B12 Speedfighter Modifications

Suzuki B12 Bandit 1/2" Airbox Mod

The speedfighter had the two inch air box mod carried out which involved cutting a circular hole in the side of the airbox to allow it to flow more air. The main jets are then changed from 112.5's to 127.5's with the needles lifted to their highest position.

This is carried out in conjunction with a can change as the standard Suzuki item is not only very heavy but very restrictive. Fitting a race can gives a considerable boost in power right across the range.

Be aware of the small O rings that seal the vacuum take off pipes on the carb caps to the carb body. They are only about a quarter of an inch across and are easily lost when removing the caps. This will cause a loss of vacuum on top of the diaphram thereby stopping the slides lifting properly which will result in a loss of power from the affected cylinder.

Please dont ask me how I know .... #:0)


Suzuki B12 Bandit 17 Tooth Sprocket Mod

Regarding the fitting of the 17 tooth front sprocket, be aware that a 14 tooth item is the largest that can be fitted without modifying the sprocket cover. The problem is with the rear most bolt which will straddle the teeth of a larger sprocket preventing it turning. The answer is to cut off the lug that the bolt passes through and make a bracket from three pieces of eighth plate weilded together form a bridge over the sprocket. The bracket is then drilled to allow it to be bolted to the engine casing and then drilled and tapped to allow the sprocket cover to be bolted to the bracket. Also, a new standard chain will be found to be too short requiring the adjustment slot  on the swing arm to be milled out slightly. This might not be a problem with a chain that has stretched slightly. 

A 16 tooth will fit with the standard chain