1922? Model TT last plated (run?) 1996
What I have done,
changed oil, anti freeze, drained differential refilled 600 weight
greased worm gear and all fittings
Replaced carb Langs rebuilt NH
no in line fuel filter yet
replaced coils with Ron Patterson rebuilt
replaced and gapped plugs
replaced spark plug wires
one tire needs jacked up to start ( high speed spin in neutral) I will loosen low speed band
Will NOT start on magneto BUT once started runs MUCH MUCH smoother on Mag than battery Will NOT run smooth on battery
On battery starts runs rough adjusted carb mixture to get a smooth a running as possible BUT
when enriching fuel mixture from full in stop (lean) to one and a half turns out engine backfires and exhaust turns cherry red (this should be opposite? As you LEAN out fuel it should be hotter)
I will check the compression and where number one spark is sparking in relation to top dead center this week
I SUSPECT leaking intake manifold (yuck I hate changing those) trying to get the old exhaust nut off
Any other ideas to check ??
If it runs well on mag but not battery you are using the same timer, coils, carburetor etc, therefore those are probably not your root cause. Check the circuit from battery to the coils. This includes the coil box and connections within, wiring, key switch and amp meter. I'm going to point at the key switch as my first guess. Set your carb needle where it runs on mag and start your battery trouble shooting. Also making the assumption that your battery is good and charged
Air up the tires or you'll be riding on rims.
Check your battery cables making sure all the connections are clean and the cables are in good condition. Old cables could cause a problem. Also check for nicks in the cable.
David Heavner ? Thanks never considered this as a cause. I took the negative ground strap off and burnished metal to frame contact bright before starting. Anything else there to check? Starter works fine
Brian Healey you may be on the something with the key switch as the light switch also does not work. Should I just change out the entire key switch or check the tiny screws and burnish metal connections n the back of the switch?
They always run better on mag than on battery if your mag is in good condition. How does it run on battery after it is warmed up? Try adjusting the carburetor while it is running on mag and get it as smooth as possible then switch to battery. Does it misfire or just slow down when you go to battery?
The magneto will usually cause the engine to speed up compared to battery.
Do you have a starter? If you do have a starter and it works, the problem would not be in the cable from the battery to the starter switch, however it could be a loose connection somewhere else in the circuit between the battery and the ignition switch. The contacts and connections in the coil box should be OK.
Another thought depending on what kind of timer you have. When you run on battery, the spark comes when the rotor meets the contact. If those contacts are unevenly placed such as a worn or burnt timer or if the timer is not centered with the camshaft, you could have a difference in timing from one cylinder to another. However, when you run on magneto, the spark comes when the magneto pulse reaches maximum which might be in a different spot than where it runs on battery. So in that case, you would run more smoothly on magneto.
You didn't mention timing. It may not be your problem, but it doesn't hurt to check. http://dauntlessgeezer.com/DG97.html.
Change "no in line fuel filter yet" to "no in line fuel filter ever".