I've been helping Brett get his bike going. We're at the stage of trying to start it. It turns over real slow and when it gets to TDC it stops. Another press on the start button it'll go over TDC then stop at the next TDC. The starter doesn't take long to overheat and when it does, it turn over slower. We test the voltage at the battery before it's 12+, then as it cranks the volts drop to 8+. This is after maybe 2 or 3 revs. Then we have to let the starter cool down.
We watched the spark while doing this. It starts out strong and blue then just disappears I think the volt drop caused that.So we put a relay at the battery to the coil. Now the spark stay until the battery dies. We also put a 4AWG cable to the starter and an extra ground from starter mount to frame.
Yesterday I got the idea to boost the battery in series (12+12=24) instead of paralell (12+12=12). I had an old Jeep that was 6v I replaced the battery with a 12v and then the starter spun with some authority.
So we unplugged the TCI (didn't know what 24v would do to it) hook a jumpbox in series(24v) hit the start button and the engine spun good, with no plugs in. It cranked til batery run down less than 10 revs but the starter stayed cool just the wire stud got warm.
We dinked around all day boosting, recharging, ect.
We put in both deep plugs then we put one plug in and turned it over it turned good but slowed at TDC of the plugged cyl. Put the other plug in then it stops at TDC like at begining of post. This with 24v and the starter getting hot again.
Now the 64 dollar question. Could we be dealing with a bad starter?