Bultacos In the Offing
BULTACOS IN THE OFFING
Previews Of A New Motocrosser And An Interesting Big-Bore Trials Mount
The new big-bore Bultaco trialer features an 83.2mm bore and 60mm stroke for a total displacement of 326cc. At this time, compression ratio is being adjusted for best overall performance. Possibly due to the very oversquare cylinder dimensions, there is a tendency for the engine to become confused about which direction it should be running, and stalling can easily occur. Further work with flywheel weight, ignition timing and compression ratio will eliminate the problem. Developing 17 brake horsepower maximum, the 325 is about three horses stronger than its 250 counterpart, and through the whole power band, which is the only thing that counts in trials. Acceleration is brisk from the very bottom of the rpm band, and hard throttle can be used without fear of looping the plot. It is possible that, after opinions from four of the world's best trials riders during the very difficult San Antonio trials, the engine may be moved one inch to the rear. Both Sammy and Ignacio prefer a delicately light front end, whereas / found riding Sammy's bike was great because of the ease by which it could be handled by a non-expert rider. CYCLE WORLD will feature a test of the large Bui as soon as its design is finalized.
Gary Bailey tried the new Bultaco 400 motocrosser during our trip to Spain. The new 85 by 70mm engine displaces 397cc. At this point, and with only initial engine development, the engine is producing 40 brake horsepower, but is very tractable. Bailey was impressed with the wide power band and the willingness of the engine to bog down and recover. He feels the bike is a winner in its present form, but Mr. Bulto thinks that a little more work should be done on the power band to obtain maximum power without sacrificing tractability. There are no weight figures at this time. The machine we saw was a mule for developement purposes, and the real production model will be lighter. You can bet your boots, though, that the big Bui is going to be something scary.
