View Full Version : Effing Carb Icing
<Rant>
So I had first carb icing of the year this morning.
So f***ing dangerous. Changing down and trying to blip the throttle, but oh no engine has stopped.
Great let's do an involuntary rear wheel slide with frantic cagers behind me. :shock:
Then at a roundabout: cross the stop line and engine stops! Mad pressing of starter etc. etc. :(
To tell the truth I've only had it a couple of times in four winters of owning the SV
But it p*sses the hell out of me that Suzuki would release a vehicle that has a fault like this for winter riders. Mind you the KTM Adventurer has the same problem.
I love the bike but cheap b**tards....almost makes you want fuel injection eh rounded model owners? :wink:
</rant>
so used to it happening now I ride like its gonna happen all the time :lol:
Itching 2 go
13-01-05, 03:00 PM
silkoline pro fst is the answer it cured my problem
Steve H
13-01-05, 03:12 PM
Whilst fuel injection may cure carb icing, it is still pretty s***e on bikes at the moment. Not quite the same technology as cars. Apart from icing, a well set up carb on a bike is better for fueling than current fuel injection anyday........Blame the EU and its namby pamby emission laws for that! :wink:
Cloggsy
13-01-05, 03:14 PM
Carbs :?: :? What are they :?: :lol: :lol: :lol:
Steve H
13-01-05, 03:19 PM
Cloggsy, If you are serious, you have missed out. Go listen to a couple of Weber down draughts at full chat! :D
Two tips: Raise the idle speed to 1500 (when warm) and this'll stop it cutting out completely on a closed throttle and put in either Shell Optimax or BP's new Ultimate which won't completely cure it but will make a fair amount of difference. It seems some bikes suffer badly (regardless of where the carb heaters are positioned) and some bikes don't - mine does :cry: .
As for Silkoline Pro FST, yes it works pretty well but you have to be a millionaire to use it on a regular basis.
.
Itching 2 go
13-01-05, 04:16 PM
no you dont just keep an eye on the weather forcast and drop some in the tank on those real cold days/nights
greeno76
13-01-05, 04:25 PM
Hi,
I'm interested in this too as I suspect I've been experiencing it a bit.
My idle speed drops from it's usual 1400-1500 down to 1,000 and can often cut out as you describe. It that characteristic of carb icing?
If so, I might try some of the special juice.
J
Cloggsy
13-01-05, 04:34 PM
Cloggsy, If you are serious, you have missed out. Go listen to a couple of Weber down draughts at full chat! :D
I am joking - just a bit of fun :wink:
no you dont just keep an eye on the weather forcast and drop some in the tank on those real cold days/nights
Sounds simple Joe but weather conditions change rapidly and it's not just down to cold, there's also dampness to consider too. At approx £2 a shot per tank, FST is simply hideously expensive for us financial mortals. Yes Optimax etc ain't cheap but it's still cheaper than (the admittedly superior) FST.
.
Itching 2 go
13-01-05, 04:48 PM
no you dont just keep an eye on the weather forcast and drop some in the tank on those real cold days/nights
Sounds simple Joe but weather conditions change rapidly and it's not just down to cold, there's also dampness to consider too. At approx £2 a shot per tank, FST is simply hideously expensive for us financial mortals. Yes Optimax etc ain't cheap but it's still cheaper than (the admittedly superior) FST.
.maybe but there is a cheaper alternative. stop at the road side let the carbs warm from the engine temperature and then go again its what i had to do lastnight when i got to bromly. i forgot my profst :oops:
Greeno... yes that's a good sign of carb icing...
However, changing fuel and oil as the others have mentioned; I find hard to believe that this will do anything to reduce the cause and effect of carb icing.
True carb icing has nothing to do with where the fuel goes in... it is where the air goes in!
If you really want to eliminate carb icing, get proper carb trumpet heaters - these should heat the engire trumpet, not the airflow going into them. A mechanical soluation would be to provide a warm air feed from behind the radiator into the airbox... an airscoop and hose into the snorkel kind of thing.
What a plan, now the trick is to hide the girlfrind's hair dryer so it hooks up with the intake. Gives you a little super charging as well!
Course I'll need an adaptor to get it to run off 5% of it's normal voltage and a lot more current... where did I put that electronics manual... 8)
i forgot my profst :oops:
:lol:
However, changing fuel and oil as the others have mentioned; I find hard to believe that this will do anything to reduce the cause and effect of carb icing.
True carb icing has nothing to do with where the fuel goes in... it is where the air goes in!
I fully understand your point Billy but it's a mixture of things and not as simple as it at first appears. The overall temp of the atomised air/fuel mixture has an effect on the degree of icing that occurs apparently and while it won't completely cure carb icing it certainly makes a noticeable difference that makes the situation one you can live with (just).
Oh and how is your fuel injection? :wink:
.
I don't get it :o Carb icing is no big deal. It's all part of the fun of riding through winter.
Leaving your choke on slightly will solve this issue (it has on my sv).
why not put mini heaters or a heater matrix in the air box with either a switch or a temprature controled switch.
Either when it gets too cold or you you have a problem you can flick a switch and heat the air up.
Or a pipe running from behind the radiator with an air valve, which opens directing warm air into the airbox.
What u lot think?
why not put mini heaters or a heater matrix in the air box with either a switch or a temprature controled switch.
Either when it gets too cold or you you have a problem you can flick a switch and heat the air up.
