Ducati Monster Forum

So I've been having an issue and I don't know where to start. I went ahead and rejetted my mikuni carbs, added pods, CARB delete, and the bike starts right up and idles fine. At WOT the bike struggles, both on the freeway and streets. I can hear massive amounts of air being sucked in through the pods but the bike accelerates as if I were at 1/2 throttle. I fiddled with the carbs and took it out yesterday and everything seemed fine riding from Northridge to Palos Verdes via PCH no issues. Now today on the way to the store I tired to give it some throttle I can hear air being sucked in but it still struggles to accelerate (this was in first gear going from a stop light). After I passed the stop light the bike felt like it was going to die as in the idle was dropping even when I add a little throttle. Carb problem? Vacuum problem? Fuel problem? I really don't know.  ??? Thank you in advance for your responses/suggestions

-The bike: 97 m900
-Miles 265XX
-Jet settings: 155 main, 42.5 pilot, 4 turns out, needle 4th from top. New emulsion tubes &  needle
-Fuel filter replaced 200 miles ago.

fuel tank breather?  try riding with the cap open.

Also lift tank and check fuel lines aren't squashed, kinked or perished resulting in fuel flow restriction. Easy to do and eliminate. Lower tank carefully as it is relatively easy to catch a fuel line.

Possibly a clogged fuel filter?  If you've moved the tank around a lot, that can kick up enough sediment to block it up.  Symptoms sound about right.

Thanks for the suggestions. I'll be going over the fuel lines right now. Pending results...

Have you checked to see if the slides are opening?
Also are you sure your main jets are not too lean?

Well there was a slight kink in the fuel line straightened it out and it solved some of the problem. Still struggles slightly going from 40-80 unless i open up the throttle all the way. Fuel filter doesn't have debris in it. Probably now its a matter of tampering with the jet settings. It's difficult following the Factory Pro guidelines with no tach  :'(.

After 15 min of hard use per FP directions
(http://i479.photobucket.com/albums/rr154/justin123560/photo1.jpg)

(http://i479.photobucket.com/albums/rr154/justin123560/photo2.jpg)

Before driving yourself crazy try some fresh spark plugs.  40 to 80 in what gear?  Does down shifting help?

+1
With pods you might want to try 160 or 162.5 main jets.

Pinched or incorrectly seated diaphrams may not raise the slides.

Who knows, you may have to try needle position 3 or 5, or a 40 slow jet.

Good luck with the tuning. Be patient and test one change at a time writing each change down as you test. Dont feel bad if you go the wrong way, as what we think should happen in theory often doesnt work out when tested, at least you ruled that option out.

And +1 on fresh plugs.

+1 on the one change at a time. Turns minutes into days instantly. We've all been there once at least. Not fun.

Thanks for all the suggestions. I basically replaced all the fuel lines (yes did the manual petcock too) and noticed that my fuel pump was clogged with (white?) gunk. Cleaned it right up and it runs well. Now I can ride like a hooligan.