Ducati Monster Forum

OK. After seeing the predicament of our young comrade in the UK with his stripped carbie float bowl thread, I'm reminded of the carbie freezing saga of 1996.

I purchased a new 1995 black (metallic charcoal) 900 Monster in early 1996. After air box and jetting mods with open pipes she made a whopping 77hp and 63ft/lbs of torque [laugh]! After riding Harleys and old Triumphs for years I was excited! [cheeky]
By winter here the thing wouldn't run as soon as the temperature hit 15 deg Cel! I got a carbie heating kit fitted under warranty from the dealer who was genuinely supportive and right behind the customer. The kit didn't make a difference. I thought that maybe my open air box mod wasn't helping, but other owners of stock bikes had the same problem. Hey, the air box/jet kit was in the DP catalogue.

I went back to the dealer who spoke to the importer on my behalf, but there were no other solutions. I starting dealing with the importer directly and was put onto the importer's technical adviser/liaison guy for Ducati and Harley. Here's the thing, Harley were running CV carbs on their bikes at the time and having owned a '93 FXR those carbies iced up also.
The guy had no solution except to add an antifreezing additive to the fuel. He recommended the kind of additives used by people running vehicles in alpine regions. I couldn't find it anywhere in Melbourne. I thought this was unacceptable as I knew it was the particular design of carburetor that struggled in cold wheather. (Some Kawasaki ZXR's had this problem also). I solved the problem on my Harley by fitting a flat slide carb (Mikuni 40mm smoothbore). The group I used to ride with numbered 15 Harley riders, and about half had later model bikes (at the time) that would all pop and fart on those cold night runs. The guys with flat slide or S&S, Bendix and Keihin butterfly carbs didn't have a problem. Only the CV carbs struggled.

So dealing with this technical guy for Harley/Ducati again... I asked him if Ducati would give me a deal on the FCR kit in the DP catalogue. I was prepared to pay to fix the problem with their carb and only wanted a good price. Not even interested because that would set a precedent! Imagine all the people lining up for their cheap flatslides.... [evil] He said that the Norhern hemisphere didn't have this problem because the fuel companies put the antifreezing additive in the fuel during production. Hey you guys up North, is this true?

Now I find on my current Monster that the CV carbs don't ice up very much at all. Very rarely and only rough running (stumbling/missing) just off idle. This current bike has higher compression and ported heads and manifolds. The stock manifolds are very rough from the factory and mine are cleaned up. A factor?

So what solutions have people tried. What worked and what didn't, besides a change of carburetor?

I was wondering if the newer, denser premium fuels reduce icing. I use them with the higher compression pistons.

What about a manifold "sock" with heat insulation in a tyre warmer type material that you can Velcro onto the manifolds in winter? You let the bike warm up and the heat stays in the manifold to stop the icing [laugh].

Does anyone buy an anti freezing additive?

What about electric float bowl warmers? This has been applied in cars hasn't it? Sounds scary to me, electricity near petrol/Gasoline. You wouldn't do that with an old Triumph!

Cheers
Tony.

never had a problem in Tennessee (now in Texas which is usually not as chilly in the winter) with carb icing on my M900. Heard about this kind of problem in cars before though.

I've also heard the carb heater was crap.

When lower than +12C, the oil bowl heater + anti freezing additive worked quite well
over here in Sweden w similar springs and autumns like UK.
But happier w FCR`s... [thumbsup]

Often, the icing comes from moisture in the air, not the fuel.  This is why icing usually happens at above freezing temperatures accompanied by high humidity.

So riding over a misty mountain on a cold night might be worse than a really cold night with low humidity?

I note that some people can buy anti freeze additive too.

Any European and American riders want to comment on different fuels available and how they perform in the cold?

Thanks guys [beer]

Absolutely...that's when my bike acts up. Usually around 40 degrees.

I don't think fuel additives help.

I noticed carburetor icing on my 1997 M900 Monster only when the temperature was between 30 and 40 degrees F (0-8 C?) and the humidity was fairly high.  The only symptom was that it didn't want to idle after riding for ten or more minutes at speeds above 35 mph.  Typically I would ride a good twisty road for about ten miles, then get to a stop sign and the bike would die if I didn't work the throttle to keep it running.  I usually had to have that happen once or twice before I was able to do the right thing to keep it running at a stop.

The issue went away if I stopped for five minutes.  Engine off or on didn't matter for melting the ice.  My personal solution was to quit riding when it gets that cold.

My fuel injected Ducatis don't have the the problem and I haven't noticed it on my Honda XR650L either.

Carb icing is more likely when the dew point is close to the air temp. Usually above freezing but chilly. As air rushes into the carbs the pressure drops as the air is accelerated thru the carbs. this pressure drop removes heat from the air causing the moisture to freeze. Result carb icing.  ;D

For an example it is kinda how your A/C works.  Pressure drop removes latent heat from air. Result cold air.