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Author Topic: 6 speed ?  (Read 3737 times)

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Offline phil71

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6 speed ?
« on: December 08, 2011, 09:34:20 AM »
Has anyone ever shoehorned a 6 speed gearbox into an SOHC 750 case? Just curious.
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bollingball

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Re: 6 speed ?
« Reply #1 on: December 08, 2011, 10:19:54 AM »
I don't know phil71 but I did read about one years ago. May have been a 550 not sure. Try a post in high performance & racing.

                                              Ken
« Last Edit: December 09, 2011, 09:51:23 AM by bollingball »
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Offline CoachDoc

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Re: 6 speed ?
« Reply #2 on: December 08, 2011, 10:50:31 AM »
.... there you go, this site teasing me again with dreams of that 6th gear my toe is always looking for and will never find.
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Offline faux fiddy

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Re: 6 speed ?
« Reply #3 on: December 08, 2011, 11:43:08 AM »
Look up bwaller's botm/boty  500, it's had a gear added. Actually  a whole 360 transmissoin shoehorned in.

There is a build thread if you look.
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Offline Don R

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Re: 6 speed ?
« Reply #4 on: December 09, 2011, 09:22:36 AM »
I added a tooth to the front sprocket now, my ear thinks it's 6th gear. I've never read of anyone doing it (6 speed) on a 750.
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Offline Duanob

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Re: 6 speed ?
« Reply #5 on: December 09, 2011, 10:54:55 AM »
Quote from: fiddy of industry on December 08, 2011, 11:43:08 AM
Look up bwaller's botm/boty  500, it's had a gear added. Actually  a whole 360 transmissoin shoehorned in.

There is a build thread if you look.

that's what I was thinking unfortunately I don't think the 360 tranny would handle the power and weight of a 750.
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Offline vames

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Re: 6 speed ?
« Reply #6 on: December 09, 2011, 10:58:48 AM »
CB400F -- Just a CB750 shrunken down by 350cc, with a six-speed tranny and a ton of elegance injected.
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Offline Hush

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Re: 6 speed ?
« Reply #7 on: December 09, 2011, 11:06:52 AM »
All SOHC4 owners (except 400f owners) dream of a 6th gear, best I did was add a larger front sprocket, that one extra tooth meant the difference between grinding and cruising on the motorway.
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Offline phil71

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Re: 6 speed ?
« Reply #8 on: December 09, 2011, 12:26:19 PM »
it's got to be do-able.. maybe from a kawi, with some custom cogs & dogs. Or from the DOHC.
Steve, I left an article on your bike... seems that most reviewers also find that bike to be more elegant and usable than it's big , overweight brother!
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Offline camelman

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Re: 6 speed ?
« Reply #9 on: December 09, 2011, 02:27:14 PM »
Can the 400F or 360T 6 speed not handle the 750 power?  I know it sounds silly to ask a transmission from such a small engine to take the power of such a large one, but it seems like these transmissions were completely oversized for the tasks they were given.  I know I read about a turbo 400F that was putting out 80+ HP, and the owner never had transmission issues that he reported.  I would figure from that experience that the 400F trans could handle the 80+ HP easily enough. 

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Offline GammaFlat

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Re: 6 speed ?
« Reply #10 on: December 10, 2011, 05:46:25 PM »
I think I recall HondaMan talking about a 6 speed in a 750.  He mentioned they were very rare but existed (at least at one time).  I think they were for a race application.

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Offline Don R

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Re: 6 speed ?
« Reply #11 on: December 11, 2011, 02:38:26 PM »
Reverse engineering... Could you put a single cam head on a 900 engine with the extra speed in the gearbox? Or maybe have the 750 trans cut off like the dirt car racers do and use a baker 6 speed like the chopper guys use? Just wondering out loud.
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Offline cb650

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Re: 6 speed ?
« Reply #12 on: December 11, 2011, 02:44:42 PM »
Was the 900 a 6?   thought it was just some dual range pos that made it heavier and slower.
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Offline bwaller

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Re: 6 speed ?
« Reply #13 on: December 11, 2011, 04:20:12 PM »
I never saw a 750 with a 6 spd but remember hearing someone offered it back in the day. In my 550 the re-worked CB360 gearbox works well. To be honest getting the thing to fit in the cases wasn't the hardest part, figuring how to manage the shift drum/shift forks & shaft/shifting mechanism was.

In all honesty my race bike makes more power than most stock 750's but weighs a lot less. The problem with the extra weight would be the issue with the small round engagement dogs on a couple gears. As far as narrower gear sets, not an issue.

Sounds like a challenge for someone here to take up.  ;D
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Offline bryanj

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Re: 6 speed ?
« Reply #14 on: December 11, 2011, 11:21:24 PM »
Didn't Honda do them in one of their CR kits, like magnesium caliper brackets
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Offline bwaller

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Re: 6 speed ?
« Reply #15 on: December 12, 2011, 04:42:37 AM »
I believe Honda offered a close ratio 5 speed in their kit parts. I just can't remember who sold the 6 speed, but one would think Nova might be involved?? 
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Offline detdrbuzzard

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Re: 6 speed ?
« Reply #16 on: December 12, 2011, 06:36:52 AM »
the dohc900 and 1000  both had dual range transmissions but they are shft drive
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Offline Don R

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Re: 6 speed ?
« Reply #17 on: December 12, 2011, 10:01:36 AM »
Oh, right I forgot about the shaft. Yes they were dual range, not true 6 speeds.
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