Ducati Multistrada 1000DS Over Fuelling / Starting Problems

Published on 20 February 2023 at 17:51

The non start problems with the 2003 Multistrada continue - I have ruled out the starter, battery and wiring, this is a weird one. I did lots of experimenting and found that if I started it on the vertical cylinder only it would start or at least turn over ok, it's when I tried introducing the horizontal cylinder that things turned a bit naughty - so naughty in fact that I have renamed the bike the Naughtystrada. Anyway, that's not important right now, what is important is that when I pulled the spark plugs the two for the horizontal cylinder were thick with black soot, the rear cylinder ones were clean and the correct colour. This is absolute proof that the two cylinders were running very differently, with the horizontal one over fuelling dramatically.

This theory was proved in spectacular fashion when I decided to check the spark - it was a nice big , fat blue spark that did an extremely efficient job of igniting the cloud of fuel / air mixture that was ejected from the horizontal cylinder.

It was quite a joyous thing as it at least told my that I was definitely getting a serious over fuelling of the front pot. My in built sub optimal scenario sensor had sensed something seriously sub optimal - further investigation was needed.

This is where the real heartache started - anybody that has had to strip one of these bikes to get at the inlet system will recognise my pain. it took forever to get at all the little hidden nuts and bolts, all the fairings had to come off except the front upper one, it took forever, I lost a fair bit of blood and I shocked even myself with the language I came out with. 



ducati multidstrada 1000ds seat removal

Once all that is free you have to remove two quick connectors that are on the fuel tank - that is far easier said than done but with those and the fuel pump / sender connector removed I could slide the entire tank and seat assembly back, up and off the bike. Quick note here - mark the connectors, they are both the same but one is flow, the other return, looking at the set up I don't think it matters which is which but just to make sure I used a dab of Tippex so they go back on the same way they came off.


Ducati Multistrada 1000ds with seat and tank removed

It looks very different naked, it's pretty filthy and really needs a good clean, it will get that before it all goes back together. it is pretty obvious that somebody has been in there before, there were numerous nuts and bolts missing and those that were there were often finger tight - the clamps on the air hoses where just hanging loose. I wouldn't be at all surprised if somebody has already looked in to this problem. Anyway next job was to get the air box off so I could at last see the injectors, they both looked a but rusty on the body, the front one much more then the vertical one.


Ducati Multistrada 1000ds Fuel Injector top view

In the image above I am pointing at the fuel connector that feeds the horizontal injector, it is held in place with a t20 torx bolt that has to be removed before the injector can be pulled out of it's socket. The electrical connector also has to be removed - it's retained by a spring clip - another challenge to test your patience.


Ducati Multistrada 1000ds inlet tract

Not sure how clear it is but hopefully you can see from the photo above that the inlet tract is wet - it really shouldn't be in an injected engine. I reckon that's further proof of the problem. I removed both injectors - I don't see the point in only replacing one, both look a bit worse for wear. I have a pair on order, they should be here in 2 or 3 days with a bit of luck.


Ducati Multistrada 1000ds Fuel injectors removed from bike.

Just for a laugh i thought I would try blowing through the faulty injector and sure enough I was able to do so - at the pressure the fuel rail has it must have been really chucking fuel in there.

I still don't know for sure if this will fix my problems but I am 100 per cent sure it will make things better. If it doesn't I really can't justify spending any more time on it and I will have no option but to sell it on or break it - it's not commercially sensible for me to go any further with it. It would be a shame but I do this stuff to earn a living and it's already had far too much time for the price I will get for it.

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