it's definitly not the decomp solenoid that's amking the starter keep turning over.

Here's an extremely simplified wiring diagram that my help.



you may have a faulty starter switch.  A lot of older bikes have had these go bad, usually resulting in nonstarting.

bad starter relay or decomp control is likely, IMO, or a short somewhere there.

so you've shorted +12V to the Y/G going into the decomp control?  that should make it keep trying to start all the time, assuming the start switch is out of the loop.  if it's on the other side of the clutch lever, every time you pull the clutch lever, it should try and start, then.  I can imagine that if the start swithc is in the loop, and you have a lousy switch (and return spring), a bump could occassionaly try to start the bike in the scenario you have described.

I have an intermittent start problem myself. Start button works, or, not. I've taken it apart, cleaned contacts & bypassed sidestand & clutch interlocks. I KNOW it's the start circuit. I put an emergency start button under the frame rail under the right front of the seat. There is a red wire under the seat & I ran it to a switch & then to the decomp controller. The decomp controller fires the starter after a short time. I used a switch out of the front of a dead dvd player, a microswitch of minute current carrying capacity & it has worked flawlessly. I do have it stuck in 2 fingers off of a blue nitrile glove, still on the circuit board & tie wrapped to the frame. This wont solve a starter problem, but will sure let ya know which end O th bike has the problem. Gregs answer looks more like the answer than mine, I just tossed that in just in case.

There are 2 possible reasons for Your problem:
1. the starter is getting power all the time when the engine is running. You can check if this is true if You start the engine and disconnect the starter "hot" wire. If the starter stops spinning, chase the problem in the starting circuit.
If this doesn't solve the problem, go to :
2. Starter clutch.

I noticed in my push start technique that when the clutch is let out the starter shuts off.  Makes sense that it should.