Should you turn off the fuel tap on bikes

[landuse]

Hi there. I have a question. With motorbikes I have heard that it is recommended that each time you finished riding, you should turn the fuel tap off. If you don't, it apparently hurts the carb or something.

I have just bought a bike, and I was wondering if this is true. What are your thoughts?

 

[Rustydog2010]

It all depends on its condition really.

Like my bike has a slow leak from the carb, so I turn the fuel tap each time. If the bike is in good condition and you use it on a regular basis it should be okay to leave it on.

If you are going to park the bike up for say, the winter. I would make sure I drain the carb and turn the fuel tap off. If its left for to long the fuel will go stale. I normally just top it up with fresh fuel and its okay. Thats just IMO.

Someone else with a bit more experience will be able to chime in.

Jeremy.

 

[landuse]

I just bought myself a new Suzuki EN125. I basically just use it to get to work and back. The price of petrol is killing us here. I can get about 35-40KM/litre with this baby. It is brand new, so the carb is still good.

 

[HellSpawn]

Personally, if its easy to shut off, might aswell. Helps ease the mind that if your bike is going to spring a gas leak within the carbs, its not going to piss out all of your gas on the ground overnight.

On my CM, I actually turn the fuel off a few minutes before I get wherever i'm going so it'll burn up all of the gas in the carbs. They have leaked before, but I eventually made a new set of o-rings for the fuel crossover tube. But I still worry about it leaking again if I forget to shut off the fuel

 

[anderkart]

Hi there. I have a question. With motorbikes I have heard that it is recommended that each time you finished riding, you should turn the fuel tap off. If you don't, it apparently hurts the carb or something.

I have just bought a bike, and I was wondering if this is true. What are your thoughts?

It wouldnt hurt the carb but the issue is just that sometimes the fuel system might develop a leak, or the needle and seat valve inside carbs can sometimes get a small bit of dirt keeping the valve from sealing closed. If that happened while the engine was running, the fuel flow and vibration would many times clean/flush that bit of dirt on through into the float bowl and cause no immediate problem.

But if your needle and seat valve was failing for whatever reason while the bike was parked, gravity would carry the fuel down from the tank and fill up the carb until fuel ran out the carbs vent. Given enough time this would completely drain your tank all over the ground causing a pretty serious fire hazard besides leaving you with an empty fuel tank.

Shutting your petcock off every time is a really good habit to get into with motorcycles, It might not be necessary every time but sooner or later you'll be glad you did.

 

[newrider3]

Even a carb in perfect working order will pour fuel out the vent tubes if you leave the petcock turned on for a long period of time.
Plus, if you don't turn it off after every ride, you don't get the fun of forgetting to turn it on again and wondering why the bike won't start.

 

[landuse]

Plus, if you don't turn it off after every ride, you don't get the fun of forgetting to turn it on again and wondering why the bike won't start.

LOL. That has happened to me a few times now. It is so frustrating. You are in the middle of traffic trying to reach down and turn the petcock back on while still trying to keep your eye on all the cars that 'don't see you'.

Don't you hate it that cars just have no respect for people who ride bikes. I even came across THIS website the other day that tries to educate car drivers about bikes on the road.

 

[anderkart]

Besides not respecting motorcycles, a lot of auto drivers just plain dont see motorcycles approaching because they're so dang small. Even if they see you approaching the narrow profile throws off their sense of depth perception regarding how fast your approaching. That's why speeding on a motorcycle is way more dangerous than with auto's.

Something I found that helped was to always have your headlight on during daytime riding and repeatedly flash from low to high beam anytime you get the feeling a car might not realise your approaching. This easy little trick has probably saved my life several times.

SA. drives on the left side of the road, correct?
If so, making right turns at busy intersections will be one of the most dangerous things you do on a motorcycle. So when possible try to plan your trips to make as many left hand turns as possible.
Just remember, 3 left turns can sometimes = a right

Also try to adjust your speed to enter green-light intersections along with 1 or more cars. The cross traffic will have a much better chance of seeing those other cars than you...

