Scootering, number 94, July 1993 - Rob Miller's MB200 group 4 Lambretta Racer

Rob Miller is a grand old man in his forties. He started racing late in life - 11 years ago.

To start with, he competed in Group 4 (Standard 200) and then both Group 4 and Group 6 (250 Specials) only to drop out of Group 6 to concentrate on Group 4, which he did for five years, only to gain a few second places.
In 1992 MB Developments were looking for a rider to accompany Graham Gee's success in Group 6. Group 4 seemed to be the class that scooter dealers went for Dave Webster (MSC), Malc Anderson (MSC), Martin Cook (Chiselspeed), Keith Terry (Kegra), Ralph Saxelby (R S Tuning), Bob West (Taffspeed), Pete Merchant and many more. As you can see, famous names of recent years, and just the group to make an impression on in business terms.
Rob Miller's name came up in conversation, so I made myself known to Rob, having never met, and he welcomed the help offered!
Duly a cylinder kit was supplied and with Rob's hard riding and tuning by myself, Rob gained some instant success - enough success to prompt Rob having a full scooter and engine rebuilt by myself to start the '92 season - the aim to become Group 4 Champion! From development work gained from road motors an engine was built using a Honda 205 cylinder kit as per road conversion.
To start the season it was a bit hit-and-miss - lots of problems. The motor smashed flywheels, cranks and ignitions. The unreliability was embarrassing but between all this Rob picked up a few wins! Racing was close and there was nothing between the bikes racing.
Further developments took place on Rob's engine. A new cylinder proved to be so much quicker destroying the clutch (this hadn't been a problem to date!). A 6-plate clutch was fitted, which cured the problem.
Suddenly Rob led the field from start to finish, then other problems occurred - missed gears and overrevving wrecked pistons and con rods on a number of occasions. Rob pulled out of races many times whilst leading races with silly faults and falling off when racing too hard. Rob is hard on both engine, bike and himself, making exciting viewing at times.
By the end of '92 Rob didn't manage to win the Championship but came third. The points system doesn't pay to win; it pays to finish and you gain a better position overall - well, that's racing! Not to be deterred Rob entered 1993 heading a new team 'Team MB'.
The '93 season looks promising for Rob, but business ties and family pressure could mean this is his last attempt at the championship. This year new rules allowed a non standard con rod to be used in the standard classes - about time! This was Rob's weak link.
For '93 a new engine was designed around last year's port timings; a change of piston to Suzuki; change of rod to Rotax; change of ignition to Honda; with a one-off exhaust and gearbox with the usual 6-plate clutch and 34mm smooth bore.
The engine has had some early faults but have been weeded out after the first few races. Rob has led many races, falling in a few, coming second in two and winning the rest!
The quality of racing in Group 4 is the best for years, with Malc Anderson and Bob West being his main rivals, with all three pushing each other beyond their normal racing limits. One small mistake loses the race.
Further development work has taken place on Rob's handling and is beginning to improve his riding ability. To date Rob has won 14 and taken 8 seconds since the 1992 season. It would be a shame if he drops out after this season, winning or losing the championship! Rob gives a lot to the sport, regularly helping other racers on weekends, midweek and at night, as well as attending LCGB rallies. Rob still finds time to support new race members and is a valuable member to Team MB. (There is no wonder his other half gives him grief)!
This is the first year of Team MB made up from riders using engines by MB Developments. Other riders include Eddie Goode competing in three classes non-stop on a 125 Vespa; Steve Hamilton returning after 4 years off in Group 5; Shaun Hodgkin, and Mike Davis who had dominated Group 6 in both FBSC and NSSA events on a MB Developments prepared motor.

The dyno test shows the type of power that the MB200 Standard Group 4 motor produces from 4,000 rpm at 5 hp. It sharply accelerates to 25 hp and holds power over a wide rev range from 7,500 rpm to 11,000 rpm. Although there is still room for improvement, I believe this to be an engine very difficult to improve. A rev counter might help Rob!
Rob is now to enter Group 6 as well and should prove to give them a run for their money, so good luck to Rob and Team MB.

Mark Broadhurst visibly being thrown forward as he slows down from nearly 90mph and tries to avoid hitting the wall.

HERE'S WHAT YOU CAN DO WITH YOUR STANDARD GP 200

FBSC's long standing Groups 1, 2, 3 & 4, and the NSSA Standards Class regulations are aimed specifically at racing scooters in pretty much their original formats. The bodywork must resemble that of a standard scooter and the engines must retain their original form of induction, i.e. piston ported for Lambrettas and rotary disc for Vespas. Reed valves, kit barrels and crankcase welding are all banned in order to restrict the modifications to a sensible level and make the racing closer by making the tuners do the best they can with pretty much what they are given.
It hasn't worked that way entirely as shop prepared and sponsored machines are the only ones in contention particularly in Group 4, the 200cc class where the top machines run expensive advance/retard ignitions etc. Rob Miller's race bike is one such machine, but apart from a few fancy parts such as Hitachi ignition and a 6-plate clutch conversion, it is surprising how closely related it still is to a road machine. Just look at the specification below.
Frame: GP 150 (lower headset height).
Forks: GP200 standard springs, double thickness fork link stops, Kawasaki steering damper conversion.
Headset: SX200 (lower bars than GP headset).
Bodywork: All metal GP apart from fibreglass mudguard.
Front brake: Home converted hydraulic disc operated by Kawasaki AR master cylinder.
Tyres: Dry - Michelin S1 (yes, the same as come standard on Vespas now); Wet Bridgestone or Yokohama.
Engine casing: Italian 200 with Li Series I/II engine mounts.
Gearbox: Li 150 Italian with 14/48 sprockets.
Crank: Indian (?) GP200 with Rotax con rod conversion.
Barrel: GP200 with 3 whole days of porting work.
Manifold: MRB 34mm smooth bore.
Carb: Amal 34mm smooth bore.
Exhaust: One-off, fully blown (race £150, road £180).
Piston: Suzuki RM250, single ring type.
Clutch: 6-plate conversion.
Ignition: Hitachi auto advance/retard.
Rear shock: Bitubo gas adjustable.
As you can see, it's not all that special parts-wise; no fancy gearbox, no special frame or forks, even the back brake is still in the original position, but it wins races. Why? Well, partly due to Rob's riding, of course, but also because it makes 25 horsepower, and a fat wide spread usable 25 horsepower at that. Look at the power graphs above. This is the most powerful piston ported Lambretta we have ever tested - it's only 205cc and yet it's making more than double the original horsepower. Some going!
Again, this machine, like many others we have dyno'd, has been tuned by Doncaster ace Marc Broadhurst. If you are getting sick of hearing about him, then tough!

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