I'm looking at a Hayabusa 1300 engine and breaking it down and selling the bits to fund the gearbox conversion, I'm unsure yet on how much load the gearbox will take or I should go for another bike engine with a stronger gearbox?

I've seen enough photo's of inside of the box to have a go at making the gearbox conversion with bellhousing to fit a 3.5 V8 Rover engine. Lots of fabricating and machining involved.
I know I'll get people saying, eh, why would you want to do that? Waste of time and effort.


Because it probably hasn't been done before??? A cheaper alternative to a proper dog ring box. I love the sequential dog ring gearbox, synchro box is too slow.
I just want something a bit different.

I'll rebuild the engine with a performance cam, that will bring the HP up to about 190ish and drop the torque to about 160lbs, hopefully. I still think the gearbox may grenade itself so I'm after other thoughts on a stronger gearbox out of a bike.


Kev

ihave a nice 06 hayabusa engine but has a conrod bearing failure so needs a rebuild ..

07737814426

£1200

We're all for doing things "because you can" here, but I for one would hate to see so much time money and effort wasted.
Maths and metallurgy aside I think it would last 5 minutes, but as ever I'm happy to be proved wrong

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Originally posted by big_l
ihave a nice 06 hayabusa engine but has a conrod bearing failure so needs a rebuild ..

07737814426

£1200

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Originally posted by ReMan
We're all for doing things "because you can" here, but I for one would hate to see so much time money and effort wasted.
Maths and metallurgy aside I think it would last 5 minutes, but as ever I'm happy to be proved wrong

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Strong+Bike gearbox
I'd have thought the Busa would be about as strong as they come, being at the "torquey" end of the scale

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Originally posted by KFC

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Originally posted by ReMan
We're all for doing things "because you can" here, but I for one would hate to see so much time money and effort wasted.
Maths and metallurgy aside I think it would last 5 minutes, but as ever I'm happy to be proved wrong

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Yeah, I'm thinking the same. I've seen a 265bhp Hayabusa on pistonheads and seems to go fine but mine will be 150kg heavier, it's the torque of the V8 I think will strip the gears.

Any ideas for a stronger bike gearbox?

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I like the idea of a busa box, why not connect it to a high reving powerful engine, maybe something from the suzuki motorcycle range.

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Originally posted by matt_gsxr
I like the idea of a busa box, why not connect it to a high reving powerful engine, maybe something from the suzuki motorcycle range.

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Duncan Calper runs over 500bhp in his busa turbo Dax, not sure if he's uprated the box, but shows they can take alot of power, so can't see any reason why it can't be done

Can't imagine any bike box coping with the torque of a V8, everything in them is tiny compared to any car boxes
i can think of that are up to handling even a modest V8 like the rover. Car boxes are big and heavy for a reason

Its easy enough to wreck a bec box using the standard bike engine if you are hard with them on the downshifts.
Would love to think it was possible, but reckon it's a complete non starter.

Al.

I too would love to see it done but think it hasn't been done much for a reason. As above, theres a reason CEC sequentials are big heavy jobs.... Yeah it'd cope with the power but i don't think anyone has got that much torque out of a busa and you'll always be on the limits of the box.

If you've got lots of time and money to chuck at it to be different, then go for it. If for whatever reason you dont, then don't.

You'll probably get through a few gearboxes getting it right, so budget for that

Good luck and let us know if you go for it.

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Originally posted by MakeEverything

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Originally posted by KFC

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Originally posted by ReMan
We're all for doing things "because you can" here, but I for one would hate to see so much time money and effort wasted.
Maths and metallurgy aside I think it would last 5 minutes, but as ever I'm happy to be proved wrong

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Yeah, I'm thinking the same. I've seen a 265bhp Hayabusa on pistonheads and seems to go fine but mine will be 150kg heavier, it's the torque of the V8 I think will strip the gears.

Any ideas for a stronger bike gearbox?

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Look at the big V-Twin gearboxes that go into choppers etc. lots of torque in those.

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I also know when I purchased my turbo kit from Velocity in the USA, they ran a drag Hyabusa with over 700bhp with a massive 10/11" wide slick tyre, which did 6 seconds 1/4 miles on a stock gearbox

Rover V8 approx 200ft lb torque, turboed 'busa lump with 300 bhp and same ftlb

Torque is torque whether it comes from a V8 or bike 4 cyl so why should having 200 torques from a V8 make it more likely to strip the teeth of any cogs that are ok with 200+ torques from a modded bike engine..

Edited to say, Triumph Rocket III has just under 170ftlb.

ATB

Simon

[Edited on 2/7/12 by Simon]

I think a more likely project would be to use one of DSG type gearboxes available on modern cars. Or even a modern auto box with aftermarket shift computer and paddle shifts.- something from Mercedes or BMW for instance.

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Originally posted by Simon
Rover V8 approx 200ft lb torque, turboed 'busa lump with 300 bhp and same ftlb

Torque is torque whether it comes from a V8 or bike 4 cyl so why should having 200 torques from a V8 make it more likely to strip the teeth of any cogs that are ok with 200+ torques from a modded bike engine..

Edited to say, Triumph Rocket III has just under 170ftlb.

ATB

Simon

[Edited on 2/7/12 by Simon]

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Don't try and be logical, everybody knows that V8 "torques" are much bigger than regular ones, there is no scientific theory available at the moment to explain this phenomenon but Jeremy Clarkson and other great thinkers are working tirelessly in search of the truth.

I however agree with you and suspect that it may be to do with the primary reduction ratio.

Cheers
Davie

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Originally posted by Simon
Rover V8 approx 200ft lb torque, turboed 'busa lump with 300 bhp and same ftlb

Torque is torque whether it comes from a V8 or bike 4 cyl so why should having 200 torques from a V8 make it more likely to strip the teeth of any cogs that are ok with 200+ torques from a modded bike engine..

Edited to say, Triumph Rocket III has just under 170ftlb.

ATB

Simon

[Edited on 2/7/12 by Simon]

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Turbo is key to more lbs/ft from a BEC, but isn't the right question:- Is this less than the tyres will take before spinning in the intended use.

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Originally posted by kjouk
Turbo is key to more lbs/ft from a BEC, but isn't the right question:- Is this less than the tyres will take before spinning in the intended use.

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So the steady-state torque can (probably) be handled, but what about the higher inertia of a car engine and hence the dynamic shock loads.
What I mean is, when you change gear and the engine speed doesn't match then with a bike engine the angular momentum is small and so the forces to slow the engine are small. With a car engine the inertia is massive (compare the crank-shafts, and flywheels), I wouldn't be surprised if v8 angular momentum wasn't 10x that of a bike engine. I think these dynamic forces will knacker the box.


The other thing to consider is how you will get the power into the gearbox. By this I mean, on the bike there is the final reduction gear that drives the clutch and hence the box. This doesn't fit so well with the way a car engine drives things.

If you do away with the final reduction gear then that will affect torque that gets dumped into the box, and also will affect the final gearing that you will need from your differential to get sensible speeds.


Matt