6 SPEED TRANS

NickW900LTD wrote:

can this 6 speed tranny be used in an early kz? Such as a 1000?

Sorry no it can't, only 650 & 750's share the same trans lay out.

Mark Wing wrote:

NickW900LTD wrote:

can this 6 speed tranny be used in an early kz? Such as a 1000?

Sorry no it can't, only 650 & 750's share the same trans lay out.

And possibly the 750 twins, but I haven't had time to check that out real well to confirm it.

I thought I was the only guy searching for 6th gear. Now we all know what these big bikes need

kzwolfsr wrote:

I thought I was the only guy searching for 6th gear. Now we all know what these big bikes need

If you get one you'll be looking for seventh gear

There's very little difference between the 5th gear ratio in the five speed vs the 6th gear ratio in the sixth speed.

The six speed gearbox is just a close ratio trans made for the more peaky 550's.

do you know what the 1st gear ratio is in the 6 speed? most of the time 1st is lowerand 6th is the same as 5th and all the gears inbetween are different

Gear ratio:
6-speed, constant mesh, return shift
Wet multi disc
2.57 (36/14)
1.78 (32/18)
1.38 (29/21 )
1.13 (27/24)
0.96 (25/26)
O.85 (23/27)
For a 500/550 [1980]
Taken from manual in archives.

so here are the ratio's


kz650 kz550


1st 2.33 -- 2.57
2nd 1.63 -- 1.77
3rd 1.27 -- 1.38
4th 1.04 -- 1.125
5th 0.89 -- 0.961
6th ... -- 0.851


soso all the gears are different and 6th gear is higher than 5th so you will get better performance and better milage.:woohoo:

SLEEPER650 wrote:

so here are the ratio's


kz650 kz550


1st 2.33 -- 2.57
2nd 1.63 -- 1.77
3rd 1.27 -- 1.38
4th 1.04 -- 1.125
5th 0.89 -- 0.961
6th ... -- 0.851


soso all the gears are different and 6th gear is higher than 5th so you will get better performance and better milage.:woohoo:

Actually, the KZ550's 6th gear's .851 is only marginally better than the KZ650's 5th gear ratio of .89. The KZ550's stiffer first gear, however, would allow you to change the bike's overall gearing, which would multiply that slight 6th/5th gear difference.

For example, my KZ650 came with 16f/42r sprockets (2.63:1). I initially went with 18f/41r sprockets (2.28:1), but it was way too much. You had to slip the clutch like mad to get it started, and you couldn't roll off from idle in first at all; you'd have to slip the clutch even after it was rolling.

I switched to 17f/41r sprockets (2.41:1)and it is much improved, although I still find myself reaching for 6th gear pretty often. If I had the KZ550's 6-speed gearbox, 6th would be a little lower than the gearing I have, and I could experiment further with the final drive gearing, too. With that stiffer low gear, my 18 tooth front sprocket might work out now, which would also make a big difference in 6th gear. if not, I could at least drop a tooth or two on the rear sprocket. Either way, changing gearboxes gives you a lot more options in final drive gearing; you can't just look at the KZ650's 5th gear ratio and the KZ550's 6th gear ratio and make a judgement based solely on that.

The other problem with highway gearing on these bikes is torque (or lack thereof). When I had the 18f/41r sprockets on, in 5th gear, it was pulling something like 3000 rpms at 55 mph. Hitting the slightest hill caused the bike to scrub speed off tremendously. I believe you could find yourself putting more throttle to it in those conditions, killing the gas mileage you've worked so hard to get.

The other thing I wonder is, with today's modern, overdriven cars cruising at 1600-1800 rpm, would the 6th gear or a change in gearing really make you stop reaching for another gear? The best you're gonna do is cruising at, say 3000 rpm at 55; that's still nearly double the rpms you'd be cruising at the same speed in a car.