Carb icing.

[bikenut34]

I have possibly found a way to avoid carb iceing/poor running in the winter.
For 8 years i have been fighting with this very problem and it has driven me to the point of burning my bike in a quiet field:mad:,I have tried new plugs new HT leads, PRO FST, running the bike for up to an hour before i set for work,I have moved the carb heater sensor to the front of the bike so its not next to the engine,But in one of them EUREKA moments :smt026while servicing said bike i thought i would try to displace the flow of air around the front cylinder.
I got some sheet stainless steel and cut a shield that runs along the front of the engine and blocks any air from going between the front cylinder and the bottom of the radiator the shield overlaps the RAD by half an inch and the same on the front cylinder and runs the full width of the engine and fixes to the lower fixing point of the RAD on the off side of the bike,as yet i have had not overheating problems and i have been running the bike now with the shield for 8 weeks on my 50 mile trip to work in temperaturs of a recorded -5 without the wind chill factor taken into account and the bike is running like new no coughs no sluttering no nothing i will try to put some photos of what i have done on the forum over the weekend.Give it a try if you have the same issues it worked for me.:D

[boot]

I will try to put some photos of what i have done on the forum over the weekend.

Please do, it sounds interesting.

[Binky]

Are you slowly but surely building yourself a car?

[lee67]

my tip works best....BUY A POINTY LOL:p

[Alpinestarhero]

have you tried using V-power fuel aswell?

I have been experiancing some carb icing when on the motorway, but its fine when im going up and the revs constantly on country roads

[Grinch]

Shells the best stuff for the price, as I found the BP stuff a touch lacking.

Want to see these photos though.

[sunshine]

mix a bit of 2 stroke oil in your tank, you smokes a bit but i start better these days and runs great.

[Alpinestarhero]

mix a bit of 2 stroke oil in your tank, you smokes a bit but i start better these days and runs great.

im not sure about this...i mean, im certain that it works, but im not certain its the best thing to do?

[sunshine]

theres no damage to the engine, all its really doing is adding a bit of extra oil to the little end. im not worried at all.

[yorkie_chris]

Why would it add oil to the little end unless your rings are knackered. The little ends get plenty anyway.

I reckon it'd just risk fouling plugs, and don't see why it'd stop carb icing unless it simply stops the ice from sticking to the needle.

[Alpinestarhero]

Why would it add oil to the little end unless your rings are knackered. The little ends get plenty anyway.

I reckon it'd just risk fouling plugs, and don't see why it'd stop carb icing unless it simply stops the ice from sticking to the needle.

The spark plug thing! Thats why it would be wrong. Somewhere in my mind there was something about 2-srokes and running rich...adding oil to your fuel may cause a similar problem on a four stroke.

May i ask how much oil per litre of fuel do you add sunshine?

[Essex of Essex]

Light aircraft use hot air from the engine to prevent carburetor ice or clear it if it has formed, this is selectable by the pilot and used every few minutes to prevent ice build up or when revs drop because of the ice.

It's not just a winter problem, with sufficent moisture in the air the temperature drop over the venturi in the carb can lower the temperature enough to cause the ice to form so carb heat is used year round. Light aircraft engines are mainly of old designs, four stroke boxer fours are typical just like an old VW beetle. These are low reving and prone to iceing up at low revs which is when you apply the carb heat (some work with permanent warm air like the modified SV being discussed) but this reduces power. It's a noticable reduction on a light aircraft 100hp and 2600 rpm redline are typical figures for this short of machine to give some comparisson to an SV.

[sunshine]

yes yc it stops the needle from freezing/getting icy. i dont use enough 2 stroke to worry about fouling the plugs running rich isnt really that big a problem not being able to start/run the bike is a bigger problem tbh.

[yorkie_chris]

I'm surprised oil stops the icing. Isopropanol is the active ingredient in pro-FST and gets added to 110LL in planes to stop icing in real bad conditions AFAIK.

There's no physical way it can oil the little ends though.

[Alpinestarhero]

I'm surprised oil stops the icing. Isopropanol is the active ingredient in pro-FST and gets added to 110LL in planes to stop icing in real bad conditions AFAIK.

There's no physical way it can oil the little ends though.

The only thing I can think off is the oil leaves a slight coating on the needle(s) which prevents water vapour adhering to the surface in the first place to freeze.

I was wondering how it might lubricate the little ends...are 4-stroke pistons selectivly porous to 2 stroke oil :smt037

aaahhhh na, only having a laugh. As i understand it, 2 stroke oil lubricates the bearings (little and large end and I guess whatever else needs it) in a 2-stroke engine when the petrol / oil / air mix fills the area under the piston when itys sucked in on the exhaust stroke :)

in any case, if you have found it to work, then thats great :D just be aware of extra carbon deposits occuring on valves and spark plugs

[Essex of Essex]

Ice builds up in the intake, and causes the engine to rich cut.

[yorkie_chris]

There's a video of a V-max carb icing up on youtube, the amount of ice is very small and forms around the jet needle, meaning it'll go lean part throttle and misfire.

http://www.youtube.com/watch?v=wZG_sdWuydU

Not enough forms to actually block the intake but it is enough to make it run like a dog.

[sunshine]

someone i know pointed out his 2 stroke never stuffers from carb icing so he does it to his 4 stroke through the winter and they always start first time, but he also told me only to use a small amount not to cause any damage (if any is possible) and when i stop using it in the spring to service the carbs, valves and plugs etc. since i used it this month its started the moment i try so im happy enough with it. i also use to be sat a lights and the revs would be at 3k and slowly coming down to tick over (sometimes never got as low as tick over) where as now that never happens either, we will see if its screwed the valves and carbs once its done being cold here.

[Grinch]

How much is a small amount per tank full?