FEW Kawasaki ZX-12R or Honda Blackbird owners can honestly say they need more power - but that hasn't stopped the development of two kits to give both bhp beyond belief.
American tuner Muzzy has come up with a bolt-on kit to up the ZX-12R's power from 175bhp to 210bhp by turning the bike into a ZX-14R. And Japanese firm Blue Lightning has devised a turbo kit for the Blackbird which boosts the stock 150bhp to over 200bhp.
Muzzy's ZX-12 kit increases the capacity from 1199cc to 1361cc by upping the bore by 2.4mm to 85.4mm and the stroke by 4mm to 59.4mm.
The big pistons increase the capacity to 1270cc, while the addition of a replacement long-stroke crankshaft takes the engine to the 1361cc mark. Peak power is reached at just 10,000rpm.
A bit of tuning work on the cylinder head and the fitting of a race-spec exhaust system would increase power further - Muzzy claims more than 220bhp is within reach.
But it's more than power the kit provides - it also offers a massive boost in torque. Muzzy claims a peak of more than 120ftlb at just 7500rpm compared to the stock bike's 100ftlb at 8000rpm.
The conversion also provides more than 100bhp all the way from 5000rpm to the red line.
The 1361cc kit costs £1333, though you'll have to give Muzzy your old crankshaft and cylinders in exchange for the new parts. Alternatively, you can pay £2266 and get the whole kit without handing over your old parts. Even then, you can get a refund on the difference if you decide later to send in the old crank and cylinders.
To complete the kit, the bike must be fitted with a Dynojet Power Commander 3 which costs around £250. This allows the fuel injection system to be re-mapped to suit the capacity.
Muzzy's Doug Meyer said: "We've had to extend the swingarm on the 1361cc bike by 3in to help keep it under control on dragstrip runs."
A stock swingarm could still be used on the road, but wheelies could be a problem.
Muzzy will offer even more comprehensive kits including parts such as new camshafts and race exhausts to further increase power outputs in the future. The kit can be ordered at www.muzzys.com
Blue Lightning's approach to tweaking the Blackbird is different. Little is tuned or replaced. Instead, it's the addition of a turbo kit that makes the impact.
It comprises an American-built Garrett turbo, along with a special airbox - or plenum chamber - and a custom-built exhaust. The injection is also recalibrated to provide more fuel.
An extra feature is a boost pressure gauge, which is fitted to the instrument panel to allow the rider to see just how much of the turbo's output he is using - if he can find the time to check the instruments, that is.
The turbo is a particularly small unit which allows it to spin up to maximum rpm more quickly than bulkier fitments used on tuned bikes in the past. Turbo lag is therefore cut down.
The engine's internals are left unchanged as Blue Lightning reckons they can cope with the extra power.
The only other modification is a hole cut in the left fairing panel to accommodate the vital turbo piping.
The entire kit costs around £4500, but it does deliver a massive increase in power output for the 1999 model onwards - though the firm only says "over 200bhp". There's just one problem - it's only available in Japan.
If you want a similar effect, U.S. firm Mr Turbo, which sells adjustable boost systems for other bikes, does a kit for fuel-injected Blackbirds which offers a similar power boost for around £3600.