it has been a couple of years that it is happening, after leaving the bike in storage for 4-6 months , it will start on one cylinder, then after few seconds it will run properly.

the first time I though an injector was sticking but I am not really sure... any similar esperiences?

Thanks

If I had to guess I'd say after months of sitting air in the fuel line
Would be the likely cause or maybe a sticky or shot
Check valve in the pump
Quickest way to figure out fuel issues as Im sure you know is a pressure gauge
And this assumes the more mundane and common issues are not in play....clogged filter, intank fuel lines , funky spark, ground problems,ignition switch...you've been there

Dont ya just love it when folks post question then dont follow up

Hi Higgy,

I understand you: i assume he's still cranking

Frank

(I've had similar experience once due to stale - modern s**t - fuel)

Anglelix has been around for for a long time,kinda surprised actually

sorry guys , I have been working hard finishing a long term project and I am revamping my lab so I lost track of the time.

my 907 is in Italy, I am in the UK, so I will be in position to check it only when I am back there.

when it runs , it does it flawlessly, but it has been already a couple of years that the first start after a long stop (3-5months) is proving somehow "difficult"

Usually it cranks 1 turn and a half and the engine fires, but lately I had a couple of episodes when it starts after 4-5 turns and then rund on 1cylinder for few seconds.

When it happended the first time I got some injector cleaner, this time I just filled the tank with fresh petrol and went for a ride (and what a ride it was 10 months I was not touching the little Elefantino)

unfortunately the issue is not repeiting itself every time so cannot pin point which cylinder is not firing.

I need to find sometime to do some work on it I am doing 500miles a year so there is little wear ,neverthless the years pass by and few things need addressing like the intank hoses and fuel filter, last time I did those was 15 years ago.

by the way, do you know the hose diameter? 1/4" or 5/16"

First thing I`d try is a fresh set of plugs, KISS...