having now changed the tank, and fitted filler cap I rode the 750 for the first time in 8 months to MOT today, passed with no advisories, but when I turn ignition on you can hear the fuel pump priming. normally the fuel system primes then stops and you can start engine. with this one it keeps on pumping.. is this normal? noticeable on MOT when turned on but not starting to try lights and indicators
Not familier with your bike but if it was mine i would think it would likely be a split fuel hose. Steve
thanks guys, will check but hoses look ok. need to find relay then. could have gone dry after not being used.
Fuel pump runs all the time on the carb models........... Well, not all the time, but when the ignition is switched on. The carb models can't pressurise the system unless the return pipe is blocked.
There is only one other 'possible' way (other than a blocked return pipe) the system could get pressurised.... ......and that's the fuel tank breather (applies to both IEs and carb models...more likely an IE) being blocked. If the ambient temperature rose a lot, the tank could pressurise as the vapour can't get out to release the pressure, but more likely it would cause the carbs to flood as the pressure overcame the float valves........ ........however, that scenario is very unlikely and the more common issue from a blocked breather is that a vacuum builds up in the tank, causing the bike to stop every few miles or so...........or worse, the tank collapses inwards.
I found out earlier this year that my breather hose isn't blocked, filled up the tank put it on the rear paddock stand and wondered why the garage smelt of petrol in the morning, fuel was pissing out of the breather hose under the bike, moral of story is don't over fill the tank if you use a paddock stand!
Oh, so you found that out too, did you? Mind you, my workshop always stinks of petrol anyway - I have that peculiar black plastic triangular pair of boxes tucked in the frame on the left side just below the carbs which Ducati refer to as 'airbox' and 'breather tank'............the fumes come from there and the tank breather as the ambient temperature rises..........
