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Hey what’s up everybody, it’s Matt from
HowToMotorcycleRepair.com. In today’s video, I want to show you common fuel leaks that may develop on motorcycles. Fuel leaks are very unsafe and dangerous,
so if you walk out to your motorcycle and smell or see gasoline, do not attempt to start
or ride the motorcycle. If you are riding your motorcycle and you notice a fuel leak, park the motorcycle immediately! Turn the fuel shut off valve to the off position and make sure the area is well ventilated. There should be no ignition sources or open
flames in the area. Wipe up any fuel with rags, and then lay them outside
to dry so the fuel can evaporate. Once dry, place them in a sealed container
and dispose of them properly. Before we begin discussing these repairs,
I do want to mention that if you are unsure or uncomfortable with anything mentioned in
this video, please seek professional help and have it repaired properly. Now if you are going to tackle this yourself,
make sure you’re wearing safety equipment. I always wear safety glasses and gloves. Make sure to have a fire extinguisher nearby
especially when fuel is involved. It is also a good idea to have the service
manual for your model so you can look up certain specifications. Do not begin any work until the engine and
exhaust are at room temperature. One source of a fuel leak may be from the
fuel lines. Repairing fuel lines is an easy repair that
any DIY’er can tackle. Fuel lines can become brittle, and may crack
over time. Go ahead and bend a section of the line to
see if the material is still pliable and visually inspect them for cracks. If the fuel lines seem questionable, it would
be a good idea to replace them. To remove fuel lines, make sure the shut off
valve is in the OFF position, remove any clamps, and pull the lines off with your fingers or
a set of pliers. As for replacements, make sure you use hose
that is rated for fuel, and it is also the correct size. Many motorcycles will use metric sizes, so
you may need to head over to your nearest motorcycle dealer for replacements. Here is a quick tip, use the old line to measure
cutting your new lines. Also, replace the fuel lines one at a time
if you have multiple lines. That way, the right connections will be maintained. Make sure to reinstall hose clamps at all
connections. Similar to fuel lines, gaskets in the fuel
system become brittle and may crack over time. In my experience, the most common gasket to
fail is the carburetor float bowl gasket. Replacing this gasket will require an intermediate
skill level. You can spot this leak by looking at where
the carburetor and float bowl meet. To replace this gasket, go ahead and drain
fuel from the carburetor. Next, remove the carburetor. Carburetors have very small parts inside,
so it is always a good idea to start with a clean and well lit work area. I like to use magnetic parts trays to hold
all the small parts and fasteners. Disassemble the float bowl, which usually
is held on with 2 to 4 screws. With the float bowl removed, inspect the gasket. Use a pick to help remove the gasket. Here is a quick tip, apply a few small dabs
of grease into the groove in which the gasket lies in. This will temporarily hold the new gasket
in place during assembly. Go ahead and install a new gasket. Make sure to wipe up any excess grease. Reinstall the float bowl and tighten the screws. Reinstall the carburetor and check to see
if your leak is gone. Now let’s move on to the most common cause
of fuel leaks, and it’s due to this little part right here, the float needle. It is common knowledge how problematic this
part is, and requires an intermediate skill level to repair. This float needle regulates flow of fuel into
the float bowl. When the bowl is empty or low on fuel, the
float drops down and will open the needle valve so more fuel can enter. As the bowl fills up, the float will lift
up and the needle will shut off fuel flow. Since the needle is a moving part, it often
becomes worn and can no longer seal and stop fuel flow. When the needle is worn, fuel continues to
flow and it will either start pouring out the carburetor overflow and onto the ground,
or it may fill the engine and airbox with fuel. To fix this problem, remove the float pin
and float. Install a brand new float needle. Reinstall the float and pin. If the engine or airbox became soaked with
fuel, make sure to check the condition of the air filter and make sure to change your
engine oil. Alright, well I hope you enjoyed that video. If you’d like to see more of my videos,
head over to howtomotorcyclerepair.com or check out my YouTube channel MatthewMCrepair. I’m also on Facebook and Twitter. If you are unsure of anything
discussed in this video, seek professional help. Thanks for watching and see you in the next

16 thoughts on “Common Fixes When Your Motorcycle Has a Fuel Leak | Allstate Insurance

  1. Amazing Matt. I've a xj400 just bought it off a guy…it was laying up for 6 months. So need to check it. Where did you get that owners service manual. I need one.


