I thought some members may be interested in a carburetor conversion I have just done on my 1973 Tornado. I did it because I found the standard carb springs too heavy and I wanted something that was easy to balance plus being a little more economical. I bought two BING carbs which were fitted as standard to a Ducati Aluzurra 650. They are CV carbs with very light throttle plates. I turned up a circular discs to mount Suzuki GN 250 rubber inlet stubs onto. These take the BING carbs perfectly. The plate is mounted to the old carb stubs on the cylinder. Within the GN manifolds there is an additional small alloy cone to transition the larger Bing carb throat to the Benelli inlet tract. I used a circa 1970's Triumph Bonneville throttle and 1 into 2 throttle cable with the metal splitter/junction box. The plastic splitter box does not have sufficient throw for the Bing carbs. Cable lengths were adjusted and brass nipples made to suit the Bing carbs. A couple of hours work. GN 250 air box tubes also fit onto the rear of the carbs. These were cut down and short cut down foam sock filters added with cable ties. The carbs fit under the tank almost perfectly. It only needed lifting back and front slightly. Not sufficient room for choke cables so I made up a brass lever to attach to one carb and just use it manually. The left hand casing where the starter motor fits needs a small grove filed into it. This enables the brass screw that fits into the base of the carb to fit. Otherwise the carb would sit too high and would not be centered correctly. There is plenty of alloy there but yes you will have to "damage" the casing as such. Since I will never go back to the stock carbs that didn't really worry me. It seems to start OK just choking one side. One thing that had to be done was to change the cable pull on the left carb to the opposite side. This is needed for clearance. I had a shop do this and since everything on the Bing's are symetrical it is quite easy to do. I have kept all the jetting the same and it started right up and ran strong from the start. Still have to set the tick over correctly. It is very easy to balance them manually since the throttle plate axle bolts protrude. By putting a cardboard pointers on then you can look across the bike under the tank and synch them real easy. Anyone wanting further details/ pics please e mail me on [email protected]
Last edited by NZGlyn; 09-12-2013 at 05:01 AM.