Wacky Wednesday: 600bhp GSX to knock yer socks off

If you hang about at Big CC Racing in Wokingham as much as we do, then seeing a turbocharged Suzuki ends up being a bit like seeing Stacey Solomon or Holly Willoughby on the telly. Very pleasant of course, and you'd be quite happy to spend some getting to know it/her - but not really something that makes you stop and stare, jaw on the deck.

But this beauty is a bit different. It's owner Sean's turbocharged GSX1540 - a hairy-arsed, stone-age behemoth, with all the tech of a modern turbo bike, but plumbed into an old-skool air-cooled GSX1100 motor. Of course, that's been heavily modified, with basically everything except the crank and cases swapped for a performance upgrade. The big alloy lump on the left hand side is a charmingly-brutal chargecooler for the gigantic GTX35R turbo hung behind the wheel, and it uses cooling water to reduce the air intake temperatures, for more power.

Inside, the motor's been bored out to the enormous 1,540cc capacity (from 1135cc), with everything toughened up to handle the power output.Amazingly, the GSX engine has enough space between the bore centres to get this increase without using a stroker crank. The crank is a stock roller bearing part, overhauled, welded and upgraded by Roger Upperton, who also did the head. That features 29mm inlet and 28m exhaust valves, which is a very special setup, with large seats and a total reporting job. Pistons are Wossner turbo parts, inside a bespoke big block set of barrels. The engine management is a full Motec M84 setup, driving some ZZR1400 throttle bodies on a modified cylinder head. Turbo is a Garrett GTX35R, with Tial V-band housing, wastegate and BOV install.

The power output from this setup? Well, Sean at Big CC is aiming at 600bhp, once it's all dialled in. A mighty output from a 1983 touring bike...

Part of the reason for building this bike is to show what can be done with older bikes too. "We're really well set-up to work on older Kawasaki and Suzuki air-cooled bikes," said Sean. "We can sort out stock bikes, or go as far as you want with modified custom work too."

The chassis is almost as interesting as the engine. This is essentially a drag racing bike of course, so we'd expect a big long swingarm, but that is a very rare Spondon-made item, apparently the last one ever made. The Spondon name has been extinguished after Norton took over the company, which means that swingarm is probably going up in value faster than a NOS RG500 fairing...

The GSX is currently away to the fabricator to get a new front end bolted on - Sean's fitting a ZZR1400 USD fork and brakes. There's one major upgrade he's struggling with though - some stock GSX indicators.

"I'm hoping to make it look as stock as I can," he quipped. "Bit of a street sleeper - and with some standard indicators, I think we'll get there."

So if you have some nice OE GSX1100 indicators, give him a shout...

More info: www.bigccracing.com