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PostPosted: Sun Dec 30, 2012 6:57 pm 
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Joined: Wed Jun 22, 2011 8:07 pm
Posts: 1739
Location: houston texas
just fitted ivans kit today.

H1D motor

Carb Type: OEM
Pilot size: 35.
Needle: IVANS
Clip:MIDDLE groove
Needle Jet: IVANS
Main: 107.5
Slide: OEM
Engine Size: 500
Porting: STOCK
Heads: STOCK

Air Filter: UNI filters(with plumbing elbows)
Altitude: 70 ft

she will never be pretty but she is a fun ride.

73 KAWASAKI H1 (Sold).
2000 KAWI KDX200H

PostPosted: Mon Apr 08, 2013 6:03 pm 
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Joined: Mon Jun 13, 2011 7:14 pm
Posts: 929
Location: Martinsburg, WV
Mines kinda a poor example but ill post it. This looks to be the final setting for this bike.

S3A modified engine
Mikuni VM30-83
40 pilot
250 main
6dp1 jet needle on middle
P6 needle jet
3.0 slide
Elevation is 2000' give or take (been to 3k and no change)

Engine mods (as I said, bad example)

Cylinder decked 2mm
Cylinders shimmed up .5mm
Intakes planed +2 degrees
Boost port added to rear of cylinder
Bored .20 over, pistons are holed for more intake duration.
Exhaust port raised 1mm to bring compression down.
John's stage 2 kit
Jim's denco pipes
Air box converted to ram air induction
15 tooth sprocket

74 H2B with reeds and 34mm carbs
75 S3A Ram Air with reeds and 30mm carbs
73 S2A (wife's bike, may keep this one as is)
71 Yammi RT1B
83 HD Sportster
03 Yammi R1

Last edited by usernameandpassword on Thu Jun 06, 2013 3:42 pm, edited 3 times in total.

PostPosted: Mon Apr 15, 2013 7:39 pm 
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Joined: Thu Jun 09, 2011 4:40 pm
Posts: 93
Location: NW Indiana
1976-KH500....Elevation 800ft.
Piston:Wiseco,2nd bore
Stock carb:97.5 Main,32.5 Pilot
Needle clip: 2nd postion
Airfilter:Unifilter pods-4 1/2in.
Oil:Maxima 927 @ 40:1
Fuel:70%-93 Octane and 30%-VP110 Octane

PostPosted: Fri Jun 21, 2013 1:18 am 
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Joined: Sun Jul 17, 2011 8:26 pm
Posts: 225
Location: Breese, IL
Edit. never take my advise on jetting

PostPosted: Sat Oct 19, 2013 9:19 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 822
Location: Honolulu
My '75 H2 has 30mm (stock) carbs with Ivan's jet kit. I've been using Ivan's for several months and have been carefully making changes. The bike has Wirges pipes and uni pods.

Here's where I'm at now.

- 37.5 pilots.
- air screws about 1 1/4 to 1 1/2 turns out, varies with each carb.
- needle clips in the center slot.
- 107.5 main jets.

I just changed from 110 to 107.5 mains today. That made quite a difference. I was wondering why the WOT speed was not that fast and the bike was not blubbery. But the main jet change did wake it up and I didn't hear any pinging. Might actually be able to go down to 105's but I'll stay with this for awhile and see how it goes.

Last edited by Hawaii-Mike on Sun Mar 09, 2014 9:38 pm, edited 1 time in total.

PostPosted: Wed Oct 23, 2013 11:22 pm 

Joined: Tue Jan 01, 2013 1:24 am
Posts: 2
1975 500
28 Mikuni's
0.05 over
J n R's
100 mains
30 pilot
needle on last clip (leanest)
1 1/4 out
4 inch Uni's
Riverside, Ca., elevation 600-800, 68-75 degrees winter, 85-105 (up to 114) summer
Nice and strong after 3000, I think I need to drop down my pilots because I almost have to fan my clutch to take off, after that, watch out!

PostPosted: Tue Sep 23, 2014 5:02 pm 

Joined: Tue Jul 24, 2012 6:06 pm
Posts: 822
Location: Honolulu
1976 KH400 with K2tec chambers.

Mains 92.5
Pilots 22.5
Needles (stock) are on the leanest position, clip at the top.

 Post subject: Re: here's my specs...
PostPosted: Sat Sep 27, 2014 2:33 pm 
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Joined: Wed Jun 08, 2011 10:04 pm
Posts: 2188
Location: Just north of Toronto, Ontario
An update..
H1D motor

Carb Type: Keihin PWK 35mm
Pilot size: 38
Needle: AJP
Clip:2nd groove (lean)
Needle Jet: N/A
Main: 175
Slide: 6.0
Engine Size: 525
Porting: Stage 2.1
Heads: Squished
Note: JA reeds (gen1 stage2)

Cut Piston: just a couple slots
Air Filter: UNI filters
Chambers: Clough
Altitude: 1426 ft (1' higher while in 1st and 2nd)

:wtf: :wtf: :wtf:


PostPosted: Mon Jul 06, 2015 1:45 pm 
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Joined: Mon Jun 13, 2011 7:14 pm
Posts: 929
Location: Martinsburg, WV
I thought I'd post a jetting update on my bike. I've gone through quite a bit of carb tuning on this 400 and hope that it will help someone down the road. I've tried various needles/needle jets/mains/pilots/float settings and found a few that work on this bike, dependent on other carb adjustments. Hopefully I've outlined these well enough and my trial and error will assist someone else with a decent starting point.

