Petrol Life

RON1953 · Jul 7, 2009

Hi,

I have a 1970 commando with standard concentrics, unfortunately it doesn't get used regularly, but after a run with fresh petrol in if I leave it standing for a month no way will it start, drain the tank put fresh petrol in and it starts first kick. what can be done to make it less sensitive, or is it the UK petrol.

Cheers
Ron

cash · Jul 7, 2009

Never had that problem with UK petrol even after the winter layup.

Do the carbs flood OK when tickling? coz sometimes they do air lock, open both taps and you might hear the air bubble out.

Try hotter plugs, carbon fouling can cause poor cold starting.

Cash

bigstu · Jul 7, 2009

When you drain the petrol from the tank do you drain the float bowls in the carbs as well?

swooshdave · Jul 7, 2009

bigstu said:
When you drain the petrol from the tank do you drain the float bowls in the carbs as well?

Before you put the bike away, start the bike and turn off the fuel taps. When the bike dies the bowls will be empty. Might make it easier to start the next time.

BrianK · Jul 7, 2009

Actually, they won't be empty, they'll just be at the point where the fuel levels are too low for the suction to pick up. I'd pull and drain them. And/or use SeaFoam in your gas tank (and run it so it mixes and gets in the bowls), which will both stabilize the gas and help clean your carbs and lines.

swooshdave · Jul 7, 2009

BrianK said:
Actually, they won't be empty, they'll just be at the point where the fuel levels are too low for the suction to pick up. I'd pull and drain them. And/or use SeaFoam in your gas tank (and run it so it mixes and gets in the bowls), which will both stabilize the gas and help clean your carbs and lines.

True, but they'll be low enough so that gas doesn't get clogged in the pilot jet when it dries up and turns nasty.

L.A.B. · Jul 7, 2009

Ron,

Always empty the float bowls if you won't be using the bike for more than a couple of weeks, as the fuel in the float bowls tends to 'go off' more quickly than the tank fuel.

BrianK said:
use SeaFoam in your gas tank

I'm not sure that "SeaFoam" is commonly available in the UK? However there are other brands of petrol stabliser that Ron could use such as Motorex http://www.mandp.co.uk/productinfo/5028 ... es/Motorex (or try your local garden or mower centre, Ron).

ML · Jul 7, 2009

Hi Ron,

Does your bike have open carbs? If so and you're storing the bike in a damp shed it not uncommon to have condensation collect in the carbs which will effectively block or impede proper starting. Draining the bowls after a long lay up is a good thing to do. Periodically squirt some quality carb cleaner in all jet passages too.

Mick

RON1953 · Jul 8, 2009

Thanks for the suggestions, the only thing I haven't tried is additives, It's taken a long time to find out about the petrol, so I've tried most things, I,ve stripped the carbs,replaced all the jets,warmed the plugs over time to get it going, then soon as I put clean gas in, first kick, what are the best plugs to use, are the iridium ones worth a try.

Ron

kanaka · Jul 8, 2009

also try opening the petrol cap after it has been sitting for a while incase the tank is not venting

Petrol Life

RON1953

cash

bigstu

swooshdave

BrianK

swooshdave

L.A.B.

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ML

RON1953

kanaka

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