250 v 600 = no contest

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THE CBR600 rider in the distance is scything through the pine-lined canyon switchbacks.

His mind is set on one thing – trying to put as much distance between himself and the bike screaming up behind him, my Yamaha TZ250.

I can see from the way he positions his body that he’s ridden this piece of Tarmac before. But at times he looks out of shape, obviously pushing himself and his machine to the limit. After all, he’s on a 600, I’m on a 250 – he can’t let me catch him.

Trouble is, I’m on a road-going version of one of the most successful race bikes ever built. The marque dominated the 250 world championship in the 1970s and ’80s, and now I’m keen to add one more scalp to its collection – that of the fleeing Honda.

This hunt is going to be over in a matter of minutes. My quarry is now filling my visor, and I’m filling his mirrors. I tuck in tight behind the diminutive bodywork to make full use of the track-bred aerodynamics, and wind on the throttle.

As the needle shoots towards the 11,000rpm red line, a shrill from the twin pipes rips through the still atmosphere. The stiff suspension and thin seat are jarring my whole body as the tiny 250cc engine spins hard, but it’s doing the trick.

I’m right in the Honda’s slipstream, the cross-hairs on the TZ’s jet fighter-style screen display centred on the CBR’s tail light. Now it’s just a matter of ducking out to nab the inside line for the next corner, hard on the brakes and with one sweet move I’m past.

The noise from the pipes rattles my brain as I keep the throttle pinned longer than necessary to guarantee I stay ahead. I do, and don’t see the CBR again.

For weekend scratching or the odd track day, the TZ250 is hard to beat. It is a GP bike after all, but it’s not exactly practical. There’s no electric start or even a kickstart. If you want to go for a ride you’ve got to run down the road and bump-start it.

But that doesn’t seem to bother its owner, Mike Derderian, who has spent the best part of £10,000 on this little Yamaha.

In a quest to build something which stood out in a part of southern California where grannies go skateboarding and dogs wear shoes, he employed ex-racer Steve Biganski.

He started out with a chassis from a 1992 TZ and the engine from a ’91 model. The former stayed pretty much unchanged, but the latter, in a bid to make it more reliable and rideable, was detuned.

Biganski also modified the gearbox, the jetting set-up and reworked the pistons and barrels so the bike could run on standard unleaded petrol, rather than high-octane race fuel. Cooling was also a problem and the pair tried several different radiators to ensure the engine ran at optimum temperature. Once he’d perfected the engine, Biganski started bolting on all the bits and pieces to make this race bike road-legal.

Novel solutions were needed for some of the design problems, so the battery pack for the lights now resides in the V of the cylinders and a single beam headlamp sits on a custom-made bracket. The speedo from a bicycle completes the package.

Since it was finished in 1998, the little Yamaha has covered more than 1500 miles. OK, so it won’t sit ticking over at a red light, but that’s part of the fun of running a racer for the road. You just have to rev it all the time.

Derderian is fond of his creation and says he’ll never sell it, no matter how high the offer.

I understand why when I return to his house to find him waiting on the drive. As I recall the CBR story he’s busy cleaning all the dead flies off the screen and washing the brake discs with a toothbrush. When he’s finished, he asks me to help him put it away.

I assume he wants me to assist in gently wheeling it into the garage. Instead, he wants me to hold the doors open while he pushes it into place – in his bedroom. Well, this is California...

YAMAHA TZ250

Cost: £10,000 (est)

Availability: Built to order from Extreme Lean: 001-310-214-2812

Specification

Engine: Air/water-cooled, 249cc (56mm x50.7mm) V-twin two-stroke. 2 x 39mm flat-slide Mikuni carbs. 6 gears

Power and torque: 80bhp, n/a

Weigh: 125kg (275lb)

Performance

Standing 1/4-mile time/terminal speed: 10.2s, 125mph (est)

Top speed: 150mph (depending on gearing)

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MCN Staff

By MCN Staff