Six speed gearbox - Page 4 - Triumph Forum: Triumph Rat Motorcycle Forums
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post #31 of 38 (permalink) Old 10-02-2011, 10:38 PM
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Can't wait to see how this goes...
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post #32 of 38 (permalink) Old 05-24-2012, 01:28 PM
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Any update on this project???

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post #33 of 38 (permalink) Old 05-24-2012, 02:49 PM
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post #34 of 38 (permalink) Old 05-24-2012, 02:54 PM
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Sounds as if he's got it going OK. See post 2 on this thread:
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post #35 of 38 (permalink) Old 06-08-2012, 08:38 AM Thread Starter
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Well, had the six speed gearbox installed and working on the road since last October. I have probably only covered around 4000 miles
The new gearbox runs brilliantly.
I live in an area with lots of hills and winding roads that gives any gearbox a run for its money. The new gear has performed faultlessly and I am very pleased with the end result. Please remember the extra gear fits between fourth and fifth so it does not change your overall gearing just gives you another one to play with. When you are pulling out of a corner hitting 8000rpm in fourth then fifth and powering up in sixth, its just brilliant and has me rapidly chasing down other twins in front of me.
I have had the overall gearing almost stock for the last few months, 19/44 with 160/60 tyre 135mph@8000rpm in sixth. With the many hills and draconian fines for speeding, I have just reduced the overall gearing to 18/44 129mph@8000 in sixth. This has produced a fantastic snap to acceleration with the front wheel skimming across the ripples in tarmac, I just have to be conscious of the occasional wheelie here and there but life’s good. Lol
I generally do not rev my bike over 7500rpm but yes I have hit 8000rpm in sixth gear. (on private roads officer)
Was the extra gear worth it, difficult to answer, if it could have changed the overall gearing, then yes, but with the gear slipping in between two others, for the road then probably not. But If you’re a Thruxton Cup racer, it would give you a massive advantage.
Was it with the expense, hell yes! Would I sell the gearbox – only if offered the right money, so I could finance other mods

Hava already done a few things to the engine
4mm Oversize inlet valves
2mm Oversize exhaust valves
Ported & flowed head 320cfm
790 Cams
Billet barrels ‐ http://www.stabbarps‐
1089cc Wiseco kit 10.5‐1 CR pistons‐
101mm x 68mm bore & stroke
Rebalanced crank
Barnet racing Clutch
Heavy duty clutch springs
Shot preened gears and shafts
Chromed cases

Last edited by Phil-1100; 06-08-2012 at 08:42 AM.
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post #36 of 38 (permalink) Old 06-08-2012, 09:57 AM
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Thanks for the info, and for all of your hard work.


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post #37 of 38 (permalink) Old 06-08-2012, 01:13 PM
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Extra gear's between 4th and 5th? Doesn't seem worth the effort to me, but good on ya for doing it, anyway!
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post #38 of 38 (permalink) Old 12-04-2012, 04:00 PM
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Now the next question, what does it take to change the gearing of 5th (your 6th)?
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