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May '99 - Yellow Brick Road

Why make life hard on yourself and pick a 748 for Sport Production?
It's all about passion

At the dyno
It seemed such a nice idea at the end of last year, do some racing in the UK, try and use the knowledge gained in the last few years, what happened? It is now only one week to the first race and we still haven't finished the bike.

We, that is Sigma Racing, which sounds very grand but actually consists of me and a few very good friends (the team), have entered the British Sport Production Championship.  This is a full British Championship, but run at a few different meetings as well as some British Superbike events.  The big attraction when we decide to go for it was that we could race at the two British Superbike rounds as well as the British Grands Prix. The World Superbike part of the plan has disappeared with the new timetable designed to fit in the World Sidecar class and with it a lot of the attraction to various sponsors.  Interestingly enough there is a class at World Superbike, Superstock which uses the same basic rule book, so there may be a chance yet!

The class is divided in two to allow for an unlimited category as well as a 600 class. The 600's will also allow in 750 twins just like World Supersport but unlike British Supersport (although I have no idea why).  The rules are based on the FIM Superstock class, and are very clear about what can be changed, which is very little. The few differences between the two rulebooks seem just enough to cause confusion, and not enough to make any real difference.

With the Supermono class out of Superbike meetings, (no factory supporting the class in the background!) it seemed wrong to get up to speed and then just walk away so the 'mono has gone and been replaced with a 748SPS Ducati. Now it might seem a bit contrary to go racing with a five year old design in a class where our main opposition have brand new motorcycles this year, but the simple fact is I love my Ducati's and if I am going to put my money where my mouth is, I am going to do it with a machine that I like.

Two days after we got hold of the bike it was coming apart. While we will not be doing many miles in the year, it still makes sense to ensure everything is built exactly right. A year with the Ducati Supermono had taught us a few important lessons and we decided there was going to be a lot less uncertainty if we built and checked everything ourselves. Events would prove this was largely unnecessary but starting with a pile of bits and getting really familiar with all aspects of the machine is a habit you get into after a few years racing.

There is a lot to getting an undertaking like this underway, first you need a marathon rule reading session, then setting out a list of things to do, though much smaller than a Supersport effort (and much, much less than a Supermono effort) the resulting list is still way too long.  The first thing I did was to speak to everyone I knew with 748 racing experience, not many people it has to be said, to get as many ideas as possible. 

The main bits of bike you can change in Sport Production are bits of the suspension, the bodywork, the tailpipes and jetting (or in the case of the Ducati the Eprom chip in the Weber fuel injection system). Concentrating on the Suspension side of things it rapidly became obvious that most people thought the standard suspension was pretty good, the bike comes with an Ohlins damper on the back and upside down Showa's on the front.  The bikes standard chassis also includes adjustments for the angle of the headstock and ride height.   After a few phone calls I found myself speaking to Ken Somerton and Lester Harris and getting hold of a job lot of front and rear springs to give us something to try in practice.

The rulebook uses the same wording for a lot of sections for Sport Production and Supersport so, after a long chat with Barry Hibbert (the man who must have the most thankless task in motorcycling, being Series Scrutineer for a production race series) a phone call went into that maestro of aftermarket bodywork John Merrill of QB Carbon.  Could he make a couple of sets of 748  production race bodywork in FibreGlass? just like the stuff he has on the shelf in Carbon Fibre but in slightly cheaper fibre glass, as required by the rules, this would be accurate copies of the road stuff but incorporating an undertray that will collect any oil from an engine blow up, yes he could! Now I started to feel like we had a real racer.

The order went into John in the last week of January, just getting in the queue before the Ally Pally show, we took delivery four weeks later. As anyone who has indulged in the annual 'lets not do any thing until after Christmas' planning system that is the lot of most racers, to get anything done in that timescale is bloody brilliant. Fuel tanks for 748's are over 1,000 so a second hand tank for 150 out of the back pages of MCN was also most welcome.

Sport Production - air pump efficiency

The Sport Production rules letting 750 twins out with the 600 fours brings the UK into line with the World Supersport series.  NOT FAIR I can hear people cry.  Well I guess it depends upon your view of how an engine makes power.

The Supersport and Superbike system is based on the amount of air an engine breathes, ie its capacity multiplied by the maximum revs, divide by two, ('cos it's a four stroke) and divide by 60 to get the volume of mixture passing through an engine per second.

On my reckoning a Yam R6 gets the vote as the biggest breathing engine in the class thanks to its stratospheric 15500 rpm Redline. In second is our 748, closely followed by the ZX-R6 and the Honda CB600 F4.

This formula is quite interesting when applied to the Superbike class and brings home the importance of designing an engine for revs as well as just size.

There are some other side effects, because the relationship between Horsepower and torque is a simple mathematical formula
(hp = torque X rpm )
             5252

There is an apparent advantage to the bigger engine in terms of torque.

The other effect is that, all other things being equal, the smaller engine will be able to spin harder and therefore, in terms of revs, will have a wider powerband.

This was something which helped the Ducati Supermono lap so quickly last year, having the smallest capacity and highest revving engine in the SuperMono class.

This year the boot will be on the other foot. 

Two days after we got hold of the bike it was coming apart. While we will not be doing many miles in the year, it still makes sense to ensure everything is built exactly right. A year with the Ducati Supermono had taught us a few important lessons and we decided there was going to be a lot less uncertainty if we built and checked everything ourselves. Events would prove this was largely unnecessary but starting with a pile of bits and getting really familiar with all aspects of the machine is a habit you get into after a few years racing.

There is a lot to getting an undertaking like this underway, first you need a marathon rule reading session, then setting out a list of things to do, though much smaller than a Supersport effort (and much, much less than a Supermono effort) the resulting list is still way too long. The first thing I did was to speak to everyone I knew with 748 racing experience, not many people it has to be said, to get as many ideas as possible. 

