Ashman tells us his Timing cover mounted JH has been stable for years. This would be an older JH. The newer models with the 4 rare earth super magnets may not be as stable.
In any event, Ashmans timing cover mount should not be compared to a flange mount behind the cylinders.
Slick
Slick my JH on my Norton is the 4 rare earth super magnets and hanging off the timing cover hang out in the cool breeze and runs cool, some may say the heat don't worry them behind the motor and I know lots of the old Lucas mags did suffer some heat problems and whether they do with the JHs mounted behind the motor, I wouldn't know as I always had a timing case mount JHs, maybe that is why they might lose magnetism caused from heat, who knows.
My JH is set at 28 degree full advance when set static, will fire up first kick from doing static timing but if any sign of kick back I just retard it ever so slightly till no kick back as I don't use a timing light, once set right and in over 12 years on my Norton and well over 35K miles on it, it has never kicked back when kicking it, as I say it starts first kick every time and most of the time it fires up even before I get 1/2 way through the kick and that's at full advance.
One thing I know the capacitor should be replaced every few years, JH sell the tune up kit for about $40 comes with new points, capacitor and new copper core plug leads, I have a tune up kit but so far haven't needed to use it yet, while its running good and starting first kick I leave things alone, another thing never clean the points with a points file, if you do the point's will wear out real quick, I just clean mine with a bit of Metho and a bit of rag if it needs cleaning, but so far haven't touch them same as the spark plugs, running good leave them alone, plugs seem to run very clean with a hot spark from the JH.
As you can see in this pic my JH hasn't been touched for a very long time, the timing allen head bolts haven't been touched in over 12 years since it's been mounted and set, I also run a bridge on the plug leads near the cover, this stops the plug lead from popping out off the cover and I only pull the cover off just to check the point's and lube the felt pad for the point's cam, but that has been over 12 months since I done that, I know I have been a bit slack lately.
This is one of my mate's old Triumph Bobber the JH on it has been on that bike for over 25 years now and he has only just changed the points, capacitor and plug leads for the first time in he can't remember how long ago, this is the older JH 2 rare earth maggie but it's not a long distant rider like my old Norton.
But hanging out in the breeze the JHs seem to be very reliable and happy hanging there.
This is a pic of my old 1981 Triumph 650 Thunderbird with my traveling bread box fuel tank with my old 2 rare earth JH I done 250k km on that bike with that JH maggie and only done general maintenance to the maggie in all those km's, that was the most reliable bike I ever owned and still regret selling it to this day, I rode the wheels off that bike.
Ashley
