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What was the first Kawa with a six speed gearbox?
Posted: Tue May 15, 2018 3:51 pm
by H2R
It's ATR in that I want a 6 speeder in my H2, but I can't find what the first model of Kawa was that would have had a 6 speed box. My thinking is that Kawa might have used an existing shift drum with a different cut if it was durable enough rather than create a whole new drum.
Thoughts, anyone?
Thx, Stephen
Re: What was the first Kawa with a six speed gearbox?
Posted: Tue May 15, 2018 7:03 pm
by stevie747
GPz900
Re: What was the first Kawa with a six speed gearbox?
Posted: Tue May 15, 2018 9:26 pm
by Wolfie
Leo and Ralf made a set of billet crankcases some years ago that would take a ZX(?) 6 speed box and they were noticeably larger. In the UK there is just 1 of them.. The Kawacati. I think Ralf himself has the only other one.
I was thinking along your lines some time back and I reckoned it would probably need a dog ring gearbox to fit 6 cogs inside standard cases, which means a very modern item. There will also be a lot of work involved,it's never going to just drop in
Re: What was the first Kawa with a six speed gearbox?
Posted: Tue May 15, 2018 11:55 pm
by husson73
Dave Simmonds H1R had got à six speed gearbox on 1971 made in Italy.
Some crazy italian guys have made 6 speed gear box for H2 or H2R with 1N23456 sometimes ago ( perhaps still available) but you should add a dry clutch made also by them.
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 16, 2018 11:43 pm
by S2Gerald
For what it's worth, my guess is the Z500 from 1980; the 400 and 550 the same and the GPz550D onwards. The gearbox is clearly a relative of that in the triples looking at the selector drum, gear shifter and forks, but I would guess the spacing between the two shafts, diameters and gear ratios would be all over the place compared to a triple.
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 23, 2018 11:33 am
by 666rog
On triples 5 speed boxes, they use three shift forks. On Yamaha 6 speed boxes they have four. They are very compact and beautifully designed. If anyone ever finds an easy way to convert a triple to 6 speed I would love to hear about it.
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 23, 2018 12:35 pm
by SAM
At my age I loose count after 4
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 23, 2018 12:50 pm
by Wolfie
After four what?
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 23, 2018 1:21 pm
by SAM
Wolfie wrote:After four what?
Who said that?
Re: What was the first Kawa with a six speed gearbox?
Posted: Wed May 23, 2018 3:03 pm
by H2R
OK, update time. I've found a 6 speed CR cluster for an H2, but sadly no shift drum or forks. So far I've been unable to find out anything about the shift mechanism other than it fits into H2 cases and uses the 'normal' looking shift arm gubbins, albeit with the upper arm as well, like the S series.
My assumption is that it used a 1-N-2-3-4-5-6 sequence but I have no evidence for that other than that's what the H2 racers used, except for having 5 gears.
Time to dig around some of the race team personnel from the H2R days, maybe they can shed some light ...