Turbo CBX
Date: Monday, October 27 @ 09:14:00 EST
Topic: News

As our friend Mark Miller has known for some time now,
turbocharging a Honda CBX can provide an exhiliarating ride.

German drag-racer Andreas Fuhrmann was thinking along the same lines, when he conceived the idea of taking a stock CBX and add “a few extras”. Based on his drag-racing experience, he decided to mount a turbo-charger to the six cylinder engine. Of course, it wasn’t as easy as “slapping on” a turbine. Consideration had to be given to the substantial amount of masses which move back and forth and up and down in the powerplant. If additionally loaded with a fair amount of boost, the stock components will eventually “sign off”, as Fuhrmann experienced with his CBX dragster, that spew its connecting rods. As CBX engine components don’t grow on trees, he manufactured his own connecting rods out of titanium. The engine block was replaced with a cast big-bore unit which increased the displacement to 1232cc and provides improved structural integrity. Pistons for the 70mm bore were provided by specialist Wahl. Only changes in the cylinder head were made by installing slightly larger valves and stiffer springs. Crank, cams and tranny remained stock!

The clutch, however, received some support to be able to manage the increase in horsepower and torque. The heart of the modification is the Rayjay turbocharger. It works according to the “wet charge” method and obtains the fresh load through a mighty 47 S&S carburetor and blows the originally 105 horsepower to an impressive 220 using a boost of 10 PSI. Possible could be about 15 PSI which would produce some 270 hp. To prevent the cylinder head lifting from the block, compression ratio was reduced from 9.3 to 8.7:1. Final drive ratio limits top-speed to about 125 mph, which again helps acceleration. Extended high-speed excursions are not necessarily desired and chassis mods are limited. Wilbers shocks in the rear and a White Power fork in the front together with a Fischer swing-arm and modular wheels from the same manufacturer put the performance on the road.

It was decided against a 240 rear tire on the 6” wheel, which would have required a frame change as a track offset would not have been acceptable to the builder. A rather “cool” feature is the hole in the tank which provides airflow to the turbo during the ride and keeps the temperature down. Keeping the perfect paint job in the original color scheme adds an extremely nice touch. Total cost to build was approx. 20,000 Euro.
Unfortunately the turbo kit consisting of turbine, intake and exhaust manifolds is no longer available, but Fuhrmann is supposedly in negotiations with the manufacturer of the mufflers, Schüle to come up with a revival kit

This article comes from Honda CBX Motorcycle World

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