Fuel Taps/Solenoids

charlie said:
If not, just wondering what the effect of leaving taps on really is, and the cure? Can't find a description on the forum.
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First thing is to pill the spark plugs and turn the motor over to find out if the cylinders have fuel in them ....... if they do then you will want to check your oil to see if it is saturated with fuel.

Not removing the plugs before turning over the motor could lead to one or both cylinders "hydro-locking" and this could cause catastrophic damage. Oil saturated with fuel should not need any explanation as to what could happen or what you should do next.

Jim
 
Thanks Jim, that fills me with cold fear after just getting the top end done by Keith. I was due to change the oil anyway, so I guess I can do that 'cold' in any case. With plugs out, I fire the starter, and look for what? If there's fuel it will be spraying out of the plug holes?
 
charlie said:
Thanks Jim, that fills me with cold fear after just getting the top end done by Keith. I was due to change the oil anyway, so I guess I can do that 'cold' in any case. With plugs out, I fire the starter, and look for what? If there's fuel it will be spraying out of the plug holes?
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Be careful where the sparks go when you crank the engine over and it's spitting fuel.
You'd be surprised at how quickly a Laverda burns.

Paul
 
OK, so we are talking spitting fuel (though I hope not). Spark plugs out of leads makes sense then. I am hoping 3 months layup can't cause this on a recently fettled engine, but what do I know.
 
charlie said:
OK, so we are talking spitting fuel (though I hope not). Spark plugs out of leads makes sense then. I am hoping 3 months layup can't cause this on a recently fettled engine, but what do I know.
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Using the kill switch will do.
Take the plugs out and have a look. Drain the oil to see if it's full of petrol after 3 months. If not, you should be ok.

You'll just have to clean the carbs. At least the idle jets.

Paul
 
Thanks Paul, I will look over the weekend if the weather above ground is ok. I've had a read of your website. Who do you rely on in France for Laverda work? (Mine has been to Breganze once – I'm in the Alpes.)
 
charlie said:
Thanks Paul, I will look over the weekend if the weather above ground is ok. I've had a read of your website. Who do you rely on in France for Laverda work? (Mine has been to Breganze once – I'm in the Alpes.)
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There is nobody in France.
I try to do it all myself, apart from cranks, rebores and more specialist engineering work.

Paul
 
Open taps risk the chance of flooding/overflowing and filling one or more cylinders with fuel. On start-up, a hydro-lock may occur and a conrod may be bent or the crank phasing altered, both not very favourable. A low battery or weak starter might prevent this to a degree...

Due to the quite extreme angle of the carbs, the float valves have a hard time closing off the fuel flow reliably. The taps themselves are far more reliable in this respect.

I once drained 18 litres of "oil" from the sump of a long-standing triple, parked over winter with a full tank and open taps. Needless to say, the tank was empty and the cylinders full to the brim. Another 3 months and the cylinders would have emptied themselves. ;)

piet
 
Doesn't help that I recharged the battery and had another go then...

Any idea how rapidly this can occur: would 3 months be considered a short term or long term leakage, which I presume affects severity?

Also if I do find petrol in the cylinders/sump, can I change the oil and attempt a start? I'm guessing not, but stripping the bike to 'see' if anything is amiss is painful to think of after it's just been done.

Hopefully won't be necessary, and this info will add to the always-turn-off mantra. 20 years doing it myself, hope I didn't *uck up this once.
 
All depends on overall condition of your float valves, and/or how clean the fuel and carbs are.

Easy as... remove all plugs and turn the engine over, with ignition disconnected. If the cylinders are filled, it'll result in a bit of a mess, the last you need is a stray spark to set your bike alight. Place a large rag over the plug holes to limit the mess. Keep a bucket of water or an extinguisher close to hand. Oil can simply be changed if contaminated, the fuel that will have seeped to the sump might even help wash out bits of crap that would otherwise remain inside, so there's even an advantage in it. ;)

piet
 
Many thanks Piet. Keith also refurbed the carbs, plus 3 new float valves fitted. Petrol was fresh and full.

That is one fun-sounding cleanout procedure :-( Ignition disconnected, what's the best way. Kill switch off not good enough?

