Special Branch
 

CLICK ON THE IMAGES TO OPEN A HIGH QUALITY VERSION IN A NEW WINDOW

 


THE name Branch is synonymous with drag racing, father and engineer Dave campaigned an MGB car engined bike in the 70's and 80's. Now he is crew chief and builder of the 'Special Branch' Funny Bike ridden by his son, thatcher Shaun Branch.

The thing that sets this Funny Bike apart from all others, certainly in Europe, is that it is supercharged and runs on methanol. For the spectator this makes it technically interesting, better still it sounds fantastic. Very noisy in an nasty, angry sort of way sums it up for me.

  

 

Resting on its frame rails after a good thrashing
Special Branch poses at Avon Park 2002
(No larger image)

 
 

HAVING run a turbo Kawasaki Funny, the team planned to go Top Fuel racing. A Sprintex supercharger was purchased and work began on the crank before the project was abandoned and work began on 'Special Branch'. All engineering work was undertaken by Dave Branch Engineering (DBE), including the very carefully thought out frame - a real work art.
This has a detachable top section to allow removal of the engine etc. Also very neat are the front engine mountings which take the form of clamps around the frame tubes, thus aiding engine installation. Having struggled with many an engine myself this can only be a very good thing.
Note also the eccentric chain adjusters which can be used to adjust ride height too.

  

Branch funny bike 1
Note oil catch tank above cam cover

Mounting
 
 

CLICK HERE FOR BIKE SPECIFICATIONS
 
 

THE bike was ready to run in mid 1997 and by the end of the season had run a very encouraging 8.09 @ 166 mph. Bear in mind that having decided to be different to everyone else meant that finding someone to assist with tuning was very difficult.

IT is so easy to glance at a bike like this in the pits and not appreciate the immense amount of midnight oil burnt in its creation and running. For example the mechanical fuel injection is by DBE using an Hilborn pump. The system uses a throttle valve, and fuel bleed components by DBE. These control the amount of fuel from the pressurised system that is returned to the tank, and thus by implication the amount delivered to the injector nozzles.
An interesting component is the Nitrous Oxide solenoid which has served a number of functions; An idle (tickover) lean out to keep the engine hot (methanol burns very cool), and also a high speed lean out during the run. The latter is controlled by an rpm trigger from the datalogger.

WITH advice from a Top Methanol car team, among others, 2002 started with a new personal best of 7.81. As the year progressed it was pretty obvious from a spectators point of view that the bike was launching harder than in previous years, and this was borne out by a stunning 7.23 at the season closing National Finals. This despite a slight ignition problem!

I can't envisage what it must be like to ride a bike like Special Branch, so I asked Shaun if he could explain;

"Acceleration is a funny thing; the first time it scares you, the second time you love it.
Just think of so much acceleration and noise that you feel the bike is out of control, trying to drive out from beneath you, leaving you on the tarmac. Any slight movement and you will be flipped off the back.
"With 5 years experience running the bike, if all goes well its like a ride in the park; you do not even notice the acceleration."

FINALLY exciting news for 2003; a new 'Special Branch' will be under development with a larger supercharger and reversed cylinder head, top fuel style.

  

Throttle body
Fuel system details

 

Drive side

Gauges ahead of cam cover are for air tank pressure and oil pressure. Oil temperature will be added for 2003.

Supercharger drive

 

Top

 

Ready to launch at Avon Park
I prefer not to use action shots*, but couldn't resist this one by Gareth Evans of www.1320.com
Father Dave stands at right with Shaun in stage. The tension is palpable and the only thing missing is that fantastic noise.
 

 

  

* OK I can't take them!