Another thing, as your riding along on wider roads next to other cars, try to stay out of their mirrors blind spots in case they dont see you and suddenly swerve over into your lane. Either stay a little behind the other cars, or quickly pull up past they're drivers door so they'll have a much better chance to see you there next to them.

 

[sexyvicta]

loud exhaust helps in traffic

i always used to follow this tlr1000 with a super loud exhaust lane splitting down the motorway on the way to work.

cars got out of his way real quick lol

 

[Gillgamesh64]

You should always turn the tap off on a two stroke bike, or they can siphon your whole tank onto the ground....

 

[landuse]

SA. drives on the left side of the road, correct?

Thats right Anderkart. I was over in San Diego for a conference a year or so ago, and I nearly got flattened a few times trying to walk across roads. I kept on looking the wrong way before I walked. It took a bit of getting used to.

 

[sideways]

You should always turn the tap off on a two stroke bike, or they can siphon your whole tank onto the ground....

I don't see how that is possible?

As long as you needle and seat seal well and the bike is on reasonably level ground I see no reason why you would have to turn it off.

Good luck with your new bike.

 

[Gillgamesh64]

Well technically you are rite, But I have lost more than one tank of fuel with more than one bike like this, It is simple on occasion you can get a bit of junk in the carb causing the float or needle to stick and the bowl fills and than runs out the overflow, even though a tap on the bow will normaly fix it unless there is more issues with the float or needle.....

 

[Gillgamesh64]

It might not be that cruicial on a new bike but older bikes things can wear, I have only ever owned dirt bikes also so maybe it is not all that common with roadies??

 

[Bluethunder3320]

It might not be that cruicial on a new bike but older bikes things can wear, I have only ever owned dirt bikes also so maybe it is not all that common with roadies??

same kind of carbs really...

every engine i work on (lawnmower, leaf blower, clone engine, generator,)

i always turn the fuel off before putting it away and let the engine burn up whats left in the bowls.

wouldnt it being dry help extend the life of gaskets?
seals?

i have seen some engines, like the 13.5hp i got, that is only 7 years old but the carb seal was completely deteriorated, and there wasnt a shut off on that tank.

^^^^why would that be?

of course keeping it dry must be more than a good thing than bad.

 

[Doc Sprocket]

i always turn the fuel off before putting it away and let the engine burn up whats left in the bowls.

I consider this a good practise, and I do it every time, religiously. Saves me a lot of carb jobs.

 

[newrider3]

I consider this a good practise, and I do it every time, religiously. Saves me a lot of carb jobs.

This may be a good idea for 4-stroke industrial engines, but you NEVER want to run a 2-stroke bike engine out of gas.
As soon as the mixture starts to lean out, the motor starts 'Dieseling', and there is no way to shut it off (besides possibly dumping the clutch in gear to stall it).
Then it will death-rev until some sort of failure.

 

[Bluethunder3320]

LOL

are bike engines just more prone to that?

because when i used to be in the r/c car hobby and those 2 strokes you pinched the fuel line to shut them off, and usually they revved up a lot and died, but it was a pretty short time that it would do this.

the other way was to plug the exhaust since the gas tank vent was fed by the exhaust, this pumped tons of fuel into the engine to stall it.

since they ran on glow plugs there wasnt any electrical system on the engine.

 

[Doc Sprocket]

This may be a good idea for 4-stroke industrial engines, but you NEVER want to run a 2-stroke bike engine out of gas.
As soon as the mixture starts to lean out, the motor starts 'Dieseling', and there is no way to shut it off (besides possibly dumping the clutch in gear to stall it).
Then it will death-rev until some sort of failure.

Point taken. I was referring to 4-strokes. I probably should have specified.

 

[HellSpawn]

This may be a good idea for 4-stroke industrial engines, but you NEVER want to run a 2-stroke bike engine out of gas.
As soon as the mixture starts to lean out, the motor starts 'Dieseling', and there is no way to shut it off (besides possibly dumping the clutch in gear to stall it).
Then it will death-rev until some sort of failure.

this happened to my YZ400 at one point in time, scared the **** out of me too.