Join Date: 08-29-2013
Location: Dublin, Ireland
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1993 CBR 900rr weak spark.
Looking for some feedback on the weak spark issue.
Bike was lying up for 7 years. Done a full service, new plugs, new battery, flushed the tank, replacing fuel lines and carb strip and clean. Lots of other work completed below.
The spark is orange instead of the nice blue colour. Tried different plugs: no change.
Bike sometimes backfires and refuses to start. Also think Iíve killed the battery with all the charging cycles.
Was getting high resistance on electrical connections, including earths. All connections cleaned and WD40íd. Now resistance 0.2 to 1 Ohmís. Even added extra earths.
Rectifier/Regulator is good. All readings match the Haynes manual. (ordered new R/R anyway).
Stator is ~0.4 Ohmís between yellow wires and nothing to ground.
Voltage on B/W wires at coils is reading what the battery voltage is.
Coil (1+4) 3 Ohmís and HT side 25.1 K Ohms with spark plug caps on.
Coil (2+3) 2.9 Ohmís and HT side 26.2 k Ohmís.
Nonetheless I took the caps off and cleaned them and WD40íd them. The caps have around 5k Ohm's.
Pulse Generator: 440 Ohmís
Plugs are CR9EH-9
Reading ~0.2 Ohms between the other coil wires to ICM.
Good ground to ICU.
Exhausted manifold on cylinder 2+3 had holes in them. Removed them and got repaired I tuned the engine over (Ign off) and watched a fine petrol mist come out of each exhaust port. So happy with the carbsÖ.somewhat. The choke was stuck when I stripped the carbs. I didnít strip the choke on the rebuild, so I think I may have missed something.