Preventing Petrol Porridge

Life Cars & Motorcycles
1

Is there any downside (apart from having to wait for it to refill it again) to draining one’s (motorcycle) carb and leaving it dry if one doesn’t use the machine very often? Petrol seems to go off very quickly here and sludges up carburretors in no time.

Both the Mikuni carbs I’ve got have a drain screw, so (with the petrol tap closed, of course) could fairly easily be left dry, but I don’t know how the materials stand up to that corrosion/wear/perishing-wise, though I wouldn’t expect any problems.

One could squirt WD-40 or light oil in the fuel line I suppose, but having to detach that would make it a bit more of a chore.

Intelligent speculation/opinion or (even better) actual experience welcome.

Oh, some of you probably call petrol “gas”. I can’t help that, and I suppose you can’t either.

2

Ed, I have more information than you ever wanted on storage. This comes from my Stateside club, the Ninja 250 Riders Club. They think it’s a really good idea, although I can’t vouch for whatever negative effects the climate here may have. The hard part might be finding fuel stabilizer, to keep what’s left in your tank from going off, too.

And yes, I know the EX/GPX/Ninja 250 is a ‘beginner’s bike’, but most of the FAQ contributors have been riding for years and just like small bikes, at least sometimes. And I think we usually use the work “fuel”. Hope that’s OK :smiley:

The second article is basically the first one with pretty pictures.

faq.ninja250.org/wiki/How_should … storage%3F

faq.ninja250.org/wiki/Winter_sto … hoto_essay

3

[quote=“Bokonon”]

And yes, I know the EX/GPX/Ninja 250 is a ‘beginner’s bike’, [/quote]

Not here it isn’t. Anyway, thanks a lot for the info.

On balance I’m reassured, though its also been suggested to me that a dry carb might corrode internally if Taiwan’s atmospheric humidity got to it, so I dunno, I suppose giving a squirt of WD-40 might be extra insurance if one was going to leave it for a while.

Trouble is I never THINK I am going to, and then other shit happens and suddenly its been standing for months.

4

I sometimes don’t ride a given moto for over a year (stored in various remote places). Fuel stabilizer and running the carb bowl dry after adding and mixing the stabilizer have always worked. Last week I had a plated XR650R, not started in a year, start on the first kick. If you’ve ever kick-started an XR650R, you’ll know how joyful that moment can be. No Button. Very high compression.

I’m sold on stabilizer. I think one sold under the Seafoam brand is the best.

5

Fuel stabilizer in the tank, carb dry. The o-rings and rubber gaskets in the carb can withstand humid air quite well, and most of them are squished between to hard surfaces and have little exposure anyway. Don’t use WD-40. Much of it evaporates quite quickly and the deposits left, while nicer than dying fuel, are also able to clog the small passageways in the carb.

Petrol? Gasoline? Gopferdammi! BENZIN!

:laughing: :unamused:

The tips from the Ninja guys are spot on regarding oil / filter changes. As the oil in a 4-stroke engine ages it is contaminated with combustion gases that escape past the piston rings. Once dirty it contains some acid compounds which if just in contact with some metals used in plain bearings, could eat at the surface on a microscopic scale. No it’s not alien blood aggressive but with enough time it can cause early bearing failure. Note this applies only to 4-strokes. 2-stroke motors have enough sticky oil in the engine itself to protect it for a winter and the oil in the transmission cases is not exposed to combustion gases.

One other thing to look for is your wildlife population. If you have mice or other small animals that try to hibernate where you live, you may want to block the intakes to your air filter box. I know a few people who’s motors have woken up from their winter sleep with a breakfast of mouse! :laughing:

Oh, and for those who stumble onto this thread with a carb that’s already choked with sludge: Do NOT attempt to clean fuel or air passages by poking things in them. You could easily ruin it. Always use carb cleaner and high pressure air.

6

Here below is some parallel chat pasted over from a PM thread. I thought it was relevant, but that I should respect the other parties wish for privacy by keeping them anonymous.

I don’t find the stated unavailability of fuel stabiliser in Taiwan very surprising, given the lack of a “maintenance culture” here, though it is a little sad.

Arising from that, if WD-40 is a bummer, how about 2-stroke oil, either in the tank, or just a bit in the carb? It’ll run a bit smoky of course on re-commissioning, but hey, this is Taiwan.

Ducked wrote:
Wouldn’t oil (or WD-40) do for the carb if a preservative is necessary? It wouldn’t protect fuel in the tank, but my impression (and its nothing more than that) is that carbs clog a lot faster than the fuel in the tank goes off.

This may be because the smaller volume of fuel involved dries out faster, but I wonder if there isn’t some catalytic or adsorbtive effect involved with the largish contact area in the carb. I don’t know what the chemistry is but I get preponderantly a grey sludge adsorbed on the casting surfaces, not the varnish residue thats usually described.