The VM30-83 will run on this bike with it's stock setup, porting and all, but any aggressive carb tipping (>15 degrees) will cause the pilot circuit to blubber a bit depending on the tilt of the bike (downhill), indicating the pilot is pouring too much fuel into the engine from the float height and excessive lean of the carb. The stock settings for this carb can be found here.


The stock float adjustment is set to 24mm. When these are added to John's stage 2 reed kit, the carb will be tipped near 20 degrees, which will require a float adjustment on this carb. Currently I have mine set to 27mm and that setting is strongly recommended for 3 reasons; 1. excessive blubbering just off idle during decels or excessive idling at lights. 2. keeps the pilot circuit from pulling too much fuel during decel or excessive downhill running at high vacuum, and 3. leaking fuel through the pilot into the engine when sitting with the fuel on, should the fuel inlet develop a small leak from a bad or dirty seat. I experienced this once and had to pull the plugs and run the engine downhill in gear to clear it out before starting, so I didn’t bend a rod. The fuel level at the front of the carb is near the gasket surface on the stock setting @20 degrees and the pilot can't regulate it properly if the float level is too high. Once the fuel level is changed to 27mm, the stock carb settings will be too lean on the needle, all other settings will be unaffected. Adjusting the needle up or enlarging the needle jet to compensate only makes the decel problem worse because of the drastic clearance on the needle at the 20-30mm mark, and leaning the needle jet will only lead to the same lean problem with the needle at other positions.

At 27mm, I have found 4 combinations of jetting that work on this engine, so hopefully this will give someone a decent starting point.

1. 40 pilot, P6 needle jet (P4-P6 are useable for some adjustment), 6DP1 needle (clip on 2), 3.0 slide, 2 turns out on the air screw, leave in the 2.0 air jet, 250 main

This will make the engine run pretty clean at lower settings but will throw more fuel at the bike at higher throttle openings. You can expect strong throttle response once the 6k spot is met and surpassed, and it will accept full throttle for a duration, but lower RPMs around 4k with excessive throttle openings may appear to throw too much fuel to the bike, leading to some blubber during shifting and/or quick closing of the throttle while upshifting.

2. 40 pilot (37.5 can be used but no less), P5 needle jet (P4 can be used, P6 and up are too hot), 6CF1 needle (clip on 2), 3.0 slide, 2.25 air screw turns out, take out the 2.0 air jet, 250 main

This gives a pretty decent response all around but will lead to some small blubbering just off idle, especially downhill, for just a second until it's throat clears, but mainly during upshifts or strong decels downhill. This combination does work well on other areas and will provide a clean and hard pull once the powerband comes in around 6k. I ran this for a few weeks and was very impressed with the throttle response.

FYI when looking at Sudco or Mikuni's jetting numbers, the taper is said to start at 29.5 but this looks to be inaccurate taking measurements on the needle, where the taper point actually exists, and looking at Mikuni's flow charts. This needle's taper starts at 23.5, which is why some constant blubbering is noted just off idle to around 1/8. The needle cant be 2.512@20mm, then go to 2.429 at 30mm, with a taper starting at 29.5, without this being a stepped needle like other F series needles. This needle is not stepped and shows the taper to begin at 23.5mm based on my measurements.

3. 40 pilot, P5 needle jet, 6F21 (clip on 3), 2.5 slide, 2.0 air jet, 1.75 turns on air screw, 250 main.

This has a very crisp throttle response and good acceleration @ 1/4 throttle and up, but has a small lean spot just at 1/8. This could likely be compensated out with a 2.0 slide but I did not have one available to test with it. Raising the needle will give it more fuel than required at larger openings and leaves a smaller lean spot at 1/8, so it does help, however, the setting would probably benefit better with a 2.0 slide than to raise the needle or enlarge the needle jet. I seem to find that the taper start point with this needle appears to be the prevalent problem with the lean spot.

Currently I am running.....

4. 40 pilot, P5 needle jet, 6F15 (clip on 3), 3.0 slide, 2.0 air jet, 2 turns on air screw, 250 main

This setting is a shade rich on larger throttle openings at lower RPMs but once revved up to 5500, it likes the additional fuel with the powerband. It has the same pull as with 6CF1, strong and very assertive. I have not pulled the air jet out for a comparison but likely wont need to. Very satisfied with the way the bike runs.

If I had to make a recommendation, I would try some of the F needles I have identified before moving to the 6DP1 setting, as the motor likes the F needle tapers. As I make more incremental adjustments, I will update this, but I’m going to leave this setting for a while. Keep in mind that I am still running the ram air configuration on this bike so some settings may vary a little at freeway speeds with Unis or such without any ram air.

74 H2B with reeds and 34mm carbs
75 S3A Ram Air with reeds and 30mm carbs
73 S2A (wife's bike, may keep this one as is)
71 Yammi RT1B
83 HD Sportster
03 Yammi R1

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