by ffkiwi » Thu Feb 06, 2014 9:43 pm
Howard-I've just checked two of my RI ones (the FI ones are in models and I'm not going to dig them out)-both have the piston skirt ports (and matching ports in the liner). Now developing this theme a bit further-IIRC the first model was the series 67 which I'm pretty sure had a cast head, followed by the series 69, 70 and 71-all of which had minor detail changes-machined head, PTFE gudgeon pin pads etc. Somewhere along the line the design morphed into the model 4011 K&B 40-and in turn various derivatives. The 'metric' schneurle K&Bs emerged from 1972 onwards-but the crossflow 40 (and 61) remained in production alongside, once again going through minor detail changes-carbs, Perry pumps etc. Somewhere in this continuum K&B stopped (or their supplier stopped) shot blasting the crankcases-and they then appeared more silvery-but rougher surfaced.
Numbers I think came and went as a matter of company policy-all the early greenhead series seem to have them, and the 'schneurles'-but not all the mass production models such as the 40 and Sportster series......
ChrisM
'ffkiwi'