Inline fuel filter causing problems?

I recently put a new inline fuel filter on my bike and the wierdest thing seems to happen. My bike runs much worse with the filter. With the tank off, a remote fuel supply and no filter, it runs great, smooth rev, good idle but... with the inline filter, it seems to sputter and has a tough time ideling! I got one of those cone shaped filters, it is installed correctly (flow direction) and I just recently rebuilt the carbs and dialed in the float levels. Is there maybe a diferent type of filter, maybe a high flow type I should use. I spent a good amout of time getting my carbs dialed in and dont want to risk having to battle with the airbox and everything else over some minute bit of fuel gunk that could clog them up without a filter. Shoot me some ideas please! Thanks guys!

Could test flow volume through filter by connecting remote tank > fuel line > filter > outside world, and see if gas runs out all over everything. This high-tech test should be of relatively short duration. :lol:

Good Luck!

Am thinking it's this type filter

Inline filter from Z1E

Perhaps the bike fuel tank needs flushing out (remove tank, hold upside down and dump old gas, put in some fresh clean gas, sloush around, hold upside down and dump again). Also petcock tube filter screens up inside tank could be clogged (may remove entire petcock from tank and carefully/gently clean the intake screens, and also clean any other petcock filter screens).

The new inline fuel filter may have already given its life in protecting the carbs from the initial onslaught of incoming crud infestation from the regular fuel tank supply.

Am uncertain whether the conical style filters may be blown clean with compressed air introduced into the outlet side, theory being to blast off the collected crud. But being so inexpensive, would just use a new filter.

Haven't yet experienced getting a "faulty" brand new filter, but would guess it's possible.

Good Luck!

I noted this problem while using a remote fuel sorce. My tank is currently undergoing paint work so was using a remote fuel bottle. It is open ended so it is not creating any type of vacume that would prevent fuel from flowing. The filter you showed is the type but... the intake side of the filter is at a 90 from the out. I got this type to ease the presure on the fuel line from the tank when it is on. I will put the tank on (which is clean) and see if the problem still exist.

Hey Jeff,

You know I had the same problem when I first got my bike. I put the filter inline, and the carbs would starve out. The problem was most prevalent on the freeway, particularly after I was on the gas for any length of time. It seemed that the engine could use more gas then the trickle supply was able to provide.

I got a petcock from a much newer year Suzuki of all things. Converted/upgraded to one that would shut off if there was no active engine vacume to keep it open. (I could check my post archive to find out which if you would like.) It has a much bigger screen on it compared to the old Kaw petcocks, about 3 inches tall and it's depth and width completely fit the aperture of the hole in the tank seemingly maximizing the surface area of the filter = more flow through the screen. And the mounting bolt holes match up nicely to boot. I just had to run a vacume hose from one of the four capped vacume sources on the bottom of the carbs. That helped solve my fuel leaking problems as a bonus.

Now I run no inline filter, allowing the petcock screen to do the job of filtering. I have since had no fuel flow problems. It took me weeks and many different fuel line/filter configurations to finally find a fix that worked.

Add one more viable option to the list man. Best of luck with the projects.

jrjstuff wrote:

I noted this problem while using a remote fuel sorce. My tank is currently undergoing paint work so was using a remote fuel bottle. It is open ended so it is not creating any type of vacume that would prevent fuel from flowing. The filter you showed is the type but... the intake side of the filter is at a 90 from the out. I got this type to ease the presure on the fuel line from the tank when it is on. I will put the tank on (which is clean) and see if the problem still exist.

There are only a few things that can go wrong with a filter:

1) Installed backwards. Many are directional.

2) Already clogged up with crud, so it's restricted.

3) Doesn't have enough maximum flow rate for the system, but that wouldn't make it idle rough it would starve out at high RPM.

P.S. Which bike do you have? I am not good enough to tell by the pics.

He's right I believe, it really should not affect the idle......

Qdude wrote:

... Now I run no inline filter, allowing the petcock screen to do the job of filtering. I have since had no fuel flow problems....

But likely to eventually suffer carb problems from incoming crud suspended in the ample fuel supply.

if the filter has died already, then I think the tank is the problem, may need to be coated if it can not be cleaned, in no way would I run without a filter on the bike, the screen in the tank dosent filter out the tiny trash that messes up the carbs

Patton wrote:

Qdude wrote:

... Now I run no inline filter, allowing the petcock screen to do the job of filtering. I have since had no fuel flow problems....

But likely to eventually suffer carb problems from incoming crud suspended in the ample fuel supply.

YEP. Most tanks have fine sediment (dirt and rust particles) that will flow down if not stopped by a filter.