The gift that keeps on giving…

It has been exactly a month since I took delivery of the SB2. Investigating the history has been what I can only describe as a roller coaster ride. Information just keeps on coming in and it is both wonderful and fascinating. I put a post on the Facebook ‘Bimota UK FB page’ asking if anyone knew any information on the Bill Smith 1978 TT F1 SB2 bike. This was before I had made contact with Bill himself. To my surprise, I receive an email to my work address, from Bimota enthusiast Fedor van de Pol who is not on Facebook but had come across the post. He had written a research piece on this very bike merely a year ago. The conclusion to the fantastic article he wrote says “Unfortunately it is unknown what became of the Bimota Suzuki SB2 chassis that took part in the 1978 TT Formula 1.”

Bill Smith at Governor’s Bridge IOM TT 1978. Photo Source: Paolo Girotti, Facebook.

His piece included many wonderful photos but has never been published due to potential copyright issues with the pictures. Without the photos the article would lose much of its impact. It did point me to some pictures that I hadn’t previously seen that were in the public domain as well as the ones that weren’t.

Bill Smith at Greeba IOM TT 1978. Photo Source: Barry Gollings, Facebook.

Of particular interest, was something I hadn’t previously noticed about the TT bike. With Bill being old school British and weaned on right foot gearshift, this bike had been converted so that the brake pedal and gearchange were on opposite sides.

This was incredibly interesting because it explained some damage that I had found on the underside of my frame which at the time of discovery I couldn’t understand how it could have happened.

The brake pedal is a long way away from the damage point. Note the indent features on all SB2’s, the scratches to the finish are from the crossover rod.

The brake pedal was quite a way from the point of damage and could not have caused it. A close up image of the SB2 in Silverstone trim, reveals the gearchange setup on the right…

A close up of the SB2 in Silverstone trim. Note the gear lever location and the strap fastened around the chassis bar holding the bodywork down.

I imagine that this setup employed a cross over rod. From research I learn that many other SB2 ‘s feature the ‘relieved’ section in the Chromoly chassis tube. It would not surprise me in the least if Tamburini incorporated this by design given his racing chassis design background. Either way, the siting of the gear changer is exactly where the marks occur on the chassis and the marks bear testimony to this day to the right hand shift.

Note the paint flaking where the Axle stand and bar setup was used in the paddock in its racing days.

I’m grateful that the chassis has never been refurbished and is totally original, having these tell tale signs 43 years later, perfectly corroborates the provenance of this machine.

There is further evidence of it’s racing days also. In race trim, the bodywork was fastened down with straps wrapped around the tubular chassis bars.

Note the fastening straps around the chassis wrapping around the base of the seat/tank. Also note the auxiliary tank with filler cap placed on top of the rear tail unit, painted red with a ‘Champion’ decal.
The left hand chassis bar showing evidence of the use of straps to secure the bodywork.

Straps marks are still visible to the chassis. These rubbing marks only occur at this point, the rest of the chassis bars are unmarked.

The right hand side strap marks.

The right hand side also has corresponding marks where the straps were positioned.

With the rear brake reservoir relocated on its proprietary bracket but on the opposite side now, there is evidence where the mounting bolts for this would have come into contact lightly with the swingarm, likely under compression.

With the tail now removed from the bike and carefully laid on the garage floor, I can now take proper photos of the modified fuel system on this SB2. Below is a reference photo sent to me by a fellow SB2 owner. It shows how the fuel system should have looked…or not…because the one piece main tank with incorporated saddle tanks is totally encased in fibreglass and invisible. You can notice where the rear tyre has contacted with the tail unit and it shows how thick the original tail unit is.

The tail unit of a standard SB2.

This unit would have housed a one piece fuel tank made in aluminium and shaped to include the saddle tanks on either side as a single unit.

The standard tank unit which would be contained and encased in fibreglass within a standard tail unit.
Bimota operative Dervis Macrelli (described by Motorcyclist online as a frame making wizard) preparing the one piece tank/seat unit. Note the metal tank standing up on the far right and the metal seat hump support on the table in between the two seat units. It is purported that Bimota lost money on each SB2 hence the subsequent later SB2 80 and SB3’s had the more simplistic and conventional rear subframes and bodywork.

This is the fuel system on SB2 #094

Note the hollowed out rear wheel well. This material is far thinner than the stock item. Perhaps to both reduce weight and provide more tyre clearance.

The whole underside is modified from the base of the main tank to the separated saddle tanks that are now detached and incorporate balance pipes at the front and rear between them.

Note the crossover balance pipe array where the saddle tanks join the main tank. Evidence of some fabulous welding around the fuel tap.

The standard tank unit has an inherent weakness where the fuel tank can split at the point that the saddle tanks meet the main unit.

A close up of the fuel pipe arra

By separating the tanks, any flex will not result in a cracked fuel tank while the balance pipes are connecting the saddle tanks to the opposing sumps on the main tank unit.

Cross over balance pipes in the rear clam. This pipework would feed the main tank with fuel from the auxiliary tank, The tape most likely protected the hose where it exited the bodywork, for which there are signs of a repair to this area.

