Hi Guys, I have a 99 900 Monster and have basically left it in my lock up for a few months over winter. I decided to prod it today to see if it would burst into life, but was met with a stubborn resistance to start. I sprayed some 'easy start' down the inlets to see if that would work and it popped a couple of times, as if trying to start. The spark plugs are wet with fuel and showing a good spark, so I think it is flooding. Does this sound like a carb rebuild? thinking they might be a bit gummed up... Any thoughts?
Battery would be my first bet although if it's trying to start each time id have thought it'd have given up the ghost 2 or 3 times in. Have you checked that by chance?
I bought a new Odyssey battery last year, that has been great. Lots of crank power, so I don't think that is the fault. Certainly showing no signs of slow cranking like the old Yuasa.
If you have a good spark and fuel getting through you might have just flooded it, if so spin it over with the plugs out then replace them and try again. Steve
Tried spinning it up without plugs in, to clear the residue as suggested, but it appears to instantly flooding again (no choke)... it’s like it’s just dumping fuel in there, because the plugs are wet once removed.
Give the bowls on the carbs a tap sometimes the float bowls on old carbs stick if they’ve been sat a while
My Carbie M900 does this if left alone for a while, and I believe they all do it, especially if it’s been 'Tuned' with Filters, Dynojet etc. It’s fine if started at least once a week and the battery is kept topped up, but if the fuel is allowed to evaporate out of the Float Bowls the Vacuum Fuel pump can’t fill the Float Bowls quick enough before the battery runs down too much, then when the Float bowls are full the battery hasn’t got enough oomph left to start it and it floods. If you are still running the original Battery cables then they also limit Starter efficiency and sap Battery power. There are kits available to replace them with better quality, thicker ones, but I made my own as I’m lucky enough to have the right Crimp tools for the thicker cable. It’s also worth checking the main Earth to the engine is clean and tight, and if it’s been left off, as has been found, then fit one direct from the battery terminal to the engine block. If I really can’t start it, or even better use it, at least once a week I make sure the battery is fully topped up and tend to give it a few seconds on the starter without the choke and the throttle wide open before trying again with the choke on and throttle closed. This seems to get a bit more fuel through to the carbs quicker and it normally starts after a while. If it will not start before the Battery runs down I put the battery back on charge for just a couple of hours and it always starts almost immediately. I’m currently working on a priming pump system by adapting a Mikuni kit meant for Jetskis that are used infrequently, but it’s just one of several winter projects that won’t be complete for a while. The other option is to fit an electric pump that will fill the float bowls quicker, but I like the simplicity of the M900 too much to add any additional electrical equipment. Nasher
Are the symptoms the same on both cylinders? I haven't worked on a ducati carb before but if the needles arent closing that would allow fuel through, if the float is stuck or has sunk from a hole that might also be the prob. if youve got a good spark, I think you might be right about a rebuild, Its a good idea if its been sat for a while. Good luck
Some really useful tips there... I fitted a fatter negative cable to the battery, which really helps with the cranking. The new battery is better too. I think I'll try the procedure you suggested Nasher, topping up the battery charge and letting the cabs fill properly, before going full choke. If it's still not going, I'll start pulling the carbs apart. Thanks, W
Seems to be sparking okay... And when I sprayed Easy Start down the inlets it popped as if it really wanted to go. Fuel is probably 3 months old, which doesn’t seem that old.
Well after a day of tinkering (we do love a bit of tinkering) I put a new set of spark plugs in and tightened up a few wires and Bingo, she fired up! Turns out the old plugs, although sparking were weak. Nice simple one!
