Does your fuel tank build vaccum pressure?

Ok folks....

Just want to see if this is part of an issue I'm having, so can you guys do something for me?

After riding your bike for a while, with fuel in the tank, put your ear to the gas cap while you slowly unscrew it and see if you hear vacuum being released when you open the tank. I have been experiencing throttle behavior problems, of late and only just recently noticed vacuum building up.

I first noticed after a complete fill up when a short while after the fill up I parked the bike and upon restarting the bike would start but not stay running... I opened the gas cap and heard a big woosh of air... the bike started and ran fine after I did that. This morning on the commute in I had reduced engine braking, wonky idle, and weird throttle response. I just went out to the bike and opened the gas cap again to another big woosh of air. If it misbehaves on the ride home, I'm going to stop and open the gas cap and ride again to see if its related.

Thanks for your help.

Bruder said:

Go to your Ducati dealer first, and read out the ECU this is the heart of the Bike! The rest you are doing pure speculation! The ECU safes all the faults you have on the bike!

Gruss Steffen

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I know. However, the local dealer has the attitude of "drop it off and we'll see what we can do with it when we get to it". There's no "while you wait" service. There's no "same day service" either. So given my history of doing all my own work and services, anything I can do to troubleshoot it before I go there and hand over my bike for an extended period of time will only make the turnaround at the dealer shorter, if it needs to go there at all.

If I saw "error" on the dash at all, I'd be calling them now. I have not seen an error message, or had any flashing lights or anything else other than this weird decel problem and an incident where it didn't start and stay running unless I took the gas cap off. My guess is the evap canister is full of fuel.

Bruder said:

With the evap canister I don't have any experience sorry! With you Duc dealer that really crap!
No chance to go to free motorbike shop and ask if he can read out the ECU and leave the fault on the ECU? So at least you know whats going on when you go to your Duc dealer!

Gruss Steffen

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In New York, USA, there's very little that's free. Other than bad advice, and sometimes you even have to pay for that.

I'm going to update the other thread I started about my throttle behavior, but I'll say it here too....

problem solved....

by removing the evap canister.