Motorcycle Questions? Ask a Mechanic.
Hi and thank you for your question.
First, it sounds like the used ECU is no good.
2nd, it sounds like you may have a charging system problem, and the ignition system is not getting enough voltage to allow it to operate properly.
I suggest charging the battery to capacity then running the bike with a volt meter across the battery terminals to see if it is charging or not.
Let me know what you get with that and we can go forward from there.
If the injectors are not working properly, the easiest test you can perform is swap 1&2 with 3&4 and see if the problem follows the injectors or stays on 1&2. If it follows the injectors, I suggest getting them cleaned professionally. Check with a local car speed shop or auto parts store to see if they do it or have someone do it for them. Down here, it is only about $35 per injector to get them cleaned. MUCH MUCH less expensive than replacing them.
Just curious, did you swap 1&2 with 3&4 or did you get injectors off another bike?
Lets check the AC output from the stator.
Check the ACV out of the stator unplugged at idle. You should have 15~18 ACV out of all three combinations of wires coming out of the stator. If you do not have those results, the stator has failed. If you do have good output from the stator, check the DCV out of the rectifier on the red wire. If you are not getting 13.5~14.5 DCV @ 5000 RPMs on the red wire, the rectifier has failed.
Let me know what you find.
Yes. The ignition is DC powered (battery) and if the battery gets low, it will not run correctly.