Help - Fuel Pump Wont Stop Priming, Bike Won't Start

Hello Dave, the fuel pump is supposed to run constantly so no problem there, check that the choke is operating when you apply it, i.e the mechanism moves (I'm assuming you have a carburettor model, I don't know anything about injection models), I doubt it's developed a fault in just a few days since it was last started, check your battery is supplying over 12 volts as well, cheers Mark.

 

OK, check the battery under load as well, it's common for a poor battery to show a good voltage straight after charging and unloaded but it can take a dive as soon as the starters pressed, also leave the throttle alone when choke is on, if it doesn't start knock the choke off and pump the throttle whilst pressing the starter, good luck.

 

If the pump is going on ok, great, check the spark plugs for wetness, if they are dry, then you arent getting fuel, check for spark too. It'll be one of these two. Narrow it down to which one, then you will know if its electrical or fuelling.

 

The oem starting circuit cables, the ones between battery and earth and battery and starter and starter solenoid develop resistance over time. Combine this with s less than prime battery and although you may have enough power in the battery to turn the engine over, there isn't enough left over for the ignition circuit as well.
This is a common problem with Ducatis and the solution is to buy a starting circuit kit from @Exige on here and also an AGM type battery, preferably a Yuasa. AGM batteries pack a much bigger punch for starting than ordinary lead acid batteries, so are ideal for Ducatis.
Combine one of Exiges kits with an AGM battery and your Monster will start beautifully.
Doing this is the best money I've ever spent on my 999

Ps The fact you get a backfire says you are getting fuel and a spark - of sorts...

 

12.3 Volts is not a good enough charge in the battery - it is only about 60% charged. It needs to be at least 12.5 Volts.

 

It does amaze me that 0.2 of a volt is equivalent to a significant proportion of the charge...

 

When my reg/rec packed up I was riding the bike luckily back home and as it started misfiring, popping and banging, I switched the lights off which gave it a bit more life for another mile or two getting me to within a mile of home when I parked up as I thought I was doing it no good at all, when I checked the battery 10 minutes later it had 10v left in it and that wouldn't keep a bike running never mind start it.
Steve

 

If you really want a top notch battery I cannot recommend ODESSEY high enough. It cranks forever, and by far the best battery I have had on any of my bikes. You cannot leave them on a tender though (unless its theirs), you have to charge then remove, but they hold charge very well.

 

Hope it's a permanent fix but it may not be. They may just foul again.
I ended up installing uprated coils on my SS to cure plug fouling.
Still a good idea to get the cable kit and a better battery, if and when you need it.
It will instantly transform the bike from a reluctant starter to an eager starter.

 

New on here, but I've owned my '94 750SS from new. Over the years I have found my Ducati doesn't like starting when it's been left unused for long periods. Very different from my Japanese bike.
Anyway, when I use it now once I get close to home I always turn the fuel off at the tap under the tank & run the carbs dry before parking it up. This seems to help a great deal when starting it the next time I use it. Having said that I do still have to resort to changing the plugs sometimes before it will run correctly.
Basically if it doesn't start & run on both cylinders straight away I just change both the plugs for dry ones. Normally it is the front cylinder that plays up though.

 

Never had to pull a plug again, once I'd swapped to the unrated coils...

 

When I first got my '97 750ss in 2009 it used to do exactly the same thing as described here and the 'cure' was almost the same - I didn't turn off the petcock, though.

What I did find is that it was worse in winter (ie cold and damp conditions) but if I got the bike into the sun for about 15 minutes it would start. After having had carb troubles and servicing them, changing plugs (always used NGK) and leads etc, it didn't play up. I sold the bike in 2016 and I don't know how the new owner is getting on with it.