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pate
27.08.2009, 08:51 PM
anyone able to offer advice:confused:
I have a 1989 750 Paso with Webber carbs. The bike is as it came from the womb other than a pair of open Swona cans.

Trouble is when the bike has been sitting for a few days, it is not so keen to fire, when it does it chimes in one one cylinder, always the vertical, when I took the horizontal plug out it was wet, put dry plug in and she fired on 2 no bother. It can also backfire like a bloomin shotgun going off. when trying to fire. Could it be the cans that are causing it to be rich or mabye the battery, which is new needing topped up. :banghead:

239desmo
27.08.2009, 09:09 PM
Sounds like a carb problem rather than a battery etc.
Could be a sticking float in the bowl and it is flooding when it is sitting for a period of time.
Might be worth pulling the carb off and giving it a good clean with carb cleaner through the various jets, nooks and crannies as well as check float operation to ensure float needle is raising and lowering.
Backfire can be a number of things such as timing or air leak on the engine side of carb as well as gummed up carb etc, but if it runs ok when she does start that sounds more like a float problem.
Does she idle ok once she starts?

ShedBob
27.08.2009, 09:40 PM
These things have a Weber twin choke with each choke feeding a single cylinder. There's also a low pressure fuel pump in there somewhere I believe.
Basically they didn't work that well when new but can be made to do so with a bit of input.
But for now giving the Weber a good clean is a good start.

The exhausts are a crossover I think so aftermarket cans should affect both pots equally I believe.

ShedBob

Yorky
28.08.2009, 07:10 AM
anyone able to offer advice:confused:
I have a 1989 750 Paso with Webber carbs. The bike is as it came from the womb other than a pair of open Swona cans.

Trouble is when the bike has been sitting for a few days, it is not so keen to fire, when it does it chimes in one one cylinder, always the vertical, when I took the horizontal plug out it was wet, put dry plug in and she fired on 2 no bother. It can also backfire like a bloomin shotgun going off. when trying to fire. Could it be the cans that are causing it to be rich or mabye the battery, which is new needing topped up. :banghead:


Hi Mate - i had similar issues with my 906. The starting issue was alleviated by changing the plug and lead and swapping the coil for a Kwak GPZ500 unit. The shotgun sound is due to unburnt fuel building up in the exhaust header due to it not firing and then when it does eventually fire, BOOM !! I had the local drug dealers running for cover on more than 1 occasion when this happened. Some more advice here.

http://www.ducatisti.co.uk/forum/192321-post3.html