Carb Frezzing Questions

[Adam E]

I sure my m600 has carb frezzing its been a nightmere to run, been down on power and sounds like only running on 1 cylinder at times.

It wont start up at all now just get the big backfire now and again but no more life its only started playing up in the cold. Could it all be linked up to carb frezzing or could it be something else? :scratch:

Cheers

[Scotty]

get some of that pro fst stuff
(or the alternative is acetone ?)

[Adam E]

Ah, i have acetone at home, do you mean add a bit to fuel or clean carbs with it (sorry for being dum)

[Scotty]

add some to the fuel
1% or 2%

i keep useing about 150 ml of the pro fst stuff

[Adam E]

Cheers Scotty, i'll try it now. If put too much in will the be any risk of engine damage?

[Scotty]

it al be reet

im tempted to run some headspace analysis at work to find out whats in profst
but not sure i can be arsed

at a low % addition its not going to make much of a difference to the vaporisation characteristics of the fuel or its octane rateing


uh the other fabled idea is to run the higher octane fuel from the petrol station, but i think it works out cheaper to run the pro fst and 'scum fuel'

[Zimbo]

If the bike is difficult to start I'd look beyond carb icing - carb icing generally only occurs after a period of running, at least 10 - 15 min, and I'd say it's not cold and damp enough for carb icing to occur at present.
When were the plugs last changed? Try a new set.
When was it last serviced, by which I mean when were the valve clearances last checked? It could well be that they need reshimming and you're losing compression due to a valve not closing properly, which will quickly lead to further damage if not attended to.

[Scotty]

fog on the tyne? why eye man , its cold enough up here was -0.5 this morning apparently

[Diego]

Had the same prob this week. Especially Monday. Added the silkolene pro fst to the fuel and presto.....problem solved. I'd best stock up on the stuff.

[Nickj]

Got to agree with Zimbo, I've run bikes in as low as -15C (still air temp) and not had any problems. Well the bike was fine I wasn't despite my best impersonation of the michelin man.

Key points are Sparks, Air and Fuel

Spark ~ New plugs Check clean and remake HT connections
Air ~ Filter good? Valves good?
Fuel ~ Filter OK? Crap in carbs? Carb set up?
More or less a service really.

[dustybin]

Got to agree with Zimbo, I've run bikes in as low as -15C (still air temp) and not had any problems. Well the bike was fine I wasn't despite my best impersonation of the michelin man.

Key points are Sparks, Air and Fuel

Spark ~ New plugs Check clean and remake HT connections
Air ~ Filter good? Valves good?
Fuel ~ Filter OK? Crap in carbs? Carb set up?
More or less a service really.

Nick - Carb icing doesn't seem to happen when it's freezing, at least not to me. It's more likely to happen at around 2 - 5 degrees when the air is cold but still a bit damp. Once it get's to 0 degrees or below, no problem. Or maybe the sound of my teeth chattering drowns out the backfire!

[banditloon]

Carb icing is gods way to tell us to smoke more cigarettes :D

Pro FST :thumbsup:

Mines started the fun of carb icing on Monday (also!!). Local bike shop has run out of FST at the moment (which is very helpful!), so I now time the run to work with doing a couple of miles before the bike goes "TOO COLD!!", go in the cafe and have breakfast, then start the bike up and all is well for the rest of the trip to work.

Check the battery connections, air filter, plugs for blockage/damage. Could just be your battery just needs a good charge (or a new one), but start with the cheapest (plugs).

[Nickj]

Carb icing can be one of two things....

The fuel itself freezes, Your either doing a few hundred mph in still air at 0C for this to happen OR it's below -30C and your going very fast.. Seriously you can discount this!!

The crap in the fuel freezes, this is mostly water content. However you still need to have an initial very cold still air temperature or be moving to give some wind chill factor to make it that cold. If it does happen I'd suggest using a different garage where the fuel isn't so contaminated, and flush out tank fuel lines and carbs.

For a fun experiment take a small container of petrol, put it in your freezer leave it for as long as you would to make icecubes.. Now does it come out looking like a block of ice? Is it like jelly? Nope its just cold and liquid.
Repeat with a little bit of added water, water component freezes, the fuel doesn't.
While it's nice and cold see if it's more difficult to ignite, ummm nope not that you'll notice and an aerosol of it will still flash up as easily as if its hot.
What you will get is the water in the carb and fuel freezing and blocking carb jets, airways etc.

[1001001001]

Carburettor icing ... In theory you can get carb icing on a +30degree day, it’s a combined atmospheric condition thing, and the outside temp does not need to be the main factor.

