KR-1S.co.uk Forum

Hi Guys,

Has anybody got the details of the KR1R close ratio gearbox or similar?

I'm after at least the top 3 gears to be close ratio.

Why? Because I'm hoping to build an engine for the Manx Grand Prix which is run around the TT course. Regulations may be an issue, seven speeds may pass with a discussion with the technical guys to make sure it's within the 'spirit of the racing'.

Maybe it might be possible to insert another gear, to make seven speed, I think Nova Racing do this for other models (I will give them a shout 01733 210082). Maybe I could adapt something like the Cagiva Mito gearbox? There's probably no hope of using that one but it was a fleeting thought!

Has anybody any information on 60's Grand Prix bikes when they had more than 10 speeds on some bikes? If I remember right some 50cc bikes had 16 gears! Even a hi/lo overdrive on each gear might make some of the corners more manageable....

A KR1 or KR1s with, say, eight gears could or would make an interesting proposition I think!! Especially if close ratios were involved.

Any thoughts are welcome!

Cheers.

Darren - WightWizard.

I remember some time back The Elf had a gearbox made for him, I'm sure he's got the spec somewhere

Hi Scooble,

I've spoken to Graham at Nova Racing and he used to make a lower 5th and 6th gear for the KR1 and KR1S, he tells me this makes the box as a whole much closer ratio and then all you do is modify final gearing.

Makes sense to me. On the mountain roads there are many places for over-revving fifth but not being able to pull sixth on the standard gearing for example.

He said that the bikes were ancient history, or words to that effect, and was a little reluctant to consider dragging the plans out and making some more. I went on a minor charm offensive and he agreed to knock up the two gears that we would need. £125 each so £250 total, he said that they might make a few up so watch this, or his, space.

Any details from The Elf would be gratefully received.

Cheers for now,

Darren - WightWizard.

hi here, i have the nova 5/6th in my bike. on inspection when i rebuilt the motor, the gears looked as new so there definitly top notch. nova have a rep that goes without saying. it does mean it will pull top gear on a well setup bike with ease on say cadwells straight. the other gears are very well spaced, the std 6th though is like over drive in comparison. elf had a full gearset made up at a very reasonable price and i think has the plans. if i wrere you id pm him and get some info. search ''the-elf'' and give him a shout.

Hi mgtkr1,

Sorry for the delay. Been celebrating Christmas!.....

Thanks for your reply, will contact 'the-elf' asap.

Happy new year guys!

Darren - WightWizard.

Sent details via PM.

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the 60's bikes had a gear cluster on the output sprocket (ie outboard of the gearbox) on the final drive chain

so effectively the did have high/low ratios and doubled/tripled the gear ratios available - like a front derailier on a push bike

Hi KR-1R,

Thanks for your reply. That rings a bell from my distant past, probably picked it up watching Grand Prix re-runs in the '70's or something. Have you got any more info? Maybe some pics? Big question: might it be possible to build something like this for a KR1 or similar? Hi/Lo would probably be enough for my purposes.

Happy New Year!

Regards,

Darren - WightWizard.

A tall first, altered second and a lower 6th would be ideal. Most of them could be made by modifiing the addendum on one gear only. I have it written down what the rpm drop and ratios are I devised.
I'll see if I can dig them up.
You could also speak to Ellis Moore at http://www.mpe07.co.uk/ he is very reasonably priced and does excellent work.

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Three speed overdrive Kreidler - 12 speed

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..."in the eary sixties when the bikes were still air cooled, the 50cc class where a high proportion of race time was spent completely flat out, more gears allowed the small engine capacities to stay in the powerband.

New Zealander Hugh Anderson won the world championship (50cc) in 1963 & 1964 on the single cylinder Suzuki - for '63 the engine had 1bhp more horsepower (11bhp total) and 1 more gear in the transmission (9 total). The consequent boost to top speed was 6mph.

Later on the Kreidler bikes went to 18 gears - 9 internal, with a 2 speed overdrive "

a previous discussion on 'R' box...
viewtopic.php?p=40116