PWK 28 Jetting Thread 2018..

General forum on engines, transmissions, gearing and modifications to each

Moderator: rztom

JJH? N68X? NAPE? or what? (plz list mods per format in thread)

JJH
5
83%
N68X
0
No votes
NAPE
0
No votes
Other (specify in thread)
1
17%
 
Total votes: 6

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2bang
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PWK 28 Jetting Thread 2018..

#1 Post by 2bang » Wed Jun 06, 2018 9:11 pm

I went back a year in the engines forum and found nothing up to date on the PWK 28s.
Read many old threads... Info scattered over many many pages.. nothing really definitive...
(I realize jetting varies)
Maybe we can organize it in a more useful way, and bring the info up to date?

My hope is that since many have been running around with these for several years now, and
have settled in on jetting (and/or a range), that they feel more comfortable to state for certain
what has worked for them..
Also bring up to date what is available jet/needle wise, and update to a greater level of certainly what/which worked.

Lets put it in a standardized format.
IE: Displacement, stock vs. mods, and which, intake setup (airbox/pods/Yboot/etc) altitude/climate, jets: pilot/needle/cutaway/mains,
and so forth. Just so long as it's the same and same order for all posts.

Hopefully this will become a "sticky-worthy" thread!

I guess it wouldn't be the end of the world if someone posted about other than 28mm PWK, BUT I think it would be best to start a similar thread about those, as well as the various Mikunis..
(a pair of SpecII VM30s in my case)

TIA!

Greg

2bang
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Re: PWK 28 Jetting Thread 2018..

#2 Post by 2bang » Wed Jun 06, 2018 9:26 pm

As for myself:
I'm tackling this now finally, for various reasons..
(partly because I hate like poison to $ rebuild the stockers)
Just assembling the relevant items for now..
Would be helpful to know which jets/needles to order... since these things are getting pricey now..

Bike = 84, Stock bore/stroke, no porting, SCR-cut/squished head, Old toomeys, No airbox but have both Y-Boots and Pods, Sea level and Florida HUMID!

From what I've read, probably should start with 45/145/3.5 and either JJH or N68X (though I haven't been able to determine which of those is richer/leaner and where.. IE: taper)

I can't make heads nor tails of Kehin's needle charts.... though I had Mikuni's practically memorized years ago..

Also, wondering if CPW has a "rebuild kit" and if jet substitutes are OK with them..
(haven't been able to reach them via phone so far)

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pushstartrearset
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Re: PWK 28 Jetting Thread 2018..

#3 Post by pushstartrearset » Mon Jun 11, 2018 6:00 pm

I remember people jumping around from JJJ and JJH needles and maybe? trying to make a stock KX80? carb internals work. Been awhile.

This scooter chart should help explain the needle profile and general jetting. If you can't find a needle to work (28's have a limited selection of needles compared to larger PWK carbs), you might consider a larger PWK or (what i would do) switch to the mikuni that you are familiar w/, either stock or something like a TM...I think Dave Freist (R.I.P.) did one of his mods to the TM as well as the world famous stock mods he did (in conjunction w/ Dale Alexander) w/ OEM A/C RD350/400 carbs.

http://scootrs.com/tech.cfm?tip=tunecarb
1984 RZ350L (U.S.) Old Toomeys, oil injected!, Y-boot K&N. loctite throttle cable holder on left carb!! , 410 mains, Dynojet needles 2.0 clip, #20 pilot @ 1.5 turn a.s., 240/512 p.v.

Bare
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Re: PWK 28 Jetting Thread 2018..

#4 Post by Bare » Mon Jul 02, 2018 11:37 pm

New KX 80 PWKs fitted with 40 airs 130 mains and JJh needles.
Runs Flawlessly.. period.

hondaror
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Re: PWK 28 Jetting Thread 2018..

#5 Post by hondaror » Tue Jul 03, 2018 2:26 pm

I wouldn't change carbs on the Canadian/UK/Aus models unless you were eliminating injection or racing. In the US, I'd buy the above mentioned in used form. The stock 26mm carbs are great, and easily jetted.
Rory

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L.B
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Re: PWK 28 Jetting Thread 2018..

#6 Post by L.B » Tue Jul 03, 2018 7:01 pm

Dont buy Australian parts....they usually flogged to death lol.
Ive done a whole jetting range on jjh & will go back to do it all again with n68 till i find a sweet spot.
Need to give the engine what it needs,not a specific set that someone else using.

graham heise
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Re: PWK 28 Jetting Thread 2018..

#7 Post by graham heise » Sun Jul 08, 2018 6:27 am

i have been fighting with my 30 year old vm26 mikini's and the spare set to give me an in sync range and perfect jetting. i keep searching threads as to alterenatives that can be bought new and deliver a better carb overall . kx 80 pwk carbs jetted to suite is presented to be a good upgrade,maybe second to chambers. i'm willing to turn to the dark side and try something non oem in the pursuit of better performance. who is the best source for a set with jetting?
yamaha fanatic.

