BS friends:
The way I remember is the beautiful BS 100 and 175 racers were really only useable for flat track racing. While they had the most powerful engines, the 100 was really limited by the 4 speed and poor shifting. The SR 175 faired better but was very heavy compared to say the Bultaco. Sad to say both the BS racers have
VERY poor suspension even by 1960 standards, the forks, shocks and frame kept the powerful cool racers to the flat tracks, all the time America was going Scrambles and Motocross. The SR100's frame would just fall apart on rough sections of most any off road track. Remember seeing the 100SR engines installed in VanTech and Hodaka frames, really performed much better. BTW: VanTech made a complete bike kit , just install your BS SR100 engine. I raced a prototype SR100 in a frame provide by Champion, in a Hare Scrambles, Was a really fast bike great handling but the darn 4 speed trans kept holding it back. It really needed a slick 5 or 6 speed such as the SACHS had, and modern frame gear.
But the SR100 could win most any beauty contest! Just my 2 cents worth Richard Clark
Here is a video of Gary Toomers restored SR100 and SR175 racers
Here is a photo of a VanTech BS 100 that is on the web, note poor air cleaner modification on this example,
[attachment deleted by admin]