Sigma Ducati 853s

Published: 01 October 2001

Not everyone is a fan of Ducati’s 748. There’s no doubt it’s as beautiful as the 916 or 996 but because of its smaller capacity it just doesn’t have the same credibility.

Its revvy engine that’s less lumpy than the 916, and it handles as well as, if not better than the 916. But the fact remains that it’s just not a 916. And that’s its only real problem. So imagine Ducati had pitched the gap between the 748 and the 916. A bike with the same revvy nature as a 748 but with also as much guts as a 916. Now that would be a bike worth riding. And that’s exactly what you can get by splashing out around £1500 to turn the standard 748 or 748R in to an real street sleeper – an 853. Not a genuine Ducati kit but a bike that feels like it could have been bought from a showroom all the same thanks to the superb work by Neil Spalding at Sigma Performance. In fact Sigma has built two of them and they are both fantastic bikes in their own respects. First is the 748R that’s now fitted with the 853 kit. The bike started life as a standard 748R with the close ratio gearbox and extra power to begin with. But after a season racing in the Supersport 600 class Spalding fitted the bike with an 853 kit and has now got a bike that makes more power than some 996SPS. The other one is a standard road bike that looks identical to any other 748 but what’s beneath the fairing makes it in to a totally different bike to ride.

Both bikes were taken to Ducati’s own track day at Silverstone a couple of weeks ago along with a standard 748 to compare them against. It’s a long time since I’ve been near a 748 so I rode it to the circuit to get familiarised again. To all ends it’s basically an understressed 916 with slightly lighter flywheels and a closer ratio gearbox than the 916.

And although it’s not hugely fast in a straight line it is a quick cross-country bike that in many ways is more fun to ride than a 916. It’s more revvy and you have to keep the revs up to make it go quick so it’s a lot more involving than the lazy 916. It makes all the right noises and the handling is great on the road but although it’s revvy for a twin it hasn’t quite got the 916’s soul.

After a session at Silverstone to get used to the bike again I take out the sem-standard 853 road bike with the top-end clean up and bigger 94mm pistons instead of the standard 748’s 88mm pistons. The pistons weigh exactly the same as the standard pistons so the crank doesn’t have to be rebalanced. The head is also modified to make it breath better and improve gas flow and compression is also up and the engine mapping redone to suit.

It feels like any other 748 to sit on but fire it up and the exhaust cans give a slightly deeper bass rumble than a 748 with aftermarket cans does normally.

The obvious increase in bottom end is obvious straightaway leaving pitlane and once out on the track after a gentle lap to warm it up I catch up with Dave Hill on the standard 748.

On the short circuit the track cuts past pit lane, there’s a mega fast right hander then it opens out in to a chicane before the track pulls right out on to the back straight.

I’m right with him in the chicane and get on the power hard coming out of the right hander as the track opens out. Straight away the bike starts pulling yards on him on the way out of the corner and by the end of the back straight it’s a good four bike lengths ahead.

Where the standard 748 keeps making noise but not much more power the 853 keeps pulling hard and revs on more like a 916SPS.

It might not be cheap but the 853 conversion is definitely a modification worth the money and would be even more noticeable on the road where you spend the most time riding the bike in the midrange.

The next stage up is the 853 race bike that is more powerful than most 916SPS and it’s quite a tool. The bike was already a 748R with a race tuned motor and close ratio gearbox and in 853 spec it’s an absolute animal that can’t be touched by proper full-size Ducatis.

The chassis is also tweaked with an Ohlins rear shock and the adjustable steering head angle on the fastest turn setting. Off the bottom the bike’s a bit fluffy. It’s a race bike after all but once it’s past 5000rpm the bike kicks and revs well on to 12,500rpm before the shift light on the very cool Stacks race clocks flashes its redlight.

Out of lower speed corners you have to be very accurate on the throttle as it’s a bit snatchy on low speed turns. But once you’re used to that you can get on the gas hard and no that barely any other Ducati out on the circuit will get near you. The way the bike’s midrange power comes in totally takes you by surprise but the chassis is so well set-up it lets you get on the power hard and be committed snicking it up through the close box for as long as you dare between corners.

But this is the ultimate incarnation of the 853 and would be a bit unrideable on the road. If you really must mess with your 748 then the basic conversion fills the gap between 748 and 916 perfectly without any of the real peakiness of the 916SPS.

For conversion details contact sigma.performance.com or call Sigma Performance on: 0788-1820-748, email neil@sigmaperformance.com or visit the website at http://www.sigmaperformance.com