I've a 50 Panhead with Joe Hunt Magneto; the engine run very well, but in these days I've one problem.
In the past days I've adjusted the pushrods, since to zero clearance, but loose enough you can spin the rod with two fingers.
After that operation the engine doesn 't start with kick starter (cold or hot is the same doesn't start)......... start only by "jump-start" or down the street.....
When start, the engine runs very well...............
Your clutch transmits your kicking power to the crankshaft. If your clutch has any slippage in it all, the amount of rotation your crankshaft recieves during kicking will be GREATLY reduced. And your little magneto will not spin over FAST enough to generate a spark strong enough to light the engine off.
When you get a pop start, you are spinning the engine over faster than you would during kicking ( or at least as fast if your clutch is slipping), thus allowing your magneto to generate a strong enough spark to light the engine. Magnetos are dependant upon input RPM to make spark. And that would be why you would want to check your clutch adjustment.
If you have an open primary its easy to see if the clutch is slipping while you kick it...
Otherwise,if your clutch is adjusted well AND if induction proves to be sound (you're really sure it is, right?!?!). Then I think three things:
1.)Your ignition timing may have become advanced,
2.) your spark plug gap may be TOO large (should be 0.015" to 0.018", I run at 0.015" for mags) or
3.) your magneto may need a freshening. Those little Morse Fiarbanks units are just that, little, and the amount of spark they develop during kicking, even when freshly rebuilt, is pretty weak compared to a battery ignition set-up.
A quick and dirty way to check for clutch slippage: Remove clutch inspection cover. Make a chalk mark on the outer clutch plate. Make another mark on the outer basket. The two marks must point at each other.
Now kick it over a few times. If the marks are no longer aligned, then your clutch is slipping.
If it's slipping, remove the clutch linkage rod. This will get rid of any tension. Repeat the test. If the clutch is still slipping, make sure your clutch lever rod (that goes over to the right side of the trans) is not hard against the oil tank thereby still putting pressure on the clutch plates. If it is, adjust it so that the it isn't pushing on the plates. If you STILL have clutch slippage, you can try tightening the springs. If that doesn't work, you'll need to overhaul the clutch to see what's going on.
If the clutch isn't a problem, do the pressure test. Sounds like the only thing you changed was the pushrods, so that should be the first place you look.
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you are great...... Thanks a lot for your advice!!!!!! I ll try to check and I ll let you know about my clutch!!!! Thanks again