Motorcycle Repair: starting my motorbike, yamaha tdm 850, water intrusion

Question
-------------------------
Followup To
Question -
Hi Chris

I have a 1997 Yamaha TDM 850.Recently it has started complaining about starting up after being out in the rain or first thing in the morning when damp from morning dew.
When I try the ignition the starter really struggles to fire up the bike and I always have to pull out the choke to assist. The engine coughs, splutters and back fires. If I leave it a couple of hours to "dry" the engine will usually fire up straight away.
I don't think the problem is the spark plugs because these were replaced not long ago.
Any suggestions?
Answer -
Hi Denis.
 You may want to look for signs of water intrusion into the electronics and electrical connections.  There could be some bad spots or connections that don't work too well when wet, or there could be some spots that are grounding when wet.  BAsically, you need to go over the entire ignition system in search of bad/dirty/corroded connections and spots where there could be arcing against the frame/engine or other wires.

Good luck.
FALCON

Thanks for the quick reply Falcon.

Does an electrical fault cause backfiring? I ask because I recently has to change my headlamp bulb and I know water can get into that area easily. Could this mess up the starting? Or does it have to be something like the starter motor?

Denis

Answer
Hi Denis.
 An electrical fault can, but will not always, cause backfiring.  Whether it does or not will depend on what circuit the fault is in.  If it is in the main wiring or in the ignition system, you could get backfiring.  If the timing is off, you could also get backfiring then.  Backfiring could also be caused by build-up of fuel in the cylinder during a failed startup.

 Now if the starter motor doesn't turn over, then you should look fo bad wiring or contacts in the switches, connections and starter motor.  They could be dirty and need cleaning.

Good luck.
FALCON