Kawi2strokes.com Forum

Just finished jetting H2B engine stock carbs and H2 3-line converted oiling system. Fresh crank, fresh H1 oil pump/yamaha oil check valves, blocked pollution sump check valves, 1st oversize pistons/bore and big honkin UNI foam filters employing two layers and chambers. It ran ok with 102.5 mains for a low stress 300 mile break-in but with 107.5 mains the fun band woke up a bit. I have 105s in the tool box which I might try some day. Plug readings are real nice just like a factory stock machine back in 74 LOL

Final settings H2B

Sea level at 20C
Pilots- stock and well within suggested OEM air-screw range
Needles- 2 clips leaner from OEM (second clip from top)
Mains-107.5

Rototiller if you're running chambers it's a good idea to jet richer on the mains.

Howdy folks. Been a while since I posted.......but been putting in work on the triples. I’ve been playing around with the tuning on this H2 for some time now, tried just about every jet combination under the sun, but I think I have it about right. It took me a while to figure out what was going on with the transition jetting ie; pilot/needle jet area as there was constant hesitation that wouldn’t go away no matter how many jet or slide changes you threw at it, even though the idle screw set was correct for the bike at idle. Found out what it was doing was as soon as the slide opened, vacuum fell on the pilot and the stock float level wasn’t high enough to keep feeding the pilot in that area. The window was so small where the hesitation was, around the 21-23mm needle area, it was quite trying to figure out just what was going on. Every time the mid range and idle were set, the hesitation in that area would come back.

The S3 has been rejetted with the VM30s. Surprisingly, it’s not far off the H2 jetting with the exception of a smaller pilot, smaller main, and using 6DH3.

74 H2 modded with Johns stage 1 kit, VM34-168 and 275, and Uní filters.

VM34-168 x2, VM34-275 x1
40 pilot/1.75 air screw (37.5-45 will throw more fuel at it)
260 main (250-270 can be used)
O-6 needle jet
6DH4 clip 3
2.0 slide
2.0 air jet
Stock float level has to be modded to where the edge of the float arm is level with the bridge between the pilot tube and the main jet tube on the body. Stock float level was causing the imbalance I could not get to go away no matter how many combos were used.

Some combinations to try for mid range

Go leaner
6dh3 clip 3 on O-6 (leans mid section but richens just off idle needle clearance)
6dh2 clip 4 on O-6, clip 3 on O-8 and P-0 (leans entire range)
6dp1 clip 3 on O-8 or p-0 (leaner to around 1/4 throttle)

Go richer
6dh20 clip 3 on O-6
6dh5 clip 3 on O-6

I’ve been doing some new needle clearance diagrams to replace the old ones of mikunis that’s floating around. Some needles don’t match the spec given on the numbering ie; 6dh3 taper starts at 25.5 and not 23 as listed. Once I get them all remapped I’ll send them to Dale for review and possibly adding to the triples resources. I have just about every 6 series needle mikuni sells.

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74 H2B with reeds and 34mm carbs
75 S3A Ram Air with reeds and 30mm carbs
73 S2A (wife's bike)
71 Yammi RT1B
83 HD Sportster
03 Yammi R1
06 Kaw 750 Vulcan (wife’s bike)
12 Yammi vstar 250 (wife’s bike)

Hello Everyone;

Here the jetting spec of my two triples. (I basically live sea level, nice overall temp)

H2
Stock porting, Stock heads
Higgspeed champers (slightly modified baffle)
UNI podfilters
Mikuni TM34 flat slide

pilot 40
main 235
Needle 6FJ6 (2/5 towards lean)
slide: stock

Very clean and crisp, nice plug color.

H1D
Stock porting, Stock heads
Higgspeed champers (slightly modified baffle)
UNI podfilters
Stick VM28 carbs
mixture screw as req.

pilot 35
main 100 (mayhe a hair lean.... I might increase to 105??)
Needle Y32 (2/5 towards lean)
slide: stock
mixture screw as req

Starts well, runs clean. I might go up a little with main since the plugs are a hair too clear. (from 100 to 105??)

Cheers

My H2B at present...

- Port and polished motor ( No tuning)
- Higgspeeds
- TM34s
- Silicone intake runners, long as possible
- K&Ns
- Zeeltronic Iggy on 23 deg flat map

Live in Perth, Western Oz so hot/ temperate climate

- 230 Mains
- 42.5 Pilots
- 6DH3 Needle
- O-0 Needle Jet
- Clip 2nd from top
- Stock float height
- 1/2 Turn out on airscrew

Grabbed these settings from Hawaii_Mike on Dales jetting spreadsheet and feels soooo close for a first go...lovely and crisp, maybe a tad lean off idle..take note of the intake runners..

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1982 Beige Austin Allegro

SquALeD - that information is outdated, at least for my bikes. Here is what I'm running on the H2 now.

50 pilot
6DH3 on the center clip
O-0 needle jet
250 main

The main jet might be too large, I never get up into the high RPM's for very long since we have limited space to ride fast on Oahu.

The bike has John Aylor's reeds. When I switched to the reeds I dropped the needle a notch, to the center clip. Your needle position is probably good.

Richer pilots help get the bike started and run nicely at low RPM's.

Hi Mike,

Yep, saw that you had updated your specs - These settings work well for my setup here so I thought Id post what works for me.

I cant believe how close it is actually for a first go, your (Outdated) settings got me within 99% I reckon - No stuttering etc, pulls into the power real strong with no issues, idles well, just slightly lean just above idle tho I think - may try the richer pilot

Cheers

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1982 Beige Austin Allegro

Good on Ya!

Just asking, this assuming on my part that you are using the 4 oil line cylinders, with no oil passages in the intake ports,

What size intake port oil passage from cases into intake port floor did you add per cylinder when you went to the 3 line early oil pump???

H2R

Too many beers mate?

Or wrong thread?

Kiddin ya, Mines a H2B so 4 line pump

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1982 Beige Austin Allegro