New Bike Gearbox - what are my options??

[JT71]

The gearbox on my ZX9R westy went bang in quite a spectacular way last weekend at Snetterton. What are my options here? At the moment it's being stripped and assessed with a view to potentially replacing a couple of cogs, however this seems to work out as a pretty expensive option (they're talking over £500 in total) bearing in mind you can pick up an entire engine and box second hand for under a grand!! Any thoughts?

Also, is the gearbox a constant source of problems on BEC's? Am I going to spend money on this just to thrash it and suffer an engine / gearbox failure again? With all the hassle I've had from this car in the first few months of ownership I'm beginning to wish I'd bought a car engined westy!

[Jon Ison]

Malc of Yorkshire engines as 2007 ZX10 engines for sale at around £1600 at the moment, I think I would be looking that route.

[Furyous]

The early ZX9C motors did have a weaker box than the later ZX9E.

My Fury had an E motor and was faultless in 3 years of trackdays.

If you have an early motor, I would look to upgrade to the later E.

If its an E thats gone bang, strip it and rebuild it.A few hundred quid on gears and gaskets is better than a grand for a motor.

If you google for the US kawasaki site "buy kawasaki", that has all the parts diagrams and engine number info you require on it.

HTH
F

[LocoBlade]

Do ZX9 donor engines still cost about a grand then? Carbed Blades seem to have dropped to nearer £5-700 these days so I assumed ZX9s were similar, especially as it will be a bare engine as you dont need carbs, loom etc?

[JT71]

Yeah I'm sure I can pick up an old ZX9R engine / gearbox for less than a grand + whatever Colin denyer charges for dropping it in. The other option is £1600 for the 2007 ZX10R engine, 180 bhp is looking quite appealing....(and apparently it's 30kg lighter)...

[Furyous]

Be wary of final drive ratios on the newer bike engines.You could end up with a missile that tops out at 85 mph unless your diff ratio is matched to it.

[JT71]

They're talking about supplying a diff from a freelander meaning it'll top out at 137, which sounds about right. Any thoughts?

[Furyous]

Thats a good diff, light too.

[progers63]

A 2005 ZX10r using a 3.21 (freelander) diff ratio, with 205/60/13 (or 205/50/15) tyres it will reach 127 mph (or 129) at 13000 revs. OK for most tracks but you would be at the rev limiter for Snetterton. So unless the gear ratios have been altered recently, I would treat the claim of 137 mph with a grain of salt.

[JT71]

That's a good point - I was maxing out at Snetterton last weekend on the long straight, and with a more powerful engine you'd hit max I would think halfway down the straight. Any other suggestions for the diff?

[LocoBlade]

There's not many diffs "higher" (numerically lower) than a Freelander, the 3.14 Sierra is the only real option but they're gold plated rocking horse poo so when they come up for sale they seem to go for £3-400.

Im not sure what the gearing on the ZX10 is like but the ZX9 is very low for a litre class engine so I wouldn't draw any direct comparisons with where that tops out, because unless you've already got a 3.2:1 diff or higher in the car it most likely hitting substantially lower than ~130mph on the limiter