top of page

Tech Tip: Remove the Stock Inlet Fuel Filter

Updated: Feb 10, 2021

This is a really quick tip: just throw that "clog fest" in the trash!

Avoid potential fuelling issues, this is a must check on any "new to you" bike.

Inlet fuel filter on the BST40 carburetor on a DR650

The issue

Suzuki deemed a good solution to place a ridiculousy small fuel filter hidden away inside the carby inlet.

You might not even know it is there and this is precisely the issue!

You can't see it, it is hard to get to and the filtering surface is really small.

In a nutshell, it can become a potential issue at accumulating debris over time and gradually clogging up the fuel flow because of a lack of maintenance.

NOTE: Like most bikes, the bushpig has a first fuel filter on the petcock itself.

This is the first line of defense against foreign materials that would come with the gas or get into the tank. Whether you have the OEM tank or a larger capacity one, it's worth checking this filter once in a while and/or do a rinse on your tank if necessary.

This is the OEM petcock, it has actually two filters. The highest one is your "ON" position and the lowest one is the "RESERVE" position.

Aftermarket petcocks like the ones coming with Acerbis tanks are built differently.

They use a single, tall and wider filter fitting over the brass tube and the hole at the bottom.

And they do not use a vacuum line to shut off!

The solution

Remove it and use a quality inline fuel filter instead.
  1. Close the petcock (if aftermarket one) and detach the fuel line from the carby

  2. Use a knife/small flat screwdriver to pry the filter rim up a little (it's in there pretty tight!)

  3. Use some needle-nose plier to finish extraction

  4. Connect the fuel line back on

  5. Locate where the new filter should go and remove its length from the line.

  6. Connect the inline fuel filter and secure with fuel line clamps

The little tiny bastard was quite gunked up!
Tiny bastard VS the new filter and fuel line clamps

As you can see above, the OEM filter is really tinny and because of its shape, there is really only the tip being used as a filtering surface.

This one comes from a bike with 38 000km and was starting to get pretty clogged up!

What supplies to use?

  • Preferred fuel line is thick automotive type in 5/16", not the clear thin wall

  • Small with transparent body gas fuel filter in 5/16" as well

  • Use spring style line clamps, not zip-ties!

Note: The carburetor inlet size is 5/16", so we prefer going with the larger size rather than the more common 1/4".

Aftermarket inline fuel filter under an Acerbis 5.3 gal. tank

Et voila! You now have a simple and reliable filtering system, easy to check, easy to replace and giving you good feedback is gas is flowing or not!

Note: This "disc" style filter with the Acerbis 5.3 gallons will always show half full due to the horizontal position (the larger tanks come much lower than the OEM).

It does work perfectly and has no influence on gas flow, you can actually see it even better.

Also, in order to get a better fuel line routing, yes you can turn the carby inlet forward!

Its press-fitted in there so take extra care in doing so, it's quite hard but it will turn. Just use an adjustable wrench to apply torque on the pivot itself.

Available in the store: Mini disc fuel filter on it's own and a full Fuel Supply Kit that comes with all you need to fit your aftermarket tank.



bottom of page