The main bits of bike you can change in Sport Production are bits of the suspension, the bodywork, the tailpipes and jetting (or in the case of the Ducati the Eprom chip in the Weber fuel injection system). Concentrating on the Suspension side of things it rapidly became obvious that most people thought the standard suspension was pretty good, the bike comes with an Ohlins damper on the back and upside down Showa's on the front. The bikes standard chassis also includes adjustments for the angle of the headstock and ride height.   After a few phone calls I found myself speaking to Ken Somerton and Lester Harris and getting hold of a job lot of front and rear springs to give us something to try in practice.

The rulebook uses the same wording for a lot of sections for Sport Production and Supersport so, after a long chat with Barry Hibbert (the man who must have the most thankless task in motorcycling, being Series Scrutineer for a production race series) a phone call went into that maestro of aftermarket bodywork John Merrill of QB Carbon. Could he make a couple of sets of 748  production race bodywork in FibreGlass? just like the stuff he has on the shelf in Carbon Fibre but in slightly cheaper fibre glass, as required by the rules, this would be accurate copies of the road stuff but incorporating an undertray that will collect any oil from an engine blow up, yes he could! Now I started to feel like we had a real racer.

The order went into John in the last week of January, just getting in the queue before the Ally Pally show, we took delivery four weeks later. As anyone who has indulged in the annual 'lets not do any thing until after Christmas' planning system that is the lot of most racers, to get anything done in that timescale is bloody brilliant.  Fuel tanks for 748's are over 1,000 so a second hand tank for 150 out of the back pages of MCN was also most welcome.

Our next priority was getting the engine built, put together with a record of all the clearances and shims as well as a careful check of the cam timing, squish clearances and throttle settings. We went right through the engine, and very impressive it was as well, pistons and barrell's came already sized to each other, metal to metal crankcase joints, the lot (the Biposto models have thin paper gaskets between the cranckases, guaranteeing it is oil tight, but giving a little away in the strength stakes).  We tightened the crankshaft end float a little, loosened one of the gearbox shafts and carefully reassembled the bottom end. Doing this is OK but there is one thing about Ducati's, if you are doing it right you need a binload of special tools!

The list of things to do still stretched out before us, the engine was put back in the chassis, the injection system set up exactly to the manual, no plus or minus tolerances here, and we went off to the dyno to see what sort of power we had.

Dynojet Dyno's are now the industry standard, a 'Dynojet Horsepower' now has more meaning in any conversation on power than any other sort, so we sat on HM's dyno in Green Street Green running the engine in, four fifteen minute sessions, with a cool down in the middle. To complete the abuse a full 20 hard runs through the full rev range followed to ensure the rings bedded in properly, all in all 102 hp with more to follow as the engine loosens up.  This is not the sort of abuse you would heap on a bike you are going to do 100,000 miles on, it is the sort of treatment that you would give a racer, ring seal, and valve seal is the most important thing in an engine. In a class where so little preparation is allowed it is arguable that effective ring seal is about the only thing we can depend on.

Home again after the dyno we dropped out the oil, checked the valve clearances and the belt tension, all the bedding in we could hope for, the belts had loosened a little.  All the valves were sitting in the middle of their adjustment range, mostly between .12 and .17 mm opening and closing (don't forget we have both opening and closing rockers on Ducati's unique desmodromic valve control system). Our target is to run all the valves at .15mm, both opening and closing but we will not check them again until we have done a few more hours running.

The shopping list continues to grow, spare handle bars and handle bar furniture (master cylinders and levers, switch gear and grips, everything you would wipe off in a crash), the production rules mean you need spares. Spare wheels, one front and two rear, can we afford another set? not now but it would be great to have a spare set ready to fit with different tyre choices.

Money continues to pour out for stands, exhausts, Eproms; stronger clutch parts, a selection of sprockets and chains. Then there are the new brake lines, pads and most importantly good tyres.  From our previous adventures we can get to a van, tyre warmers, generators and awnings, this is for a production series!

The chassis and its components need some general loosening up so a practice session was booked at Lydden, the only place we could get to on a Saturday at very short notice! The problem was getting a Rider, Elliott had got a deal to get his truck painted and needed to be there to help out, he could also get the fairings painted, this was not to be sneezed at given the enormity of the bills so far, so at two days notice I get my racing (sic) licence resurrected for a peaceful 75 laps of Lydden.  It took a week before I could pick up a pint properly after that.

With the bike checked over again we fit the body work and decide on the paint job, Elliott is getting his truck painted the same Ducati Yellow as the bike so he drags off everything for its paint, it takes just four days and all comes back, at one o'clock in the Thursday morning. There is just a few days to decide on initial spring choices and work out how to get everything to Donington for our first practice session.  In an effort to speed the learning curve Scott Smart has agreed to take his reputation in his hands and try the bike out for us and give us an opinion based on his Alstare experience.

Donington dawned (literally, we set off at 4.30 am) wet and overcast, we waited until lunchtime and sent Elliott out for a few laps. We are immediately into different damping positions and oil levels, the bakes are brilliant and the gearing is changed.  Ride height comes in for some attention and after Scott does a few laps we knock it on the head. The bike now has four and a half hours running on it, fairly quick running at that. In true race fashion we check the belts, the valve clearances and change the oil, everything looks good.  Four days later we are at a very crowded Mallory park, again we get some basic ideas on gearing and change fork positions and spring rates, the bike is getting more accurate, apart from some unsettling jumps as it hits the bump going into Gerards (they really should bank that corner!) it seems pretty good.

Cadwell is next, a practice day and the first race, its going to be cold and wet, I just know it.

                       Neil Spalding

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