Jetting Again PWK 28

[PikledBeats]

Yes I know I posted this earlier but it is so buried in the jetting section I do not think I will get any responses

So I got my hands on a new PWK 28mm Genuine Keihin Carb. I have absolutely no experience with these carbs but have been testing diffrent intake setups and was going to do a review of the PWK 28 Vs. the TM 28 with diffrent intake/reed/spacer setups. Regardless, I need a good starting point for jetting on the PWK. Yes I have searched and done some research on the site and have a good Idea of where it should be but thought I'd see what you guys think.

Mods:
CFM/UNI
Prodesign/VF3
Stock 66mm jug
Dynoport right bend

1700-2300 elevation AVG. 70 degree

Hopefully I'll get some answers that mimic what I've read so I can actually do this, I think it'll be good info for all.

My research turned up pilot between 45-50 and main between 155-165 a closer starting point would be awesome though

 

[mmajay]

152 main/45pilot should be very close .

 

[PikledBeats]

152 main/45pilot should be very close .

thank you rep givenI:I

 

[PikledBeats]

will the 152 main/45 pilot give me room to work down i.e. on the rich side to be safe ... or closer to what it should exactly be.

Is there a conversion chart somewhere for mikuni to keihin jet sizes? Edit: yes I have found many but do not understand how they list keihin as bigger than the equivalent mikuni unless their is a conversion formula that I'm missing

 

[blasterfreek30]

u could start with a 155 main and work down from there...being i think that will be a bit rich but i think the 45 pilot should almost be dead on for ya or real close

 

[PikledBeats]

Ok I ordered two jet kits, one with mains from 150-160 and then a pilot kit that has eight total with 45 being in the middle.

I should be fine, and appreciate some knowledgeable members chiming in. I am looking forward to see the diffrence between the TM28 flatslide which I have jetted exact right now for my mods and the PWK. It will make the deciding factor when I go to switch carbs for porting but should also give some good knowledge to members.

I'll be testing Carb: PWK28 VS. TM28, Prodesign billet intakes:Non-diverter and diverter models. Prodesign spacer vs. non-spacer, Reeds: VF3 with custom stuffer (similiar to cascade innovations) vs. VF3 inner cage (Ported) vs Stock/Boyeson.

I have all parts needed (minus the PWK jetting which jsut got ordered) to do this, so look forward to full write-up.

 

[slickerthanyou]

I was gonna post but i agree with the above answers u got that's what i started with in my 30mm, which is a 28 bored!

 

[Awk08]

Ok I ordered two jet kits, one with mains from 150-160 and then a pilot kit that has eight total with 45 being in the middle.

I should be fine, and appreciate some knowledgeable members chiming in. I am looking forward to see the diffrence between the TM28 flatslide which I have jetted exact right now for my mods and the PWK. It will make the deciding factor when I go to switch carbs for porting but should also give some good knowledge to members.

I'll be testing Carb: PWK28 VS. TM28, Prodesign billet intakes:Non-diverter and diverter models. Prodesign spacer vs. non-spacer, Reeds: VF3 with custom stuffer (similiar to cascade innovations) vs. VF3 inner cage (Ported) vs Stock/Boyeson.

I have all parts needed (minus the PWK jetting which jsut got ordered) to do this, so look forward to full write-up.

sounds like this is gonna be a very informative test,
too bad we couldnt get a "rad valve" thrown into the mix

 

[Larry's Shee]

I'm confused :-/ how do you figure it's 70* in Idaho? Unlessyou test in the spring? And not flaming, but have you figured the total number of possible combinations

 

[slickerthanyou]

sounds like this is gonna be a very informative test,
too bad we couldnt get a "rad valve" thrown into the mix

Oh no you didn't!! You know the outcome............

