Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > Carb icing

[Maxypriest]

Went to Cadwell yesterday (Saturday 18th), completed 5 (2x2.5laps) whole laps…. CARB ICING. I had forgotten all about this, as my road bike 900SL has FCR’s, thus no problems (why were they not fitted as standard?). Silkolene FST is meant to help, but I have found little success with it. I hope it warms up for next weekend otherwise I’m bu&&ered!

Any ideas?

Priest.

[NBs996]

Shouldn't be such a problem next weekend, it's forcast to get a bit warmer.

But... you can fit a carb heater kit - not sure how easy that is to do but doesn't look like there's to it. Don't be telling the technical comittee you're using fuel additives tho!

[Edited on 19-3-2006 by NBs996]

[Scooter916]

Maxy
We suffered the same on thursday, it is a mare. i doubt we will have an issue next week as Nick says the weather is set to improve.
Glyn

[psychlist]

I'll just ask Domski to breathy heavily on my carbs before we go out on track, should be enough hot air to keep em filled for 8 laps :P

[twpd]

Are you allowed to shorten your inlet tracts? I had this problem on my racing MZ many years ago and I noticed it was much worse with long inlet tracts on either side of the carb.

[phoenix n max]

Should be ok next week Maxy - My lads been out today on his bike with no heaters and it was fine. Coughed and spluttered like a good un last weekend though.

[guest1]

Doesn't the carb icing occur only when in motion?

SL used to do it chronic even with pro-fst, till I used a deflector just in front of carb to take the brunt of the wind chill off of it.

[twpd]

Dunno about Ducatis but my race MZ did it when being ridden and in the paddock on the stand. I've ridden a Monster before when it suffered icing and it seemed to happen at low engine speeds. That's about the extent of my knowledge with the problem.

[Rally]

AFAIK carb icing occurs because of the petrol's latent heat of evaporation dragging down the temperature of the inlet track as it is vaporised by the jets. When the air temperature is cold to begin with, this results in any water vapour in the air forming ice on the cold metal parts ruining the fuelling of the carb. It happens when on the move, not so much because of the air flow, but rather because the carb is vaporising more fuel at that time. As soon as you stop, the heat from the engine is conducted into the carb and melts the ice.

The way I see it, there are three ways of preventing it: warm the air before it gets ingested; use a fuel additive (don't know how these work though); or fit fuel injection

I don't know how warm the air has to be to prevent icing... but I wouldn't like to bet on Cadwell being warm enough next weekend

[domski]

Originally posted by psychlist
I'll just ask Domski to breathy heavily on my carbs before we go out on track, should be enough hot air to keep em filled for 8 laps :P

6 laps :P

Cheeky blighter