How do 2-strokes, particularly those using premix, compare for fuel system sludging and corrosion?

Anonymous Reply:

Although I love WD40 myself for everything I cannot confirm or deny any of your questions here sorry.

Although leaving a metal gas tank empty can certainly result in rust but I think you intend to leave fuel in the tank anyway…

I like the idea of the running the stable fuel through the system because it gets into those hard to reach places throughout the system.

I have never in my life noted this problem as a specific fuel decay problem so I couldn’t answer on the 2 strokes, perhaps it either passes through and gets spat out the exhaust or I have just cleaned the carb not caring where the muck came from since off road we are exposed to so much muck on river crossing and riding on so much dust, dust and dirt that inevitably what ends up in the carb is brown muck haha.

Is it possible that 2-stroke oil acts a stabiliser, I don’t know it would be interesting to research. But I would still like a stabiliser for my car and scooter.

I have spoken to my friend who works at car magazine and he says there are no stabiliser products in Taiwan, thats sad and hard to believe but if I can’t find one I may just import some.

7

Small animals PAH! I had RATS!!! (well, at least one) nesting in my car engine compartment last year, during a period of heavy rain. Scared the shit out of me. Slammed the bonnet (hood) down, came back with a big stick and beat the bonnet (hood) with it for a minute or two before VERY cautiously opening it up.

Got some “crazy foreigner” looks from passing locals, who probably hadn’t seen John Cleese do basically the same thing in “Clockwise”.

8

Well, the lack of a winter in Taiwan might also be a factor…

[quote]Arising from that, if WD-40 is a bummer, how about 2-stroke oil, either in the tank, or just a bit in the carb? It’ll run a bit smoky of course on re-commissioning, but hey, this is Taiwan.[/quote]Synthetic two-stroke might be more stable than gas, but still, it will not stop the fuel itself from deteriorating. Remember that a reasonable ratio of 2-stroke mixed with gas should foul plugs or cause detonation in 4-strokes, but it is not good for catalytic converters.

[quote]
Ducked wrote:
Wouldn’t oil (or WD-40) do for the carb if a preservative is necessary? It wouldn’t protect fuel in the tank, but my impression (and its nothing more than that) is that carbs clog a lot faster than the fuel in the tank goes off. [/quote] I think it’s just the quantities we are talking about. It takes a tank full of gas longer to go off, but it does if left long enough. I do notice that a vehicle left outside will have bad fuel in the tank before one in underground parking. I think temperature has a lot to do with the breakdown process.

[quote]

How do 2-strokes, particularly those using premix, compare for fuel system sludging and corrosion?
[/quote] The only 2-stroke bikes I have experience with that run premix were all race bikes. Race fuel is especially unstable so the trick there is to buy just much as you need for a weekend, and mix it with oil to make enough premix only for a day of racing. Any that isn’t used up on Sunday is disposed of.

[quote]
Although leaving a metal gas tank empty can certainly result in rust but I think you intend to leave fuel in the tank anyway…[/quote] Most of the problems with rusty fuel tanks in Taiwan comes from the water they sell you mixed in the gas. I put about 5% of the fuel mass of methanol in my tank once a year. It’s hygroscopic, soaks up the water, allowing it to be burnt with the fuel instead of laying in the bottom of the tank. You can buy methanol in many places.

[quote]
Is it possible that 2-stroke oil acts a stabiliser, I don’t know it would be interesting to research. But I would still like a stabiliser for my car and scooter.[/quote]
AFAIK 2-stroke oil is no stabilizer, though I doubt it would hurt any. I would drain the carbs and fill the gas tank to the top with a mix of gas and methanol for long storage if no stabilizer were available. More importantly I would store the vehicle in underground parking if at all possible.

9

I’ve read somewhere (in the context of alternative fuels) that methanol can corrode the aluminium in carbs. Shouldn’t be a problem in the (steel) fuel tank (if the carb is drained) and perhaps a low concentration isn’t an issue when you burn the fuel either.

Here’s a Wikipedia (so it must be true) entry. http://en.wikipedia.org/wiki/Methanol

I’ve got no reason to disbelieve the chemistry but its hard to judge how important (severe, fast) it would be in practice.

"One of the drawbacks of methanol as a fuel is its corrosivity to some metals, including aluminum. Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion:

6 CH3OH + Al2O3 → 2 Al(OCH3)3 + 3 H2O
The resulting methoxide salts are soluble in methanol, resulting in clean aluminum surface, which is readily oxidized by some dissolved oxygen. Also the methanol can act as an oxidizer:

6 CH3OH + 2 Al → 2 Al(OCH3)3 + 3 H2
This reciprocal process effectively fuels corrosion until either the metal is eaten away or the concentration of CH3OH is negligible."