel pretty good now but I could be missing a lot with the needles I have now. They came with the carbs and have no markings at all on them.

 

What are needles do you guys recommend? Im pretty new to Keihin carbs.

 

thanks

[00tbanshee]

not sure what all you have done, but i know ported motors the CEL needle seems to be pretty popular

[ClimbAnyHill]

I like the sound of this thread, just subscribing!

[rtcc]

not sure what all you have done, but i know ported motors the CEL needle seems to be pretty popular

 

I need to put my mods in my signature.

 

anyway they arent much, I have no port work as of yet.

>Paul Turner High revs/ FMF powercore silencers

>noss head 20cc domes

>RM stator w/+4 timing

>Kehien PWK 28mm carbs

>Ported stock reed cages w/TDR reeds

 

I would love to measure my needles but what tools would I need for that?

[BellicoseBanshee]

Needles are a fuel metering device. A reasonable state of tune is going to give you the best performance, not changing the needles for more bottom end...

 

You definitely want the needles that correct any jetting issues you may be/are experiencing. If I can remember correctly, the standard needle for the 28PWK is an N68A. I know many people like the JJH needles. I don't think needles other than the ones that deliver proper jetting is going to give a performance gain.

[rtcc]

Right, Im not exactly looking for a needle that will give me more power. I just want to make sure I am running a needle that gives me the best throttle curve for my riding style. And since I have no idea what needles I have, I dont even know where to begin looking. Im also wondering if the needle has anything to do with my fouling problems on the bottom end.

[rtcc]

Ok I am going to bring this back.

 

I have everything dialed in better now but I have my needle on the highest notch to get rid of the gargle at 1/8th to 1/2 throttle.

It feels though that this is leaning out my 1/2 throttle and up too much.

Again, I have no idea what needles they are because there is no markings on them.

 

So Im asking at what main jet size do people feel they need to change there needles? I am running 155 mains now and they rip.

I heard that the N68A is the stock needle and that JJH needles are good. Do people upgrade to JJH's after they go higher in the mains?

 

thanks

[2strokespirit]

I have the same thing. Ok on 33mm pwks they came with C GL needles. I have a trial ported 4mm and the needle are on the 5th clip, richest, still a lean issue just above 1/2 throttle, so I am going to get CEL which are a "richer" needle..

There is a chart on the sudco website which indicates which needle are richer or leaner..

[dirtclod20]

Ok I am going to bring this back.

 

I have everything dialed in better now but I have my needle on the highest notch to get rid of the gargle at 1/8th to 1/2 throttle.

It feels though that this is leaning out my 1/2 throttle and up too much.

Again, I have no idea what needles they are because there is no markings on them.

 

So Im asking at what main jet size do people feel they need to change there needles? I am running 155 mains now and they rip.

I heard that the N68A is the stock needle and that JJH needles are good. Do people upgrade to JJH's after they go higher in the mains?

 

thanks

 

I have almost the same setup as you. 21cc domes, trail port, pro-circuits, ported reed cages w/TDR reeds, stock stator. My 28pwk's have 155mains, 45 pilot(which seems way to lean, causing me to chop the throttle constantly to keep it running) or the choke seems to make it idle perfect, but not run any better. 3turns out, JJH needle 2nd clip from the top, with dual stage uni pods. Feels lean, and the quad feels very hot, a little idle or ride feels hotter than a WOT plug check run. This doesn't seem to be the reciept of champions or the winning formula to producing smooth consistant power. Maybe 50pilots will help me and JJH needles will help you, it's not going to break the bank.

Marcus

Edited May 28, 2009 by dirtclod20

[Thewhite]

Ok I am going to bring this back.

 

I have everything dialed in better now but I have my needle on the highest notch to get rid of the gargle at 1/8th to 1/2 throttle.

It feels though that this is leaning out my 1/2 throttle and up too much.

Again, I have no idea what needles they are because there is no markings on them.

 

So Im asking at what main jet size do people feel they need to change there needles? I am running 155 mains now and they rip.

I heard that the N68A is the stock needle and that JJH needles are good. Do people upgrade to JJH's after they go higher in the mains?

 

thanks

 

 

I have some pwk 28 with a oval over bore: 28mm with and 30mm tall, I use a 50 pilot, 258 main and N68A needle. Originally I got the JJH and the bike was rich at 3/8 throttle, so I chanhe for some N68A and it help to solve the problem.

 

The Needle end is basicly the same but the beginning have a second taper. It help to have a better transition of the needle opening. I the first taper is 3 deg and the second is 1 deg (the same as the JJH). See the attachement.

 

The N68x serie needle is more populaire in europe on the high modified scooter, I got those number from hte net:

 

d1 d2 d3 d4 d5 L1 L2 L3

L4 θ1 θ2

 

N68A 2.435 2.409 2.391 2.253 1.625 27.45 28.5 31.39 43.39 1`00`` 3`00``

 

N68B 2.385 - - 2.253 1.625 - - 29.14 41.14 1`00`` 3`00``

 

N68C 2.395 - 2.391 2.253 1.625 - 26.25 29.14 41.14 1`00`` 3`00``

 

N68D 2.405 - 2.391 2.253 1.625 - 26.25 29.14 41.14 1`00`` 3`00``

 

N68E 2.415 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

 

N68F 2.425 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

 

N68G 2.435 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

 

N68A 2.435 2.409 2.391 2.253 1.625 27.45 28.5 31.39 43.39 1`00`` 3`00``

 

N68H 2.445 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

 

N68I 2.455 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

 

N68J 2.465 2.409 2.391 2.253 1.625 25.2 26.25 29.14 41.14 1`00`` 3`00``

[rtcc]

ok, so to update this thread I have now installed the JJH needles.

 

They are a very nice improvement. I have the clip on the second from the top with my 38 pilot and 155 mains.

 

The 1/2 to full throttle is a huge difference. The 1/8 to 1/2 is crisper as well.

 

The needles that I took out are unmarked but they have a longer and thinner taper and I had to have them completely leaned out for it to run decent at all.

 

So for now the JJH's are gonna stay.