Or a pipe running from behind the radiator with an air valve, which opens directing warm air into the airbox.
What u lot think?
Sid Squid has reputedly tried every possible variation on this and he says it's not worth the effort. He's one of the few bods on this board whose opinion I trust implicitly.
.
Leaving your choke on slightly will solve this issue (it has on my sv).
Not a good idea, will strip the bores of much needed lubrication I suggest and promote advanced engine wear.
.
I will suss it out.
The main problem i hear is that the air is too cold.
Is this correct?
wyrdness
13-01-05, 09:45 PM
As I understand it, carb icing is caused by the carbs acting like a refrigerator. Evaporation causes cooling (high school physics), so the fuel evaporating from the jets cools them. Also moving air causes cooling (that's why fans work). Your carbs are sucking a lot of cold air in, so that will cool them more. The combination of these causes moisture in the air to freeze which can block the jets, causing the engine to cut out.
I haven't ridden a curvy SV with carbs, but on other bikes I've found that the best solution is to let the engine warm up before riding it on a cold day. The heat from the engine should warm the carbs enough to prevent icing from happening. However, you may have to run the engine for several minutes before it becomes warm enough. Even a bike that idles OK can ice once you start riding it - probably because more cold air is being sucked though the carb. In this case, the best thing to do, as Mr Itching says, is to stop by the road side and let the engine warm the carbs again.
No this doesn't work. You see carb icing occurs when the throttle has been held open at a constant opening (more or less) for an extended period of time allowing icing to occur within the carb and the degree of fuel/air mixture passing through is then restricted causing a marked drop in performance.
This normally happens when on a motorway/dual carraigeway for 20 mins or so when it's cold and damp.
.
Carsick
13-01-05, 11:46 PM
You could put some kind of intercooler on, if you cool the air down below 0C there won't be any moisture to freeze :lol:
wyrdness
14-01-05, 08:05 AM
No this doesn't work. You see carb icing occurs when the throttle has been held open at a constant opening (more or less) for an extended period of time allowing icing to occur within the carb and the degree of fuel/air mixture passing through is then restricted causing a marked drop in performance.
This normally happens when on a motorway/dual carraigeway for 20 mins or so when it's cold and damp.
.
I haven't experienced this. I've only had carb icing when the engine isn't up to full temperature, never on motorway riding. Having said that, I haven't done a lot of cold weather motorway riding on a carbed bike, I'd always use the (fuel injected) Ducati for that sort of thing.
I love carbs and think FI is only now becoming as good but two things irritate me about carb icing.
First, if a car manufacturer released a car that stopped when the temperature dropped it would be all over Top Gear and Watchdog etc etc. Being a minority (bikers) Suzuki get away from it. I would welcome legal action being taken against manufacturers who are negligent in this way if someone could prove it was because of carb icing.
Secondly, I find it real difficult to predict when carb icing will occur. It isn't as simple as the temperature dropping. This means that Profst and Optimax are only useful if you have predicted correctly.
By the way it makes no difference whether the engine is hot or not, especially on a twin with all that space between cylinders. Perhaps IL fours fare better as the carbs are warmed by the block?
Can any Hornet owners comment?
rictus01
14-01-05, 08:59 AM
What a plan, now the trick is to hide the girlfrind's hair dryer so it hooks up with the intake. Gives you a little super charging as well!
Course I'll need an adaptor to get it to run off 5% of it's normal voltage and a lot more current... where did I put that electronics manual... 8)
240/12v inverter, now that's something I've not tried, Hmmmmmmm?
Perhaps IL fours fare better as the carbs are warmed by the block?
Can any Hornet owners comment?
I've never had a problem on my bandit, which (like the SV) has carb heaters. However, Joe's Thundercat IL4 600cc, does suffer it, and he's got a fairing! Ah well, seems to be a bit mysterious this one!
wyrdness
14-01-05, 10:55 AM
I've never had a problem on my bandit, which (like the SV) has carb heaters. However, Joe's Thundercat IL4 600cc, does suffer it, and he's got a fairing! Ah well, seems to be a bit mysterious this one!
Some carbs are worse than others. The stock Keihin carb on my harley used to ice really badly. I replaced it with an S&S carb which doesn't suffer too badly, though iced a bit this morning.
mysteryjimbo
14-01-05, 11:09 AM
no you dont just keep an eye on the weather forcast and drop some in the tank on those real cold days/nights
Sounds simple Joe but weather conditions change rapidly and it's not just down to cold, there's also dampness to consider too. At approx £2 a shot per tank, FST is simply hideously expensive for us financial mortals. Yes Optimax etc ain't cheap but it's still cheaper than (the admittedly superior) FST.
.
Red ex or Wynns Dry Fuel do the same job. I usually get myself 2 bottles of Wynns Dry Fuel (£10) every 4 weeks during heavy winter weather. Usually lasts my 1200+ miles.
Premium fuels work well too.
Spiderman
14-01-05, 11:48 AM
I experienced this for the first time last night. Had to whizz out to see a mate and when i went out to the bike it had a lovely thick crust of frost all over it. It was only 9.30 too :roll:
I let it warm up as much as i could but it still didnt like staying on much. I just tried keeping my revs up during gear changes and slipped the clutch a lot to not spin the rear.
After a 2 hour round trip it was running like it does in summer so go only knows what the cure to this is :(
maybe he'll be nice and tell us all?
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