1958 AJS Model 30

[Don Madden]

Alan, I believe the 1958 650cc twins were sold only in the US, mostly in Southern California. I have a copy of the test report than appeared in Cycle magazine in January, 1958, so they must have started production in the previous fall as other models.

The machine, referred to as the "Super Hurrican" was timed at 106.84mph top speed on open road & 14.17sec. in the quarter mile.

The 1958 650cc used the same 7 fin barrels & the heads as the 600cc but with the gudgeon pin located higher in the piston to acommodate the longer stroke.

I have seen many of the G12CS variant which were equiped as other competition models. I have seen two G12 bikes & one model 31 in street trim also, so most must have been the comp version.

I once had a set of crankcases stamped 58/G12. It had the unmachined boss for the 1949-50 type screw in oil pressure relief valve on the timing side half. I have seen a lot of cases from when they moved the valve to the cover joint face, but none had that feature. Seems that using up old, obsolete parts on newer machines was a long standing tradition at the works.

I have seen many 1958 crankcases with escape holes. I think most were due to rod cap failure but I know of a couple of broken crankshafts, too. I suspect it was common to blame rod failure on the crankshaft, adding to the "Broken Crank" image.

Cheers, Don. Edited by - Don Madden on 11 Mar 2008 01:51:07 AM