Kawi2strokes.com Forum

yep, they're the parts numbers I've got but the 2nd gear cog is identical, the increased bevel on the 4th gear H1 cog would account for the different part number there but I'm pretty sure it won't affect the operation. I'm going to put the transmission in and run through the gears to make sure they mesh and run together ok.

you're right, they wouldn't have different part numbers if the parts were the same and I need to have a closer look because I think I know the difference in the 2nd gear and the 4th gear but since it's 44 degrees C outside and >20 more than that in the shed I'm going to wait 'til tomorrow thanks for your help

What you might to is to only load the two gear sets onto the shafts, then load 'em into the upper case, and see if they "spin" free. If there is ANY binding, the gear climb angle is not compatible (climb is the amount of curvature of the actual tooth).

Lets say the H1 gear tooth face has a 1/2 degree climb, and the H2 has a 3/4 degree climb. If they were to be assembled together, the gears might fit what seems easily, but, would bind as they were turned, as the larger degree cl9imb has more metal in the climb than the lesser degree climb has.

There are also things like root diameter of the gear itself, backlash, and a few more things that can make for trouble, but, lets see what you come up with.

I don't think these parts are interchangeable, but,I only used the 1973 H1 AND H2 parts lists, there are other years listed that might have different gear part numbers.

I do seem to remember there was a gear between the two engines that was the same in the beginning, but, don' remember which one it was, and, if it was changed at a later FDM/production date.

the tooth count for each gear should be in the online manual. The 500 and 750 will be different.

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Thanks for the heads up this morning ---- yeah does not fit. darn..... Not sure how I want to go now. Maybe follow Mikes lead on sending it out? Mike if you catch this did you get yours back from FBG yet?
bb

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This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...

Just a few comments regarding the strength of the H1/H2 transmissions:

If you re-calculate the carrying capacity of each gear set using the same engine power you will discover a small advantage for the H1 transmission (1st & 2nd gear). Overall the Hertzian stress is in both cases is far beyond the limits of the material – simple due to the narrow center distance of the shafts (S-series = 55mm / H-series 50mm) and in addition a lot of friction and therefore loss of power will be generated. Everyone will recognize pitting on the most used gears – no pitting is impossible, it is just a matter of time. The H1 trans use for the low gears a different module resulting in different numbers of teeth. Finally the number of teeth in mesh is slightly increased which does reduce the Hertzian stress. Even if you would use today’s best material for gears – you would not solve the problem (btw Kawasaki used already a good material!!). Considering a higher coefficient of impact delivered by the H2 engine compared to the H1 engine a “thicker” tooth profile makes sense, but I had used both (H1 & H2 trans.) in my H2 an didn’t experience any additional problem. To improve the situation you should alter the center distance which in turn means you need a new crank case. Keeping the current crank case leads to wider gears in conjunction with a different module and tooth profile to achive the min. target of 2 teeth in mesh all the time. In the past we made a six-speed gear box following these rules - even if you think it is impossible.

The funny thing is you will find a lot of information how to hop-up the engine performance but no-one takes care of the transmission. We loose almost about 15 - 20% power due to the power train – so the logic point would be to reduce the loss of power which in addition will reduce the stress of each engine component and. Ok tuning the transmission is quite not as sophisticate as tuning the engine – but at the end makes more sense to do it at the beginning as the loss of power is a percentage of the input rather than constant. Finally the RWHP is what you need for riding – the loss of power from crank to wheel determines how long your engine will last.

My observations on transmissions - I took a 600 Ninja gear set, changed the bearings and it dropped into an S series case. The center to center spacing allows most modern six speed transmissions to fit. The problem, aside from the shift drum, is the clutch hub and how to extend the output shaft three feet. Since the 55mm spacing allows the larger gears more teeth are in contact than smaller diameter gears. However the 50mm spacing of the H series will not allow drop in gear sets (unless custom made). The H series shafts use the same diameter (25mm) and 6 spline as the newer transmissions. Installing the Ninja gears on H1 shafts and proper bearings (one hole in the S case needs to be bored larger for the H bearing) and you have a drop in 6 speed. I am working on a drum and hub but since I am not an engineer it is slow going. You do have to keep the original first gear for the kick start to work. On the H, you would have to weld up the cases and rebore the output shaft bearing holes to make it 55mm spacing. Since I am not an engineer I don't know it will not work so I will be doing that later this year. It has been at least 6 years since I last worked on this project so my info may be a little off but I will be back on my old projects later this month after I finish school and have my life back.

a dozen or so years ago there was a discussion about this as I was fitting an H1 trans in an H2 engine. The arguments for the H1 transmission (in regards to "strength") was that more than one set of teeth are engaged (or partially engaged) in any gear, which gives more surface area to carry the drive-load.
This was, of course, countered by the "big teeth, with big roots are more better" camp.

At the end of the day, these transmissions pretty much suck regardless as far as "longevity" goes. To me, they are the most fragile thing on a Kawasaki Triple. I don't know if I've ever split a set of cases and seen a "perfect" transmission? They have ALL needed at least a shift fork, and usually a gear or two.

I think for the majority of us (who barely ride these bikes a 1000 miles a year), an H1 tranny in set of H2 cases is just fine. If it craps out, throw another one in there.... Like was stated, H1 transmissions (at least for the time being) are "cheap as chips" compared to a good H2 box.

IMHO, the most important thing in making an H-series box "live" is making sure it is shimmed properly, and using FIRM shifts with your foot, making sure it is FULLY ENGAGED before getting back on the power. Lazy Shifting=Dead Trannies.

Cody brings up a good point that gets lost sometimes. The pot metal shifter assembly wears rather quickly ending up with a lot of slop in the shifter. This causes partial shifts, and gears popping out. It only takes a few to cause dog/fork damage. There should be a few threads on fixing this problem. I think JRD here has a fix.

The main thing on these gals, is getting used to lightly loading the shifter to take out any slop before up shifting, then pulling in the clutch (if you use it for upshifts) up shifting and holding the shifter up until after you let the clutch lever out. This positively sets the gear in a full engagement, greatly reducing chances of a missed shift.

_________________
Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

My dogs are good - I knew about the pre-load before. Jeff did my changer long ago (awesome work BTW) Side note -- he did my pump too - the guy is righteous with this stuff.

_________________
This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...