I bought at auction a SPORTSTER NIGHTSTER 2008 and was with broken engine without ECU. I changed many parts to the engine (piston, rings, cylinders, lubricators, camshafts, etc.) but could not get rods alone, so I bought on ebay a crankshaft of a 2005 Sportster and a ECU another ECU sportster 2008. (The Number ECU 32140-08)

When the engine was running the sound is good, but had Very much backfiring. When I looked at the spark plugs, the front had extremely poor and the back very rich. (definitely the engine is off point.)

I do not know if the problem is the ECU or crankshaft, I read in another post that the ECU has to be according to the VIN and maybe that's the problem?

I also thought that might be the crankshaft, but when I compared the pieces are exactly alike. In the part number gives the crankshaft Harley 2005 (23905-04) and the crankshaft of 2008 (23905-04A).
How Can I solution this problem?

I also thought that maybe the crank sensor would be replaced by 2005, because I installed a crankshaft 2005.
Sensor 2008 (32707-01C)
Sensor 2005 (32804-04A)

I need a help to solve this problem.

 

Probably better to post this in the tech side of the forum.