In the rear of the tail there are further crossover balance pipes between the saddle tanks. The additional hose that is tee’d in tucks down into the depths of the seat unit but it leads nowhere.

The open pipe would have been connected to a fuel tap on the TT trim bike. How I wish the auxiliary tank was still about!!

I retrieve it and confirm that it is completely open. Blowing compressed air down it send the air straight out of the breather at the front of the main fuel tank.

The auxiliary tank can be seen on the tail of the TT bike, sporting a Champion sponsor decal.

This would have transferred fuel from the tail mounted auxiliary tank and fed it into the saddle tanks back in the day. There is black tape wrapped around the hose still where it would have exited the bodywork.

By another happy coincidence, another line of enquiry on the Bimota forum asking about ‘Galleria Bimota’ in Cranleigh who were the importers in the 90’s and who sold this ex Dixon bike in 1997, yields an unexpected response.

Enter Colin Charles into the frame. Colin was the workshop manager for Dixons Racing in the late 70’s until the 80’s. He built all of the Dixon Bimotas including the Elvington title winning SB2/80 and SB3 and….. worked on an SB2 race bike for TT rider Bill Smith!!

Colin has the most time enduring archive of all time, hand written notes that he has kept to this day. He is able to provide a whole new angle of information and some fascinating insight as well as sharing some wonderful experiences.

I learn from Colin that the bike was sold to Bill Smith on the 15th May 1978. It had the special Yoshimura engine which his notes say was 944cc but he is sure that it was 984cc. The engine was over bored and had a stroked crankshaft. After it blew up (at the TT) the crankshaft was shot and fitted with a standard crank making it 944cc. The bike was converted to r/h gearchange and l/h brake. Colin had just joined Dixon Racing and did not have anything to do with the bike until later.

His detailed entries included information of when and where it raced and other notes;

25th May 1978, practice at Oulton Park, front brake leaked, seat/tank cracked.

Bob White (Suzuki Chester) prepared the bike for IOM.

3rd June 1978 IOM F1 TT race, failed after 1 1/2 laps as No.17.

Mike Hailwood (No.12 Ducati) at the 1978 TT, Bill’s Bimota SB2 (No.17) in the background

1978 Ulster GP practice, fastest lap in practice at 168mph.

Ulster GP 1978 programme, Bill would have run under the No.8 but it was not meant to be…

Crankshaft snapped, did not race.

Extract from the Dixon Racing catalogue. The SB2 sporting the No.6 this time in Silverstone trim.

Silverstone GP raced but problem with front brake, finished 10th.

Mike Hailwood at the Silverstone GP, once again, Bill on his SB2 is poking its front wheel into the picture right behind Hailwood on the grid.

Brands Hatch 28th October 1978 raced by Bob Smith (no relation) finished 12th after a bad ride.

Although the Programme shows Bill Smith as the entrant, Bob must have taken his place after the programme was printed. According to Colin’s notes it was Bob Smith racing on the No.162 bike.

The race engine from this bike was subsequently fitted to the Dixon Racing record setting Elvington SB2/80 road bike so they could continue their development.

Extract from Dixon Racing catalogue.

I understand from Colin that Yoshimura ran the engines very highly strung, the idea being that it only needed to hold together long enough to finish a race, twice it didn’t, although as reported by Bill Smith, it was a very fast bike and in fact the bike that came second to Mike Hailwood at the TT was John Williams on bike No.16, who in that TT was running first on the road, both Tom Herron No.18 in second and Bill No.17 in third had gained on him in the first lap alone demonstrating the available pace and hinting what could have been if the cam chain tensioner hadn’t failed in that race taking the crank with it!

Tom Herron’s Mocheck Honda also failed in the race.

Tom Herron No.18 Mocheck Honda and Bill Smith No.17 Dixon Racing Yoshimura Bimota Suzuki SB2 on the starting grid preparing for take off…

Colin later detuned the engine a little for reliability while still setting the Elvington records and the old SB2/80 is still around to this day. Bill’s bike was subsequently fitted with the Dixon Racing upgraded Yoshimura 850cc GS750 engine and Lockhart oil cooler as fitted to the other fully optioned Dixon customer bikes.

Yoshimura 850cc engine kit for GS750 engine. (Extract Dixon Racing catalogue)
Optional Mikuni smoothbore carbs (Extract Dixon Racing catalogue)

Given the frequency with which the highly strung Yoshimura engine was failing, I’m perhaps grateful that a less highly strung lower maintenance unit was installed, complete with the Mikuni Super carbs.

Extract from the Yoshimura Tuning Catalogue showing the Yoshimura 850cc equipped GS750 Powergraph corresponding to the current as fitted Engine peaking at 100.46HP@10,500rpm..

Once again, the quality of information available for something that occured over 40 years ago continues to astound me and that is testament to the passion and dedication of those involved. For this latest update, I owe a special thanks to long time Bimota enthusiast Fedor van de Pol and Colin Charles (ex Dixon Racing) for reaching out to a post on the Bimota Forum. Thank you both so much for the information, interest and support you have provided on this rollercoaster journey.