Hi, Maya moisture, condensation, rain, or bike washing can make the bike run sluggish, not able to rev, and misfire. Older bikes, engine configuration, and exposed electrical components are at the front of the line for acting up. During the diagnostic procedure spray Electrical Contact Cleaner on corroded wire connectors/pins/sockets etc. and apply a liberal amount of "DIELECTRIC" grease to the mating harness/wire connectors. WD40 works great for eliminating suspect areas in your quest to find the real offending gremlin.
For additional insurance you can spray a High Temp Clear Coat on the most vulnerable areas it will work like Scotch Guard does on fabric. Fabricate a rubber or plastic splash guard to deflect water coming off the front wheel getting to the front cylinder spark plugs. The design should be adequate for its purpose with the least amount of airflow restriction to cool the cylinders. The usual suspects are:
1. Air filter soaked with water.
2. Water in the fuel system gas tank and carburetors.
3. Wet ignition coil packs.
4. Spark plug boots wore out or loose allowing water to enter.
5. Spark plug cables old and cracked check for spark leakage in the dark.
6. Spark plug wells filled up and drain holes clogged.
7. Water in a wire harness that has exposed open ends and have a sharp bend or crimp allowing the liquid to form its own pool of potential threats to chaffed wiring.
8. Sensitive fuel tuners and downloaded ECM remaps may get confused with the abnormal cylinder temperature difference in a V-4 engine configuration.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
Piaggio Fly 150 4T Workshop Manual
Piaggio Fly 150 2005 2012
2008 Piaggio Fly 150
Piaggio Fly Wikipedia
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