And if this is the scenario, once cleaned out, I can risk turning it over with fresh oil to see if there's internal sounding damage?...or it starts.
 
I'd squirt some oil through the plug holes and turn over a few times before starting. Bores and pistons will be quite dry if fuel has seeped through.

New float valves are no guarantee. They certainly help, and are often necessary, but still not 100% reliable, never have been.

Kill switch off, engine won't/shouldn't turn, on the button at least.

piet
 
charlie said:
Many thanks Piet. Keith also refurbed the carbs, plus 3 new float valves fitted. Petrol was fresh and full.

That is one fun-sounding cleanout procedure :-( Ignition disconnected, what's the best way. Kill switch off not good enough?

And if this is the scenario, once cleaned out, I can risk turning it over with fresh oil to see if there's internal sounding damage?...or it starts.
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I'd keep the ignition off. With plugs out you should be able to turn the motor over by putting it in a high gear and turning the rear wheel by hand. It'll spin slowly without spitting fuel everywhere.
 
Odyssey was low and drained very quickly when I first tried to start it a few days ago (very cold winter). Charged it and it turns better, but no joy. Need to find someone to test it properly as first step... still suspect it's the culprit.
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Unless I missed something, Charlie, does your comment above imply that you have actually had the engine turn over on the starter? If so you can happily forget about 'hydraulicing'. If fuel had leaked past the float valves, you wouldn't have succeeded in getting the engine to move. You'd be very unlucky for that to have happened after Keith fitted new items, although as Piet says, no guarantee!

So I suggest you stick with your original plan. New plugs, fresh fuel (make sure you drain the carbs by removing the float bowl screws), fully charged battery (maybe try adding another with jump leads) and see how that works. Obviously you can try whacking the engine over with plugs removed and earthed before you replace them with new for good measure...
 
Hi Rob, that's true. On second pass with a charged battery I was hearing the starter motor for sure and therefore presumed the engine was turning over but not firing. So hope there.

Oil needs changed anyway. So will go for... ignition off, plugs out, turn real wheel to see what's what...drain and replace oil...drain float bowls, new plugs and fresh fuel. Will await gizmo arriving in a week to check battery condition. And will check fuel level tomorrow as a clue too, believe I left it virtually full. Thanks all, been away from the forum for some time and it's as brilliantly helpful as always.
 
Good on you Rob. I was just about to make the same observation. if you had the motor spinning on the starter already then you have no damage to worry about. Pull the plugs and do the check anyway.

And if it's any consolation in I used my SF for probably 30 years and never used to turn off the fuel taps. I won't be doing that in the future, but it does show that it's not a 'given' that leaving the taps on will cause float flooding. I only experienced flooding on one cylinder once and that was due to leaving the fibre washer out from under the float valve seat after a carb service - the engine 'stuck' and wouldn't turn over so I removed a plug and spun it over, discovering the problem. Even then, luckily, no damage was caused due to hydrolocking.
 
If you leave the taps on and your float needles dont seal right, gas can fill your combustion chambers and fliw into the crankcase. In the worse case if you start the bike it may hydraulic lock....ie the gas prevents the piston from full stroke at TDC and you bend a connecting rod. This is bad and expensive.

If you suspect gas in your engine.....smell or gas coming out the carb overflow vents etc then you need to get rid of the gas before starting the bike. You could try pushing it and engaging the clutch with the key off, to pump it out the exhaust. Or drain the crankcase if you smell gas in the oil or the oil level is now to high as gas is mixed in with the oil. Could also take out the plugs and turn the engine over....with cold engine and no spark.

Better just to turn the taps off. And renew those float needles before they get too hard or worn.
 
Blimey, so many difficult solutions to a simple problem.

If you wanna crank the engine via the starter motor with the plugs out and the ignition disabled (to eliminate the risk of sparks igniting any fuel) just clip a jumper lead from the positive battery terminal to the starter motor cable (where the big wire bolts onto the starter motor).

If you don't have a jumper lead, just disconnect the positive feed to the ignition. It shouldn't be hard to identify, regardless of what type of ignition system you have. If you can't identify the power supply wire, just unplug the entire ignition box(es). You can then hit the starter button as much as you like and there won't be any sparx.
 
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