RB Racing designed the first successful BMW turbo kit in 1980-1981. The kit employed newly available IHI RH05 Turbochargers that were applicable to motors as small as 750 to 1000cc with a capacity of about 125hp @ 15psi. Previously to this, the only available turbos were larger Rajay units that would not produce any boost until peak rpm.
The RH05 turbo had an integral wastegate that was a rather crude, requiring two 10mm wrenches to make minor adjustments. The turbo resided on top of the motor/transmission using a Keihin Snowmobile carburetor. 38mm primary exhaust tubes were mitered into a 2-1 flanged collector with a 42mm connector tube to the exhaust housing. The exhaust tail section was complicated with a 52mm exit to the rear of the transmission branching into a dual megaphone muffler assembly via a wishbone shaped connector, with all parts done in black chrome. The wishbone connector had to be creased in a press for centerstand clearance.The inlet tract consisted of a "U" shaped 42mm tubular runner connecting the two inlet ports.
Over 300 of these kits were produced with several higher output versions made, capable of about 180hp, one of which was installed in a Rob North monoshock frame that set a 10 second drag racing record. By 1984 sales came to an end and the early RH05 turbo was discontinued. The advent of the K100 at that period ended any further production of these kits. Ten years later in 1995 we threw away the production fixtures and any remaining parts.
The R series were moderately good turbo candidates with their excellent cooling and the fact was that any increase in power was welcome with all the Kawasakis roaming the earth. The ugly side of things were the vagaries of carburetion with long warmups required, flexible frames and swingarms, and detonation under improper fueling and higher boost. Water injection was developed for boost above 5 psi.
More modern turbos with our BoostMaster Wastegate. Intercooling and fuel injection with revised electrical systems. Dual plug heads with special ignition systems. Closed Loop Knock control. Perfect driveability with excellent fuel economy. Optional forged pistons and updated clutches. All of this is possible. The parts are here. The question is always price and the associated R&D. The adaptability to newer models with Nikasil bores and monoshock suspensions is an area to be addressed.