| Author | Message | ||
     Gowindward |
I road to work this morning it was about 10 degrees and 90% humidity. I had ice build up in the throttle body and kept the throttle from opening up completely. I could only get about 3000 rpm out of the motor. After getting to work I let motor warm up a little before shutting it off. Came back out 5 to 10 minutes later and the throttle was free. I figured the heat from the engine transferred into the throttle body and thawed out the ice. I guess I need to let the bike heat up a little more so the intake track picks up some heat before I take off. | ||
| Tramp |
If your intake is still that cold, your engine isn't really warmed up enough to GET 3k rpm. it did you and your cold, lump oil a a favour. Don't take off until you feel good heat at the carnkcase, in 10o F that should take about 6-7 minutes, no less. You want to warm up your throttle body? get your engine to op. temp. before you take off. | ||
| Tramp |
remember- let it heat up for your engine, so that oil gets way up to the topend, etc. | ||
| M1combat |
Yeah... let it warm up for a full two minutes always. Even in the summer. (I go three in the winter) | ||
| Blake |
A carburetor besides being a carburetor, is also a very effective evaporative cooling system. The evaporating fuel is doing the same thing that freon does in an air-conditioner, going from liquid to vapor and sucking up a lot of heat energy to do so. Old piston driven aircraft have heaters on their intake manifolds for a good reason. Not sure what the solution to the freezing throttle problem is, other than to avoid riding in such cold and humid conditions. I guess you could wrap some heater tape around the intake manifold and rig it to the electrical system. If you are running a good synthetic, I wouldn't worry to much about the oil getting heated up. Dang, riding in 10oF! OUCH! | ||
| Gowindward |
Blake, I was thinking of "carb heat" on small aircraft too. The bike was pretty warm when I took off. (warm not hot) I ran down a mile from the house and shut it off to get fuel. The was probably the start of icing when it was shut off. The 90% humidity with 10 degree temps I don't think is normal. I would guess with that kind of temp that the air would typically be much dryer. Yes, if I run into such high humidity and low temps again an extended warm time may help, but like Blake said, the throttle body is a very effective cooling system, and it may not matter how warm the engine is to begin with the amount of air being sucked through the throttle body at 3000rpm will chill it out no matter what and with such high humidity it will ice up. The best thing is that it didn't freeze open! Dang, riding in 10oF! OUCH! Blake can you say "GERBING!" | ||
| Tramp |
I ride too much in the winter, my own warmup isn't just for the oil and the carb. The base gaskets should really expand before puttin' the spurs to 'er, and that requires heat. same with rockerbox gaskets and others. cold buell pistons are slightly barrel-shaped as oposed to perfectly cylindrical, and as the warm up, they straighten out. head gaskets like some warmth and expansion, as well. in anything below 20oF my scoot really likes a good 4 minute warmup. below 10oF or so I'll give her a full 5 minutes static then very little throttle for a couple more minutes on the road. | ||
| Davegess |
On my other twin, the 2CV the exhaust crossover pipe is part of the carb mountiung plate. The pipe runs directly below the car and in fact passes through the same mouting block that the intake manifold uses. Seems to heat up the carb very fast in cold weather. I don't think bike designer give a lot of thought to cold weather running as most of us use the cage when it gets that cold. | ||
| Mikexlr650 |
2cv ? | ||
| 1313 |
The 2CV in question, as taken at this years Homecoming:  Made by Citroen (French) and a VERY popular form of transport in Europe. 1313 | ||
| Tramp |
let your carb heat at the same rate as the engine | ||
| Johnnylunchbox |
Ahh Le Duex Cheveaux. What a classic people mover. At one time about as ubiquitous in Europe as the FIAT CinqueCento (500cc parallel twin) Wish I had a pic of the 500. I remember the Citroens having some seriously fancy suspensions for their day. Height adjustable air ride suspensions and such. They were kind of like the French Subarus. They were really cool, even if they were French (I can say that as I have a bit of their ancestry) | ||
| Johnnylunchbox |
Oh to get back on topic. A bit of gas line antifreeze (aka isopropyl) probably wouldn't hurt unless contraindicated by present Buell gurus. | ||
| Dragon_slayer |
Gowindward, you are talking relative humidity not actual moisture content. Any temperature of air can be at 100% relative humidity (RH), example dew and frost in the morning. Condition, air at a relative humidity below 100% RH during the day is cooled at night to a temperature low enough to be above 100% RH. Air can not hold more than 100% RH so dew or if cold enough frost. Guess what is happening in your intake, frost building up in layers = ice. The measurement of relative humidity is the amount of moisture in the air at a certain temp verses the total amount of moisture that air temp can hold. So the term relative. I hope this makes it a little clearer for you. By the way, the term relative humidity is not understood by most people. And yes, you are correct, warm up time will not help this condition for the reason you stated. | ||
| Oldog |
all of the carb heat systems I am familialr with had a valve (flap) in the intake line when on the air was drawn in through a anular pipe section around the exhaust. Carb heat is required in aircraft (piston) even to temps as high as 70f! because of ice formation in the intake tract, under partial throttle conditions, Carb heat also effectively reduces power output from the engine because the air is less dense, your engine quits at 500 feet and you are low or slow, you could have a very bad day .... | ||
| Mikexlr650 |
familiar with farmers car, thought tramp was discussing a bike | ||
| Tramp |
so did tramp. and it's dead wrong to say that warmup time won't help this condition. the carb/TB are situated very close to the heads. thye'll get up to operating temp as quickly as will the heads. of course, I know this only from exhaustive experience with regard to knocking the snow off my S2 and strating it in minus 0oF weather daily through many a winter, so don't consider my advice. let's talk about cars instead. | ||
| Road_thing |
I hope I never get any experience in operating cars or bikes in sub-freezing temps! Ah, balmy South Texas, ya gotta love it... rt | ||
| Bomber |
there are some conditions that'll cause ide buildup even with a lenthy warmup, but they're sorta kinda few and far between -- some scoot manufacturers have added heating to the carbs to stave off just that issue I suspect you're right about the gas stop starting the ice build-up -- when it gets chilly-willy out, I just let the old dear mumble to itself while fueling up -- if it's that cold, the station attendant ain't gonna come out anywho ;-} | ||
| Glitch |
I don't ride when it's below 30o unless I have to. But when I have, I just make sure the bike is nice a warm before I take off. The only thing I've had freeze up on me was my choke cable on my Bandit. Wish I had a pic of the 500.  | ||
| Tramp |
lengthy warmup (8 minutes in -10F) warms my carb so it's warm to the touch on the outside. There simply will not be ice in there, at that point. don't take my word for it, though- give it a try. (which reminds me- I need a new choke cable...DAVE!) | ||
| Johnnylunchbox |
Glitch - cool nice pic. I remember riding around in one of those as a kid. |
