Icing up carb remedy?

[LJ.]

Hi... great ride out this morning but had to put up with an annoying problem with carb icing up. What are the tips and tricks in preventing this? I could feel the problem was inside and jamming the throttle slide. The only thing I could really do was to stop and allow engine to eventually melt the ice off.... and this is without any tuffnel spacer!

[bsa- bill]

Oh there's so many funny stories about how this one can be cured, but I'm a taker of Furosomide so wouldn't get to the end of telling any of them so will leave it to others

[wilko]

Reduce altitude to 10,000 feet!

[muskrat]

 Try a hotter plug to warm it all up a bit. Say go from a B7HS to a 6 or 5. May then have to use a tad richer mixture.
Cheers
 PS. remember the carbs freezing (methanol) at full crack down Eastern Creek straight. had to hit the kill button going into turn 1 at over 200KPH.

[a10gf]

Reduce altitude to 10,000 feet!

++

Maybe try applying some car doorlock (spray\oil\lubricant) antifreeze to the slide?

[andy]

it dont look nice but wrap some hesian wround it. 

[Triton Thrasher]

There's a fuel additive for this isn't there?

[Rich]

LJ
Move down this way it never gets that cold to affect the carbs in Wiltshire, if I remember correctly you had the same problem last year
Rich

[LJ.]

Thanks for the replies... some interesting comments. Yes Rich you remember perfectly and it was the cable that I think was mainly to blame however I have now changed this but still have the same problem but not quite so bad. cheers.

[manosound]

Without actually doing the design, I envision some sort of temporary baffle that would route warm air from around the barrels or cyclinder head towards the carb.

Richard L.

[bsa- bill]

I know it's possible to buy the heating elements ( wire) for heated vests and so forth, I'm thinking of a couple of twists of this around the carb body and connected via a switch to the battery should not draw to much power.
I'm sure there are brains enough here to get even more tricky with thermostats  but probably the temp could be controlled easily enough by adding or subtracting the turns around the carb body to find the optimum.

Not a problem for me, my hands would freeze long before the carb - poor circulation - (thinks umm heated gloves)

[manosound]

Actually, before suggesting the baffle, I looked up the specs for nichrome wire for this matter and one (or, "I") could caculate the length and gauge of wire needed to operate at given temperature based on battery voltage (6 or 12 vdc, of course). LJ, I thought this might be over-the-top for what you want to do, but I would be happy to pursue it if you want to give the particulars for the temperature you want to achieve and the voltage of your battery.

Richard L.

[LJ.]

Richard thanks for the suggestion! Trouble is... I have other bikes and by modifying one, I'm not going to get the benefit from it if I ride the other bikes, and its too much hassle to modify them all.

Funnily though only this morning I was seriously considering the dynamo belt drive from Manortech but decided against it as I'm not really a night time rider, although I did purchase a DVR2 electronic regulator! poor lights was more of a worry during the cold ride I had over the weekend. Seems like I've come in from the dark side where lighting is concerned. 

I've been a hard liner towards originality especially with the old Lucas mechanical regulator, I'm actually curious and excited to fit the DVR2. Watch this space!

[iansoady]

There's a fuel additive for this isn't there?

Yes, Silkolene FST. Worked for me on a Honda Dominator I had for a while.

[groily]

As Ian Anderson (aka Jethro Tull) said so eloquently in the '80s LJ - 'Walk into Light'. I'm sure you'll like your DVR, having resisted sooo loooong! I've just ordered my umpteenth DVR2 (for another bloke). I'm sure he'll be pleased, and hope you will be too 'cos I always bang on about them. Not had a prob yet, and winter's here as you say, and it's cold, and dark, and wet, and I've got lights so I don't care . . . One bike, running at 12v, even runs 'Hot Hands' over-grips (32W) AND a reasonable 35W halogen h/lamp - can't be bad as that's 75W all told (no LEDs) and it copes  . . . What joy from a dynamo bike on cold dark frosty mornings  . . .

[wilko]

I can't believe anyone rides in weather cold enough to freeze carbs anymore! Sheesh, i've done my apprenticeship!

[Rocket Racer]

what sort of carb is it? and what sort of temperatures are you running in? I've had icing problems with ducati's but they have the carbs up in the airflow. I ran a japanese inline four at temps of down to -8c without heaters or issues apart from the rider freezing his extremities off.
Cant imagine a hot english twin letting the carb freeze!
On the duke I fitted an electric carb heater, some dukes run oil heating on the float bowls.
On a BSA I would imagine a little baffling on the float bowl to reduce air flow would be enough to prevent freezing.
On the duke I would stop until the carbs thawed then set off again.
Over here the issue is currently wet rather than cold...

[LJ.]

Hi RR... I've since come to the conclusion that its probably not icing up inside the carb like I first thought. Its been pointed out to me that there is an air filter which would prevent some of the air moisture getting in and there is also a rubber boot around the top of carb.

The carburettor is just the standard 376 monobloc. It's more likely now, having given further thought... moisture in the throttle cable. I dismissed this thought at first as I have only just in the last few months replaced the cable with something much thicker because the same problems were happening last year, and, only yesterday when changing the handlebars I found evidence of some water in the throttle twist. Having said all that though, ice was forming on the outside of carb. Temperature when riding would probably have been around 3 or 4 degree.

[iansoady]

Having said all that though, ice was forming on the outside of carb. Temperature when riding would probably have been around 3 or 4 degree.

That's the sort of temperature where you do get genuine carb icing, especially when the air is very humid. The process of evaporation of the fuel lowers the temperature (remember latent heat from school physics?) Same principle as a domestic fridge. If there's lots of moisture in the air it freezes out and can partially block jets / air passages etc.

[groily]

With you Ian, it's just the humidity that does it, as temps fall towards 0°. Have had Monoblocs ice up pretty solidly quite a few times in snowy/slushy just-above-zero weather, and tis hard to get more than a few miles at a time. Sheer unadulterated misery in fact, as your hands aren't much cop at tinkering at those temperatures at the side of the road. Cold clear -10° dry-air days don't do it. But they freeze your wotsits off just the same.
But hey, it's nearly the shortest day (northern hemi) and we'll celebrate hereabouts with a few hundred classic-bike km next week in the dark/wet/wind/whatever - and then start getting excited like small kids about the return of the light. It's a disease wilko - the apprenticeship never ends and some of us never learn!