swooshdave wrote:frankdamp wrote:I spent the last 8 months of my N-V career working on the Stormer program. Two things to watch for, if they hadn't been fixed in your model year are problems with localized overheating which damages the cylinder liner and frame cracking inmmediately aft of the headstock stiffener (if yours doesn't have the tapered top tube). Taking a closer look at your full-bike photo, what appears to be a weld line along the center of the top tube suggests you have the tapered set-up. Your bike is dated four years after I left for America. The "new" ones being built in a chcken shed were built by one of the retired Moto-cross mechanics from parts he'd bought when the company went broke. if you go to the AJS Owners news group there's some info on him.
The engine overheat was a part-throttle detonation issue. The Starmaker woud run WOT for days without complaint, but in stop & go, light throttle settings, the liner would get red hot around the area of the exhaust port and you'd get instantanous welding of the top piston ring as it passed by. This would set up an oscillation as the piston travelled on and circumferntial ripples would develop. Initially, we would see this in less than 1000 miles on a new liner. I tested the bike riding to and from work on one that had lights.
Initially the fix was to use Castrol "R" in the fuel, but it doesn't dissolve in gasoline, being a vegetable-based oil. After about 6 hours of not being run, you had to give the bike a good shaking to re-mix the gas and oil. As I left (June '68) they were working on a more user-friendly fix.
The early M-X bikes had frequent frame failures caused by a stress raiser where the original design of heastock reinforcement ended. I propsed splitting the top tube into two semi-circular pieces and welding a long triangular piece of flat steel in between on each side. the resulting top tube went from being an obround cross-section almost the full depth of the headstock down to the original circular section at the back. I think this made it into production.
One of the cleverest bits of design on the bike was the eccentric plate for chain adjustment, It shows very well in your pic of the gearbox. I've since seen an identical set-up on (I think) a KTM, so maybe the AJS design was sold off when N-V went Tango Uniform.
I was waiting for you to chime in with your experiences.
I'm sure with a modern two-stroke oil like Royal Purple the overheating issue should be minimized.
Didn't they also use the eccentric adjuster on the B50?
Rohan wrote:Cheesy wrote:
I wouldnt bet on new oils being better,
I would. Engine seizure in GP125 and GP250 racing is almost unknown these days - although the engines are watercooled. And producing beyond 400 bhp/litre.
ajstormer wrote:It handles well - but the engine is so tempremental - dont stall it , it will NOT hot start
frankdamp wrote:The frame in the Sprite photo isn't the AJS frame.
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