Needle and Jets Starting Point for Keihin 33mm PWK's

[Strm Trpr]

So, I sold my stock carb set-up in favor of the 33mm PWK's for my future Serval build.

 

What jets and needles do you recommend with the following mods:

 

33mm Keihin PWK's w/K&N's and Outerwears

UPP Intakes w/cross-over tube

VF4's

Mull Pump Gas Head

+4* timing

91 octane w/YamaLube 2R mixed 40:1

stock pistons

stock port

CPI pipes

Sea level in Pismo 75-80* F

 

What pilot?

What needle?

What main?

 

Stock 33mm PWK's come with the following:

52 pilots

CGL needle

165 main jet

 

I talked to a shop and they mentioned the following to start:

48-50 pilots

CGL or CEL needles

155 mains

 

Thoughts?

[locogato11283]

160 main

48 pilot

CEL needle on middle clip

Air screw .5 out

 

Tune the pilot first. Make sure it starts and idles. Make sure you don't have any lean hang.

 

Then go ride it. Couple WOT plug checks. Adjust accordingly.

 

Then adjust needle if needed.

 

Then fine tune air screw.

 

That's how I'd do it anyway.

[Strm Trpr]

160 main

48 pilot

CEL needle on middle clip

Air screw .5 out

 

Tune the pilot first. Make sure it starts and idles. Make sure you don't have any lean hang.

 

Then go ride it. Couple WOT plug checks. Adjust accordingly.

 

Then adjust needle if needed.

 

Then fine tune air screw.

 

That's how I'd do it anyway.

 

Nice, do you think I should buy the following jets and needles.

48 and 50 pilots

CEL Needle

150-152 and 158-160 mains

 

Lean hang? Is that when you stab the throttle and the engine wants to stay rev'd and wont decelerate?

 

The airscrews on 33's are on the air inlet side of the throttle slide correct?

If so, then they'd tune like stock carbs and .5 turns out from seated means rich and I should expect to turn them out to crispen the off idle throttle snap?

[locogato11283]

Nice, do you think I should buy the following jets and needles.

48 and 50 pilots

CEL Needle

150-152 and 158-160 mains

 

Lean hang? Is that when you stab the throttle and the engine wants to stay rev'd and wont decelerate?

 

The airscrews on 33's are on the air inlet side of the throttle slide correct?

If so, then they'd tune like stock carbs and .5 turns out from seated means rich and I should expect to turn them out to crispen the off idle throttle snap?

 

I have a wide variety of jets.. But 158-162 should cover anything you will encounter, even with a bigger motor.

 

Yes, a lean hang is when it won't return to idle.

 

Yes, adjust the air screws to make it rev out clean.

[Strm Trpr]

Awesome, thanks for that!!

OK, so let's say my motor at sea level is running 48 pilots, CEL's middle groove, 160 mains and airscrews 1.5 turns out.

 

What would you recommend my changes be with these same mods for riding at 4,000 ft?

[locogato11283]

What's the difference from the first post?

[Strm Trpr]

Mods, nothing.

Elevation from sea level to 4,000 ft.

I just want to stay on the same page.

[Strm Trpr]

Still need more info.

sleeper06, where you at?

[Strm Trpr]

OK, so let's say my motor at sea level is running 48 pilots, CEL's middle groove, 160 mains and airscrews 1.5 turns out.

 

What would you recommend my changes be with these same mods for riding at 4,000 ft?

[locogato11283]

I'd say 4-5 main sizes and a couple pilot sizes.

[Strm Trpr]

I idle tuned the 33mm Keihin PWK's in about 15 mins.
48 pilots w/Airscrews 1.5 turns out
CEL needle middle groove
155 mains

 

idle set to 1,500rpms w/eBay tach and carbs sync'd at idle with FAST sync tool.

Cold kicking compression is 150psi w/Pump Gas Mull Head

 

Part throttle sync to be done Wed after I get a new throttle cable, then plug chop.

When plug chop looks good, I'm going to add 4* of timing and chop again.
If that looks good I'm going to lean the needle 1 groove to see what happens with a plug chop.

[Strm Trpr]

Bike fires up 1st kick without choke when it's cold, so that's good.

airscrews 1.5 turns out.

 

48 pilot

After a plug chop revealed a slight leaness, I fattened the CEL needles and put the clip on the 4th groove.

I'm going to go from 155 to 160 mains and rechop.

[Strm Trpr]

So, I ended up running the following:

48 pilots, airscrews 2 turns out

CEL needles, 4th groove

160 mains

 

Bike ran like a top all weekend!!