m900 monster running rich

[andy burton]

hi all , after a bit of advice ,, I'm new to ducatis & have recently bought a carbed 900 monster , the bike is fantastic I'm sold on ducatis now ... however after a good run out on it today it has an occasional flutter !!! , stutter , engine vibe ??? don't know how to describe it really it doesn't drop on 1 or owt just runs differently for a very short time then give it some beans & its away like a rocket . .my mate followed me for a while & said theres a very strong fuel smell coming from me bike .... when I pull over and rev the bike theres a very small chuff of black from the right pipe & that pipe does smell a lot richer than the left ... not taken plugs out yet thought id ask for any info here first ... many thanks ... andy

[Darren69]

Carb icing a little then clearing maybe? Depends on when you went out and how far? They are prone to carb ice but usually under certain weather conditions (like early morning when its cool and high moisture) but usually you can tell because you lose power and it starts coughing and spluttering. Some owners set the rear cylinder to run richer because of heat, so maybe that.

Do you know the guys at SPR in Rudd? They know a lot about Ducatis, they used to race 'em

[Dennis menace]

Could be a blocked breather pipe for the tank. The vacuum builds up then gives. Using the throttle just puts more petrol in the carbs/engine for a while so giving the symptoms of rich running. Check the filler cap breather as well. Also, the carb models are notorious for flooding due to incorrect float height.

[Dennis menace]

Has the bike been modified? Dyno jet, different exhausts, different carbs? Some more info would be good.

[andy burton]

its pretty stock afaik .. apart from microns , breather on tank sounds a poss .... I will have a butchers .... thx

[Flying Scot]

its pretty stock afaik .. apart from microns , breather on tank sounds a poss .... I will have a butchers .... thx

pull the plugs first to see if you can see any signs or running rich - establish the facts first rather than look for opinions

[Flip]

Also, the carb models are notorious for flooding due to incorrect float height.

Notorious for flooding?? I don't think my 900 has ever flooded in the seventeen years I've owned it.


pull the plugs first to see if you can see any signs or running rich - establish the facts first rather than look for opinions

You have a few things to try-

You need to know where it's running rich before pulling plugs though as they can give a kind of mis-reading depending on the fueling circuit.

Carby 900's do tend to run a little rich low down but a proper plug chop will give you an accurate reading of where it matters. Remember too rich is better than too lean!!

It shouldn't mess about though so you need to establish if the problem is repeatable at the same revs/gear/throttle position- are you sure it's not just labouring a little in too high a gear and low revs before picking up?

They will shudder and shake a bit particularly on standard gearing if in the wrong gear at town speeds.

But one pipe shouldn't really smell any different to the other as there is a collector to (almost) equalize the gasses.

However, if it is a petrol smell rather than a sooty rich smell it could be dropping onto one at low revs which if you're new to Ducati's you might not realise and hey presto there's your smell.