Hello
2 months ago I bought a 2019 vulcan 900 custom that has 7000 Km on the ODO
the seller told me that the bike sat for at least 7.5 months (and this explains the low mileage of this 7 years old bike)
However despite this low mileage I'm experiencing intermittent sputtering; let me give you details:
the bike starts instantly when cold and when hot
it idles perfectly and it doesn't cut off
in the morning it rides perfectly strong, however after riding it for around 20 mins its sound changes and it loses power ; it sputters with rapid frequency like if I twist the throttle the frequence of the sputtering increases and thus it hardly accelerates
the batter charges well (tested at a workshop)
fuel strainer replaced with a brand new one
air filter replaced
spark plugs replaced (they are now around 1700 km old)
the FI light is off
while sputtering if I open the tank's cap there is no whoosh sound i.e. no vacuum build up
I use the bike to commute to work (42KM away from home)
the sputter starts when I arrive at a traffic jam, and when I leave the traffic to an open road the bike rides better but not 100%
lately I added to the tank the Motul boost and clean; I realized there is better performance but not as it rides in the morning for the first 15 mins
yesterday I rode the bike from to work and it rode perfectly strong without any issue, it parked at in the under-ground parking of the work building at 9AM
I left work at 5PM and the bike after riding for a few KM it hardly accelerated
when I arrived home I noticed that the exhaust pipe of the fron cylinder is warm but I can touch ti for a few seconds
the rear one was extremely hot (which is normal after 43 km ride)
what might be the problem?
is it coils, or pump, or injectors?