SuzukiSavage.com - Keihin PWK38 Air Striker Carburetor Installation

ThumperPaul Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1282 Houston, Texas Gender:	Re: Keihin PWK38 Air Striker Carburetor Installati Reply #45 - 05/15/24 at 11:46:52 Float needle valve looked brand new as it should. It's not the problem...
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Re: Keihin PWK38 Air Striker Carburetor Installati
Reply #46 - 05/15/24 at 12:00:59

Made some reference marks to get float height measurements. First mark is 7mm (6.5mm is spec for an authentic short body pwk38) and 16mm is the other mark (16mm is spec for an authentic long body pwk38). Who knows what the spec is for this knockoff pwk. But, this knockoff PWK must be a long body because there was no way it was going to line up with 7mm. (And yes, I know my lines aren't perfectly straight - close enough!)

My best eyeballing guessimate is the float was set at about 14mm BEFORE I adjusted it to about 16mm. I don't have fancy tools to hold the carb exactly at a 60 degree angle and measure the angle with a protractor. Good ole fiddling back and forth eyeballing the clip and float needle valve as I played with it. I knew I wanted to lower the floats 'some', so I just went 'some' in that direction. I think I move it down about 2mm. Hey, the overflow leak stopped and the bike didn't starve for fuel under WOT or regular riding. I must have done something right! Right?!

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ThumperPaul Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1282 Houston, Texas Gender:	Re: Keihin PWK38 Air Striker Carburetor Installati Reply #47 - 05/15/24 at 12:04:14 Best photo I could get trying to manage the carb in one hand and phone camera in the other. The float height is set to about 16mm. It looked better in person without a phone in my hand and I was fiddling around with it.
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ThumperPaul Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1282 Houston, Texas Gender:	Re: Keihin PWK38 Air Striker Carburetor Installati Reply #48 - 05/15/24 at 12:05:09 Another view fumbling around with it trying to simulate a 60 degree angle.
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ThumperPaul Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1282 Houston, Texas Gender:	Re: Keihin PWK38 Air Striker Carburetor Installati Reply #49 - 05/15/24 at 12:07:33 The clip position after adjustment. The photo before adjustment is crappy. Real technical - I bent it down a little bit.
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Re: Keihin PWK38 Air Striker Carburetor Installati
Reply #50 - 05/15/24 at 12:22:01

And the good news is, I’m 95% happy with the carb jetting/tune. I need some more saddle time testing and MPG testing.

Pilot Jet: 32 (2 turn out on A/F mix screw)
Main Jet: 120
Needle: e-clip middle groove

I might be sensing a little leanness at WOT. I may need to try a 122 main.

The needle e-clip might need to go up 1 groove (leaner). Kinda scared to try this change.

Love the 32 pilot jet setting (easy start, smooth idle, good transition).

I need some more butt dyno testing, but it’s very satisfactory for everyday cruising. I’d consider this a good starting point for anyone considering a PWK38 Air Striker carb for a stock motor with stock exhaust, stock air box with airbox side cover removed. (At steamy hot sea level like Houston.)

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Re: Keihin PWK38 Air Striker Carburetor Installati
Reply #51 - 06/18/24 at 05:30:57

Latest update.

I installed a UNI 4” pod foam filter directly to the carb (no snorkel tube or air box chop job).

Pilot/idle circuit = still great with the #32 jet. Only needed to turn the a/f mix screw about 1/4 turn richer. It’s about 1-3/4 turns out now.

Midrange feels pretty good, maybe a tad rich with the e-clip in the middle groove still.

WOT - While the midrange can find a fairly happy place with a 120, 122, and 125 - I’m struggling a bit to get a nice clean WOT response with the UNI filter installed. The #120 seemed lean. The #125 seemed a little rich. Bought a #122 and I’m perplexed with it. I can’t tell if it’s too small (lean) or too big (rich). It can act “clean” sometimes. If I sneeke up on WOT, it’s generally okay. If I roll on the throttle hard when I think I’m at a good rpm level, it just isn’t clean. It actually backfired out the stock exhaust rather loudly (haven’t heard a bang like that before through the stock exhaust). I’m coming to the conclusion that I need to install the Harley dyna muffler to open things up and get WOT to feel right. Thinking the stock muffler is just too restrictive with the PWK38 and UNI filter.

Thoughts? I wish I could describe the performance feel better. It’s just not always “clean” - like it’s lean sometimes and rich other times. I got the boomer backfire when I was hammering it pretty hard in 2nd. I can creep up to WOT in 4th pretty cleanly. Hit 84mph in 4th getting on it last week.

The UNI filter does sound cool when you can hear the air induction!

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ThumperPaul

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Re: Keihin PWK38 Air Striker Carburetor Installati
Reply #52 - 06/24/24 at 07:57:08

I’m at the point where I think it might be constipated by the restrictive stock muffler.

I got a kaboom on decel in 4th gear when I rolled off from WOT. In 2nd gear, it cuts out when I roll on it hard.

I’m going to bump up to #128 main jet. When I went down from a 125 to a 122, I think I may have misdiagnosed and went the wrong direction. Trying the 128 should tell me something.

I did get 53mpg on a 60 mile ride on Saturday cruising mostly 60-65mph out in the rural backcountry without riding like a yahoo. Bike generally runs great and getting decent MPG, but I want to be able to romp on it without getting the hiccups.

I’m at a place where I can’t tell if I’m a tad too lean or too rich at WOT. And still wondering if it’s a bit rich on the needle in the mid-range or ‘just right’.

A dyno test to see the air fuel mixture across the power band would be great. But the one place I’ve found that can do a dyno on the Savage is majorly backed-up and kinda expensive. So I’m stuck with the butt dyno.

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« Last Edit: 06/24/24 at 13:24:55 by ThumperPaul »

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