First Honda four, back in 1979.

[Tony.B]

Re Jock Kerr Motorcycle Developments Limited (JKMDL).... I worked there for a short time during my college holidays in the late 1970's.. by this time Jock Kerr had sold up and I THINK he went to work at Eddy Grimstead's motorcycle / Scooter place in North or North East London. The owner, manager, etc when I was at JKMDL was Mike Sturgeon, as far as my memory goes he was a nice boss, had a business plan BUT did not know of the engineering or physics side of things...., engines, metal, heat, lubrication, balance, etc hence there were so many "Issues".. So to clarify things a bit, rocker and camshaft Stellite welding I think it was called, grinding, etc and ALL precision engineering work was done by a neighbouring company called Joy Engineering. At JKMDL we did engine stripping, assessments, rebuilding so the then rebuilt engines could be sold as reconditioned units, that meant your pressed up Honda CB125 single crank if it felt right it went back in, even if the engine had done 30,000 miles, it was only if the mains & big ends had plain bearings that were actually measured, and often only had new shells the surfaces were not re-ground, small ends were rarely touched, valve guides ditto. The balances of failures, returns, refunds were offset by the ability of JKMDL to weasle out of paying up, 'you did not do this' or "that's wear & tear", often asking for the engine to be sent back for assessment then taking ages to assess, often sending out another just as dodgy unit in replacement... The Mods, big bores, smaller capacities were virtually all crap.. The big bores were nearly always overbored standard bore liners so leaving the liners too thin and they cracked where the liner left the bottom of the cylinder casting, the 400/4 to 250/4 sleeving down was just an extra lining put in the standard liners with i think Honda C50 pistons, making the liners too thick to dissipate the heat, ok at start up, ok for short runs but give it some welly or constant 60mph and the pistons would seize... the 250 Superdream conversion to 125cc was a topless piston in one bore with the rockers removed so making it a VERY vibratory 125 single that if it lasted without falling apart from the vibrations it would blow the crank in 500 miles.... The list goes on and on, I only stayed there as I needed the money and I had access to the workshop, my job was on the Honda singles range C50 to CB125 OHV & OHC.... After JKMDL closed the company went onto making rubbish chromed & non-chromed 4-stroke noisey exhausts that often lessened the bikes power and always got you nicked, sold from a shop in I think Market Place or square, Hatfield.. Shame really, the potential was there just not the brains.

Nice insight, thanks for that. Were you the mechanic who came off it road testing it after the bike went back for its conversion back to 400? It cost JK a new tank and Cibie headlight!