2001 aprilia sr125 trouble starting/flooding

Fixed an electrical fault and got the bike started after years in the garage, was starting on first push of button with no problems at all. I then filled up the fuel tank and the oil tank took it for MoT and when I went to collect it it would not start.

Finally managed to start it by cranking it and opening the throttle fully, fired up slowly after maybe 10-20cranks after a few minutes of idling and bogging/cutting out it ran fine. Could turn it off and back on with no problems at all. The problem seems to be if it’s left for any length of time. Now I’m pretty sure the carb is flooding as there was fuel in the intake, I’ve stripped the carb down and refitted it and there was some dirt in the float. However on refitting it seems to be doing the same thing. This problem only seems to have arisen after filling up with fuel? A side questions when I take the fuel pipe off the carb should fuel drip out or should it be stopped by a vacuum?

Thanks
Rhys

 

Just to add it has absolutely drank half a tank of fuel in hardly any miles

 

How long has it sat unused for? Could you have some water/condensation in the petrol tank?

 

Has hardly been used for 10 years lol and hasn’t been used for the last 2 at all. Thing is it was running perfect until I filled up, and once it’s started it runs fine, the intake is very wet I’m sure it’s flooding. I’ve stripped the carb back down completely and am going to give it a thorough clean although it all looks good even the float needle seems ok. I thought maybe the vacuum tap was broken and this is causing the carb to flood although the float needle shouldn’t let any in regardless of whether the fuel will flow through the lines right?

Would it be possible that if the choke was stuck on this could flood it? Or would it still need to pass the float needle?

On a side note it’s a malossi 172 with a 20.5mm dellorto carb, standard airbox, gianelli freeway exhaust and it has a 78 jet in there, this seems low no?

Thanks

 

Change the fuel tap, the diaphragm is probably stuck open or split.

 

So I’ve rebuilt it all I’ve checked the float floats, I’ve also blown in through the fuel pipe and when I put the float level it blocks it off, I’ve sucked on the vacuum pipe and the fuel pisses out of the fuel line so I’m guessing it’s just dribbling out what’s in the line below the tap when I removed it before, when I stop sucking the fuel shuts off. I left the air filter off and an hour later i can see fuel around/in the intake, it started up a little easier than before but still slightly flooded. I feel like giving up now lol. My only guess is that the float needle is not sealing 100% but it seemed a good seal when I blew in through the fuel port I’m debating just putting in a manual fuel shut off valve before the carb. Opinions?

 

Fitted a shut off and the bike will start first click of the button after it’s been left as long as the fuel is shut off, I’ve got the intake open and when it’s running it’s still fuel dripping out/ wet when running, could this only be the float valve needle causing this ( have a kit on order) or something else like the choke?
Thanks
Rhys

 

Fitted new float kit with needle valve and problem is all sorted in case anyone has a similar issue