71 BW HS40 engine

Mini Bike & Go-Kart Parts

As far as I know, the 1971 HS40 does not use the big lobe MCR cam, but the previous year (1970) did. One of the more serious guys will probably be able to elaborate.


Well-Known Member
Tag is pretty rough but looks to read 55350C
Thats not a Number that Rupp used on anything, its a standard (non slanted) bushing crankshaft number......it is a mini bike used though it appears, but I kinda quite going down the line once I saw the crankshaft number .;)

Hopefully your just seeing it incorrectly and its a 55330C That is an early 1971 enduro/hustler/blackwidow used engine, which was a standard intake/diaphragm carb, earlier bolt together throttle (like you repro) when they went into the Rupp facility at least, coming out of there if bolted on a BW some of those parts were of course were removed to fit the dell.

I do think that it is the earliest # for 1971, But there was a 55330B number I found, Its probably a 1970 Enduro engine, but I cannot verify. At any Rate in this case if it is in fact a C revision number it is a standard "BCR" fixed/bump compression release engine, The B in that engine # code was the Mechanical unit.