Ducati Monster Forum

So my bike has 18k miles and after installing a new battery, new Denso plugs I have issues.

After riding for about 15 minutes the bike will idle low then shut off. This happens more than I wish to. So I talked to a gent at a local shop who I'm mentioned that I need to bump up the idle but he thought I had tight valve clearances. Sound right to anyone?

It could be tight valves, but I don't think so.
When was the last valve adjustment done?

12k. I checked them at 17.5 and one was tight (vertical closer I think). I don't have the room now to pull it apart so I gotta pay someone. Do you think it has something to do with the plugs? By the way, I went wit the Denso's. Are you supposed to screw on the rubber boot to the spark plug? I did.

Which Denso plugs?
S4 needs plugs *without* the thread-on end; just the threaded stud out the end.

The coil just pushes straight in.

I forgot the specific # but I thought it was on par with what guys here suggested. When I received the plugs they had a brass-like fitting atop the threads. I pulled off the fitting and inserted the spark plug. The when fitting the rubber boot I rotated it for around the threads. Don't tell me I got the wrong fooking plugs!  [bang]

Not knowing the specific number, there's no way to tell if they're right or not.
You don't need to rotate the coils when installing, just push them in, they go 'zzzzuuuk' over the threads.

I'm thinking it's not the plugs that are the problem.

Check the vent hoses coming out of the bottom of the fuel tank.
One of them may be kinked, sometimes that happens when putting the tank down.

Go out and ride the bike.
If it quits, pull over and pop open the gas cap.
See if it'll restart.
If it does, then it's very likely something is blocking the vent.

Be careful if your tank's full....

Actually I have no hoses running from the vent and charcoal canister lines. The bike starts up immediately when the bike shuts off. Maybe the fuel lines are kinked? Or Maybe I reinserted the fuel assemblies inside the tank incorrectly, causing some blockage (I just had the tank painted also). Hmm, that might be it.

I'll check tomorrow.

If you just had the tank painted, then a blocked vent is a very likely suspect.

It's best to have some lines on the vent and filler drain.
Raw fuel can dump through if some gets slopped when refilling the tank, and also the bike can pump fuel out the vent if you overfill it when the engine's hot and then shut it off and let it sit.

I'm gonna pull my tank off and take it apart and see if there is some blockage. I think it's time to have the bike properly tuned, involving a power commander and dyno tuning.

Is it possible that because of my lack of hose running from the drain and vent would "suffocate" the motor somehow and cause it to shut off?

Just thinking it's a blocked vent, how do I clean it? Plumbers snake?

Today I just added one hose to the drain and the bike run fine, then it stalled. I should mention also that I did remove the throttle bodies at one time. Will they need to be synched?

Lack of a hose wouldn't cause any 'suffocation'.

As long as you didn't turn any screws or turn the linkage rod, there's no need to re-sync.

Try blowing through the vent hose, that will tell you whether it's blocked or not.
Do it with the filler cap open.

BTW, there's two lines that come out of the bottom of the tank, one is a vent for the inside of the tank, and the other is a drain for the filler cavity.

It's also possible that the filler cap vent passages are plugged, they're quite small and intricate.

Didn't turn any screws nor the linkage rod.
I'll try to blow through the hose.
Thanks.  [thumbsup]

The linkage rod, tank vent and drain lines are clear. I think maybe a valve adjustment might be the culprit. I'll just drop off the moto for the full 18k svc. Thanks for the troubleshooting though.  [thumbsup]

Have you also checked TPS, when tps is out a bit it makes slow speed stalls common.