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Evans Ward
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Re: PWK 28 Jetting Thread 2018..

#8 Post by Evans Ward » Sun Jul 08, 2018 11:41 am

Lots of tuning and jetting info on this set up over at 2SW site.
84 RZ350-Toomeys,SCR milled head, stk 26 carbs,300 M, 35 P, stock regrooved needles AS 2.5 turns out,stk air box,Banshee reeds Zeel non-progr CDI,TSRL Program YPVS,alum rad,R6 shock,GV emulators w/RT springs,fork brace,Shindy steering damper.

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Re: PWK 28 Jetting Thread 2018..

#9 Post by Bare » Sat Jul 14, 2018 12:15 am

hondaror wrote:I wouldn't change carbs on the Canadian/UK/Aus models unless you were eliminating injection or racing. In the US, I'd buy the above mentioned in used form. The stock 26mm carbs are great, and easily jetted.
I claim Nonsense.
Mikunis were a Mediocre design .. WHEN... Brand New,. let alone with 30+ years age/wear on them.
A set of Fresh 'Genuine' Keihin PWKS, either from Sudco Or Kawasaki (as KX80 parts) are Wonderous things.
A far more evolved /sophisticated design
Their ONLY downside is their cost to purchase
Easy, simple jettings .. where even Passably close jettings yields better result than spot on Mikuni jettings. Very user friendly.
Plus ZERO throttle flat spots.. an Astounding rideability improvement.
Can only surmise that only those that haven't yet ridden/experienced a fitted set of 'healthy" Keihins would even think about questioning their advantages

hondaror
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Re: PWK 28 Jetting Thread 2018..

#10 Post by hondaror » Sat Jul 14, 2018 4:18 am

I would be one of those PWK virgins. Most people do not jet, or do it even close to well. I've never had an issue with the RZ carbs, or LC carbs. I ran RZ carbs on my LC for about 6 years and loved them. PJ carbs.
Maybe one day I'll try a set of PWKs, in fact, I think I have a set of 30s.
Rory

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Questo vecchio rz
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Re: PWK 28 Jetting Thread 2018..

#11 Post by Questo vecchio rz » Sat Jul 14, 2018 1:51 pm

Oh Hogwash (is that still a word....lol).
There's is nothing wrong with the Mikuni carburetor, nothing wrong at all, they perform great, have no problems no problems whatsoever they've been used by millions of people literally millions. Seriously think about that when was the last time any of us have problems with a Mikuni carburetor when it is setup correctly ..Um ...like none of us right?
I used stock 26 mm cabs on several RZs they are awesome for a reliable fast-running street bike I will put them up against anything. They perform so well I won't even really debate it. Same goes for the Banshees they last for years and deliver for years with no problems none?
I also have PWKs they are good as well great actually.
Yes the pwk is and advancement but nothing groundbreaking be it VMs,TMs, PJ,PWK,Airstikers,FCRs,Lectrons..Whatever when set up like they should be, as far as a street bike one should have no problems... set it and forget it unless you're a hardcore 2 stroke racer where you are changing your pipes and rejetting your carbs several times a day during heat races to a final....

Ya got to love forums sometimes.... How about we just say both carbs suck and we'll go fuel injection it's kind of the same logic.

It's all good but the carb banter... Is a little humorous as I don't really recall threads for mikunis but we've had several pwk threads here that go on for years...lol and many here have never been able to get them tuned correctly ?
I'm sure it's the same with anything whichever brand you use but you even get people doing debates with fuel injection with re programmers etcetera.. Aye Yai Yai Amigos :smt028
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(F5)
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Re: PWK 28 Jetting Thread 2018..

#12 Post by (F5) » Sat Jul 14, 2018 4:58 pm

Every bike I've replaced the carb/s with pwk has been an improvement in throttle response.. wonderful for a road bike.

Go on. Try it, you'll like it.

First times free.
496 Cheetah. TSS PVs, PWK35s, Ignitech, RGV(ish) chassis

75RD350rider
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Re: PWK 28 Jetting Thread 2018..

#13 Post by 75RD350rider » Sun Jul 15, 2018 10:42 am

I love the VM30s I put on my RZ. I took the bridged together hour to change a needle clip position EPA 26s off twice and never again... Mine is linear from idle to the rev limiter at 10.5K.
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

tacky1
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Re: PWK 28 Jetting Thread 2018..

#14 Post by tacky1 » Sun Jul 15, 2018 4:26 pm

I run a set of PWK28's on one of my RZ350's and an RZV500 and both bikes are great, Smooth, easy to fiddle with etc.

RuZty
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Re: PWK 28 Jetting Thread 2018..

#15 Post by RuZty » Sun Jul 15, 2018 10:24 pm

Same camp here, I had my VM26s jetted very nicely for my setup, spent a lot of time dialing them in and they worked fine, no real problems, but the PWK28's simply work better all over.

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