  3. Can I take the bottom part of the carb off and replace the gasket without removing the whole thing from my bike? I have 1975 Honda CB750 and it appears that the 1st carb is seeping a little bit. Not sure exactly from where, but the side of the carb will get wet from gas and occasional a drop or two will end up on the engine below. I've had a couple mechanics tell me not to worry about it, but it seems like something I should deal with.

  4. I have a fuel tank with a fuel tap just like that (with the nut/screw fixing to the tank)
    I have completely stripped the paint and there are no holes in the tank, repainted it 3 times now because the fuel leaks out of the tap connection and ruins the paint work again.
    I have bought a brand new OEM replacement tap, filter and o-ring seal. Im slightly hesitant to put it on incase it damages the oring.(cant seem to find the one that fits without buying a new tap?!?)

    My question is, what are the things to look out for when servicing that area?

    Thanks in advance.

  5. AWESOME! You could be a college instructor, very well presented! Plus, I'm pretty sure these carb kits I ordered will fix my fuel problem for sure.

  6. Can you try and explain to me why whenever I move my dirt bike petrol leaks from the outsides of the petrol cap ?? Seems that it’s such a simple but uncommon problem there are no videos about it, should I simply buy another petrol cap or is it because my tank is too full ?

  7. If your fuel valve does not have an OFF position but instead has a PRI or PRIME position, READ THIS BEFORE YOU ATTEMPT TO FOLLOW THIS VIDEO'S INSTRUCTIONS.

    There's something this video doesn't cover, and it can result in serious damage and injury. It's downright irresponsible to NOT cover this. When the video talks about shutting the fuel off on the valve, it shows putting the valve in the middle position, marked "off". This is fine, if there's an off position. But what if your valve has one marked "PRI" or "PRIME" where the OFF is on the valve in the video? Well… DON'T SET IT TO PRIME. Instead, LEAVE IT in the ON position.

    See, here's the thing. If the valve has an off position, the fuel is fed into the carburetor by gravity and gravity alone. That is, any time it's set to ON or RES, fuel will flow if there's anywhere for it to flow too. However, if it has a PRIME setting, then in the PRIME position, the fuel will flow like with the other type if it's set to ON or RES. However, with a PRIME setting, if it's set to ON or RES, the fuel will ONLY flow if there is vacuum.

    With a valve that has a PRIME setting, there are two hoses that attach to the valve. The fuel line and the vacuum line. When the engine is running, the pistons moving creates a vacuum. Using a vacuum line attached to one of the vacuum nipples on the carburetor(s) that goes to the vacuum nipple on the valve, the resulting vacuum is transmitted to the valve and causes the valve to release fuel. Unless there is vacuum, no fuel will flow in the ON or RES positions.

    Because of this, the carburetor bowl will eventually dry out if the valve is not left in the PRIME position. This has the benefit of not wasting fuel and also limits varnishing of the carburetor bowl and needles. However, it means that if the engine is not run for a sufficient length of time, the carburetor bowls will be bone dry and the engine will not start.

    Running the starter motor WILL cause some fuel to flow into the carburetors, but it's just as likely to wear out your battery and starter motor. This is what the PRIME setting is for. It allows fuel to flow into the carburetor without a vacuum. So what you would do is set the valve to PRIME for 5 minutes before you attempt to start the motorcycle. This gives sufficient time for the fuel to fill up the bowls and you'll be able to start it with a lot less cranking. Once it's started, it's a good idea to set the valve back to the ON or RES positions.

    So as you can see, if you have a vacuum actuated valve, then the ON or RES position is functionally equivalent to OFF when the engine is not running. You can however install a shut off valve in the line so that it won't get fuel even when the engine's running, but why though?

  8. ATTENTION READ THIS, another problem he did not mention that is very easy to fix is the float getting stuck, all you have to do is hit the float bowl with a screwdriver/hammer a few times. Try that before buying anything always works for me

  9. I have a Honda xr80r and I was wondering if you put the setting “fuel on” next to the choke while your riding? Plz reply

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