A friend has scored a NOS kit horizontal magneto. Sprockets, chain. magneto, ETC. Obvioulsy lots of work needs to be done to the right case to install it. Anybody have any experience with one of these?
a friend of mine is building one and has the chain all set up---i just shot him an email to see if he can post some pics. his is a 52 pan. i sold him the correct right tank with the 3 spigots for the oil
I have the drawing for the Wico (29505-50R) case mods and a sketch of the mounting plate for under the mag if you are interested. Just glancing at the drawing that Panic has, the required modifications are different.
I don't think anyone would design an ignition (or cam) drive with such a small sprocket today. One reason is that the instant load on the teeth, roller axles and bearings/bushings is very high compared to a larger sprocket. 17 teeth is considered the minimum size to control this and should be used when practical. There is also considerable speed variation as each roller climbs the tooth and falls into the root, where the exact spark timing will vary slightly between rotations (about 3.4% for 12 teeth, 15 teeth cuts this to 2.2%, 18 to 1.5%, 22 teeth is 1%) unless the teeth are "clocked" at the exact same rotational position with great accuracy. This is a function of tooth count so it's better with a higher tooth count. For those who'd like to re-invent this, the cam drive chain from anything small could be used including Norton, Honda 360, Yahama 650 etc. The Norton is hardest to find, but with only 18 teeth should be an easy fit. These run roughly 1/4", 7mm, to 8mm pitch. Obviously, the smaller the pitch the smaller the sprocket OD, and the higher the number of teeth for a given OD. As long as the idler gear is twice the pinion gear tooth count (OHV: 42, UL 40, 45 36), and the tooth count on both sprockets on the idler and on the magneto are the same, the timing is correct - no specific sprocket tooth count is needed, although this will change the center distance between the idler gear and the mag body. An OHV idler can be made from either the original ignition drive gear (25850-36) or the 1930-48 VL & UL flathead big twin idler gear (25775-30) by brazing etc. the sprocket itself, or adding a stud so that the sprocket can be keyed in place. This allows offset keys to be used to make small timing adjustments.