R60/2 Differential Timing

[Rodolfo850]

Hello friends,

I was dealing with some problems to set static and dynamic timing on my R60/2 1969, nothing seems to have sense, but moving ignition point CW and CCW gives almost same result.

Magneto static timing its perfect center on V notch, point set to 0.4 mm, magneto shaft groove end its in good shape, both springs of advance are new.

I measured lobes on advancer, find wear that for sure are origin of differential timing, measured major diameter, lower diameter and in X shape to measure lobes opening, also has wear on the lobe cylindrical section when points make contact to open. I changed with a used unit I bought years ago, that just have a little but equal wear.

After assembly all together, still have same problem, Ignition time still too advanced, showing S mark on top of engine window, and no more space to move ignition point base plate, also moved magneto to make a test, knowing that if weak spark. same problem.

After reading all my available information sources, like Barringtons, Clymer, Doug Rinckes, Duane´s Site and Vech´s Post, all seems to be ok, but ignition time isn't. Even trying to set points with my Aircraft spruce magneto timing tool, a 6 volts lamp, closed point gap, bigger point gap, I finally found that ignition point gaps varies between revolutions, but without a consistent value.

So a flash of heaven light makes me change ignition point set for a used I have on my workbench (at least 15 years old Bosch brand). After a few minutes make a test and WORKS GREAT!! S mark on middle, starts on first kick, no hesitation and goes until F mark on high rev. After checking the removed set, found that has a weak plastic bushing, and even new diameter has at least 0.1 mm of variation, that causes gap variations between rev and of course ignition Dwell variations.

Learning: Always buy a high quality ignition point set and check gap between revolutions , to avoid differential timing.

[jwonder]

Yes, there are many bad points on the market. I only use Norris now.