Author Topic: Cb750 road racers, 2nd gear use on track.  (Read 1111 times)

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Offline gschuld

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Cb750 road racers, 2nd gear use on track.
« on: July 13, 2019, 01:45:05 pm »
I’d like to know how often road racers make use of 2nd gear while racing(other than at the start of course).  It could only be during quite slow and tight corners naturally.

George

Offline turboguzzi

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Re: Cb750 road racers, 2nd gear use on track.
« Reply #1 on: July 14, 2019, 07:58:30 am »
Exactly!

Offline gschuld

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Re: Cb750 road racers, 2nd gear use on track.
« Reply #2 on: July 14, 2019, 08:26:13 am »
Yossef,

The Honda RSC 970 kit close ratio trans, for example, had 1st gear at the same ratio as 2nd gear in a factory trans.  That makes the close ratio trans a bit more sluggish off the line of course, but I’m wondering it would have been useful on the track in slow corners, especially with the higher revving, narrower power band engines.

If it can be use effectively, that would make the RSC trans a true usable 5 speed close ratio on the track where the factory is a wider 4 speed with both having nearly the same final gear ratio.

If it can’t be used, the RSC is using 4 close ratio speeds once under way rather than 3 wider ones on the factory trans.

George

Edit:  I just found this nugget of info from the big CR750 Daytona thread.(image)

« Last Edit: July 14, 2019, 09:18:10 am by gschuld »

Offline turboguzzi

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Re: Cb750 road racers, 2nd gear use on track.
« Reply #3 on: July 14, 2019, 09:35:10 am »
if you are talking about close ratio sets, then forget my comment.
with stock ratios, i use 1st once only to start, then it's 2nd for even the slowest corners, 1st just not usable, anywhere.
maybe you need to rephrase your question.... is it good having a close ratio set?
answer would be of course yes, if you can afford it. I cant...

Offline gschuld

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Re: Cb750 road racers, 2nd gear use on track.
« Reply #4 on: July 14, 2019, 11:58:20 am »
Yossef,

Sorry I wasn’t clear.  I asked about 2nd gear usage of a FACTORY trans for road racing because that’s what the vast majority of cb750 racers are using.  The 2nd gear of a factory trans is the same ratio as the original RSC close ratio 1st gear.

But yes, my real interest is in judging how functional a rare vintage RSC 1st gear would be beyond the start while racing.

George


Offline bwaller

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Re: Cb750 road racers, 2nd gear use on track.
« Reply #5 on: July 14, 2019, 02:18:43 pm »
Surely riders use 2nd on some/most tracks, otherwise their 5spd gearbox is limited to 3 speeds. Final gearing options maybe! Obviously tracks are different but usually there is one tight hairpin. I can think of a few spots on the tracks we race where you could probably get into that tall 1st gear in your RSC box George.