 

[PikledBeats]

I'm confused :-/ how do you figure it's 70* in Idaho? Unlessyou test in the spring? And not flaming, but have you figured the total number of possible combinations

70 AVG. Average being the key ... I have re-jetted for weather so many times that I wanted to start at my AVG riding temp then will re-jet appropriately, though I am working right now on trying to secure some Dyno time which is why I felt the importance of doing this before doing my port job. If everything works out (which I'm still working on) I'll be doing dyno runs in a heated shop.

Yes you are correct though that right now we have had a mild winter but my Mikuni is jetted for 40-50 degrees and moisture is playing a role as well.


@AWK, - I got lucky with the PWK, my buddy bought it through Sudco, then blew up his bottom end before installing it. He then traded off his blaster for a trailer frame and I was able to score the carb in a trade which basically cost me nothing ... I would like to get my hands on a RAD valve but with all the intakes/carbs i've been buying, I cant rationalize buying a RAD valve that I might use might not.

 

[slickerthanyou]

YOU guys are gonna make me take this rad valve off for a dyno run and some R&D , I'll do it! Just say when you want it brutha!

 

[PikledBeats]

YOU guys are gonna make me take this rad valve off for a dyno run and some R&D , I'll do it! Just say when you want it brutha!

If everything works out and I can secure the time I'll hit ya up got your # in the PM brutha ... I might have to pay and rent a couple hrs, but the good thing is, when I built the blaster I installed the CFM so it is an easy two bolts and off for easy jet changing making multiple changes possible if my jetting is correct to start. It will take R&D for jetting numbers on the two carbs with all possible setups so I am not guessing hence this thread, so I can get the PWK jetted right and recorded for multiple diffrent setups (jetting changes that is).

 

[slickerthanyou]

If everything works out and I can secure the time I'll hit ya up got your # in the PM brutha ... I might have to pay and rent a couple hrs, but the good thing is, when I built the blaster I installed the CFM so it is an easy two bolts and off for easy jet changing making multiple changes possible if my jetting is correct to start. It will take R&D for jetting numbers on the two carbs with all possible setups so I am not guessing hence this thread, so I can get the PWK jetted right and recorded for multiple diffrent setups (jetting changes that is).

No problem U know how to reach me!!

 

[Larry's Shee]

Very ambitious undertaking to say the least. Dyno or ass dyno? Reguardless the info will be interesting to say the least, and most welcome. Good luck!!

 

[PikledBeats]

Very ambitious undertaking to say the least. Dyno or ass dyno? Reguardless the info will be interesting to say the least, and most welcome. Good luck!!

Dyno, but I'll be the first to say I don't trust dyno numbers, it really is more for comparison reasons than end output. One of the more reputable shops here is where I am trying to work it out. I really am not a fan but figured it was the only way to get accurate comparisons. Take a baseline with stock carb/intake/reed. then go from there making one change at a time. It is something I've been thinking about, and looking into for awhile now, the shop is where I do any local business and yes I am skeptical of anything dyno/atv but I really think for comparisons with a baseline it will work for what I'm trying to do.

 

[PikledBeats]

Any ideas what the jetting change would be if I add my ken oconnor pump gas head mod into the mix.

 

[Blaner]

since i now consider myself VERY well acquainted with jetting the OKO30, i would like to add my condolences in foresight of your fruitless jetting endeavours that shall be performed to no end by youself....

with that said, i have settled with a 165, 55 and bashee needle mid clip

then again because yours is genuine, you will probably get it right first time!!!

 

[slickerthanyou]

Any ideas what the jetting change would be if I add my ken oconnor pump gas head mod into the mix.

That's a good question! I say step up one size, at least that is what I would do, not sure if that is the correct answer or not as i did all those mods at one time!

 

[PikledBeats]

That's a good question! I say step up one size, at least that is what I would do, not sure if that is the correct answer or not as i did all those mods at one time!

I got it close with stock head, still need to run some plug chops though, just curious as I talked to ken today and my modded head will be coming back soon.
And yes I'm always making changes of carbs/intakes/etc. but you guys have always gotten me at a good starting point and I've yet to blow up a motor jetting (knock on wood/fingers crossed) So you think one up on the main or main and pilot?