Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Supersports: SS / SuperSport / Supersport 950 > Carb problem?

[paynep]

I've just been out fiddling with the 600ss before taking it down for a dyno session next week and while attempting to set the idle to something sensible came across the following:

I've balanced the carbs with vacuum gauges but the idle is really lumpy at 1200rpm. If I set the idle higher it is smoother, but when I blip the throttle the revs stick at 3500 until I switch off. Then when I start up again, its back to a lumpy 1200 rpm.

The carbs are exactly as I used them on the 675 last season, with a dyno jet kit with a 144 main jet.

Has anyone come across this, or do I have to strip down the airbox and carbs and investigate? Alternatively I could just leave it for the dyno........

Oh for the flatslides

[Scooter916]

Paul sounds like an air leak to me.... Check all the manifolds etc.
glyn

[FiscusFish]

[phil_h]

Could be the air screws - remember the std setting is waaaay too lean, screw it out at least 3 turns more than std. (the std setting can sound as if its an air leak, its so lean)
And the o-ring on them can get damaged ... it can come off, but stay 'inside' when you take the screws out, and then get damaged and flap about a bit when you put the screws back in.

[skidlids]

As Glyn says it maybe down to a air leak or possibly a dodgy diaphragm, Having never stripped my carbs I take it that the little housings on the side contain small diaphragms that control the coasting in-richners which could be sticking and causing a problem

[butch890]

Neverhad any problems with our 620's!
Butch

[paynep]

Cheers chaps, looks like I'll be stripping it all down to check out the suggestions

I knew that I shouldn't have just chucked the carbs in a box after Brands

Butch - I'm surprised that you know what a carburettor is - or did you borrow a history book from John?

[butch890]

[quote]Originally posted by paynep
Cheers chaps, looks like I'll be stripping it all down to check out the suggestions

I knew that I shouldn't have just chucked the carbs in a box after Brands

Butch - I'm surprised that you know what a carburettor is - or did you borrow a history book from John? [/quote
Impertanant youngster!
Corse i know what one off them is,ive got 17 off them on the baby R (carbon and titainium -of course!)
Butch

[paynep]

Originally posted by phil_h
Could be the air screws - remember the std setting is waaaay too lean, screw it out at least 3 turns more than std. (the std setting can sound as if its an air leak, its so lean)

Well, I stripped everything down (again), put it all back together but wound the air screws out to 3 1/2 turns as per the 750 ss dynojet kit and things seem better, so good call Phil.
Carbs balanced again and dyno session booked.....watch out for the bhp shock!

[phil_h]

Good news paul.
btw - where do you dyno