The problem arises in the neck of the carb. Fuel and air mix in the throat, the pressure in the carb throat is very low (low pressure decreases temp) so, if you have enough moisture getting in to your carb (from a number of sources) then with the chilly morning air, which is also quite moist, plus the low pressure in the carb, now mix all three factors (moisture + cool air + reduced pressure) in your carb throat, the moisture freezes and you get a build up of ice, and more ice forms as moist air keeps rushing through your carb, this causes the rough running and low power ...... that’s the theory.

To prevent this from happening you have to reduce or increase one of the factors, well on a bike the easiest is too reduce the moisture, you cant really put heat into your carb directly, you could try riding with the choke on .. it (may) work, just till your bikes engine has warmed the carb/s, or warm up the bike for a lot longer before taking to the road, this may help too … or …. get a fuel injected bike. I’m not a fan of additives, but I have the later, a fuel injected bike.

I just re-read this, and I didnt help at all ... just thought i would share the theory ..... :toilet:

ok, i'm going now .. :twak:

[Pingu]

I find the dear super unleaded helps

[gary tompkins]

Having run a carbed 600 for several winters, I found carb icing has sod all to do with ambient temp being below zero - more to do with humidity. Mine ran ok on some very cold but dry days, only to play up on a 3 or 4 degree day in the rain.

Tried several fixes - the only one that worked was Silkolene Pro FST

[scrumpster]

I'd forgotten all about carb icing but used pro fst on my old wheels. Fuel injection I have to say is fantastic, no probs whatsoever but a bit hard on a carbed bike, so I'll shut up and go away!:fou:

[Blah blah]

Daft question, aren't carb heaters designed to fix this ?? :confused:

I've got an awful lot of oil plumbing, and a switch to divert the oil from the cooler to the carbs, which seems a lot simpler than adding an additive...

[Zimbo]

The oil heaters were an attempt to fix the problem and do help a bit, but don't actually solve it by any means. To solve it you'd have to warm and dry the air as it passed through the airbox rather than just warm the float bowl a little. Pro FST really is the only fix!

[alan c]

how much pro fst should i add to tank full off petrol ?
i had same problem in the cold damp mornings last week, got myself some fst
after advise on thread, no mixture amount on bottle !

[Adam E]

Ive got some fst on the wat so i'll gove that a go, i'll put some new plug in as well....every little helps after all

[Scotty]

add some to the fuel
1% or 2%

i keep useing about 150 ml of the pro fst stuff

it's on their website

[nik_the_brief]

Having run a carbed 600 for several winters, I found carb icing has sod all to do with ambient temp being below zero - more to do with humidity. Mine ran ok on some very cold but dry days, only to play up on a 3 or 4 degree day in the rain.

Tried several fixes - the only one that worked was Silkolene Pro FST

^^^
What Gary says - Pro FST is the mutts nuts for carb freezing. My old 600 was a beggar for it and it was the only cure that worked (though surgical spirits in similar quantities works at a pinch).

I put about 200ml per full tank which is just over 1% and it works for me. Not sure if the 900 is as bad for carb freezing as I never gave it the chance to show me. As soon as it got nippy I started using the remains of last years bottle.

Cold, 'freezing' fog conditions are the worst for carb freezing. You get that a lot at the top of the White Cliffs of Dover so I speak from experience as it's may daily commute.

[gary tompkins]

Best carb freezing 'fun' I had was mid December 1999

Came off the M20 at Swanley & up slip road at about 70mph

Bit wet, quite cold but not freezing & dark, closed the throttle an nothing happened - carbs had frozen open. Pulled clutch in, hit kill switch and coasted to a wobbly stop on hard shoulder... an interesting & pretty scarey 3o seconds :eyepopping:

Invested in some Pro Fst & clean underwear shortly afterwards :D

[Chaos Inc.]

I stock Pro FST for winter but the great joke is I end up buying most of it for my bike. I use about 200ml per tank. More like glup, glup, glup .... mmmmm.... yeh, that seems about enough. Does the job.

All hail the 600 [non-heated] carbs. 'or not'

[Thumper]

Well after buying a can of....

http://www.nulon.com.au/images/large/syb350.jpg

The Monster seems to run fine :chuckle:

Seriously, got some Pro FST yesterday, added it to the bike last night and it started great this morning. I'll keep using it for every tank of fuel right through to warmer conditions next year as it seems to have done the trick!

Thanks :D

[Scotty]

oooh 24% ether eh

best have a look at my book of fuels

[gary tompkins]

Scotty,

I'm sure the 'burds' drink it in clubs up your way?

Splash of vodka & a red bull - sorted :mand: