Topic: Inline fuel filters...yes or no?

[goon 1492]

wow to tired that was a good read, well said.
and having read that i am going to go take mine off and make sure my tank filter is up to par

[hapsh]

Right on TT.  I tried the inline filters before on my 550 and I had a really hard time getting them mounted vertically.  So one was fairly vertical and the other was at a 45 degree angle.  I had several instances where I thought I was running low on gas so I would switch to reserve, then it would go away, only to come back here and there.  I would check my fuel tank and I had plenty of gas.  I would then check the filters and would have to tap on them to get fuel flowing again.  I finally tossed them when one of them snapped when I was adjusting my fuel lines.  It was so easy to break that I was afraid that one could crack while riding and spew gas on my engine. They didn't help any more than the Honda petcock screen anyway.  Ever since I pulled them out the fuel flows much better.  To get really good fuel filtration you need to have the automotive style canister filters and a fuel pump.  You need extra fuel pressure to force fuel through a good paper type filter.

[Gordon]

Lloyd,  I hope by now you have that saved somewhere so you can just cut & paste instead of typing it out every time.

While I agree with just about all your thoughts on in-line filters, I still use them on my bikes.  I've never claimed to always have a good reason for everything I do.

[Hope]

Lloyd,  I hope by now you have that saved somewhere so you can just cut & paste instead of typing it out every time.

While I agree with just about all your thoughts on in-line filters, I still use them on my bikes.  I've never claimed to always have a good reason for everything I do.

well... I currently have tiny little bits of trash in my fuel filter, which I will be changing soon... but that's the reason I still run them.

I agree with you Gordon.  TwoTired's theory makes perfect sense, but I still feel the need to run inline filters.

[Hope]

?

Do inline fuel filters have to mounted vertically?  The inline fuel filter on my lawn mower is not.

[heffay]

?

Do inline fuel filters have to mounted vertically?  The inline fuel filter on my lawn mower is not.

i would have never thought so and still don't but i'm open to listening to the debate.

[TwoTired]

That fuel filter type depicted doesn't care what orientation it's in.  The fuel system it is installed in might, though.  Does the installation trap air and interfere with gravity fuel flow?  When the air bubble it contains, achieves equal back pressure to the head pressure from the tank, the filter stays clean since it stops filtering fuel.  This is good for the filter.

See, when you start changing systems on a bike, you become the engineer and are liable to foresee repercussions of the alteration (or live with the consequences).  It's not just the part selection, it is how it is used, as well.  Can you do this as well as Honda?

Some can.  Some can't.  I just don't see the need, in this regard.  I suppose I'm the minority here.

Anyway, I don't believe you can install that depicted filter on a CB550 without a line loop and keep it from collecting air.  Let's see a pic of the installation, not just the filter.

By the way.  Unless, I can't repair the Honda fuel filters for some reason, I remove all inline filters from bikes I acquire.  If they came with spare tires attached, or twenty extra mirrors appended, I'd remove them, too.  The stock filters have all worked as designed since I started collecting them in 1975.  Why would my bikes be any more "special" than anyone else's?  I know there were a couple times when I was quite low on fuel, that I was very happy to be able to use all the fuel in the tank.  Once, I had less than a quart left in the big 550F tank driving into the gas station.  Had to keep the fuel sloshing over the center hump in the tank while driving.  An air bubble in the line would have left me walking, I expect.

As an aside, I have to ask.  How can you be satisfied filtering your oil with only one filter?  Or, the incoming air only once?   

mercy, TwoTired.

I must admit that I fall into the category of having piece of mind by having the inline filters, but it seems to have struck a nerve with you.

Nah, do what you want.  It's just with a logical understanding of the situation, extra inline filters just seem a silly addition.  I'm just sharing what I know. 
But, perhaps you'd be interested in carburetor turbines to improve fuel economy?  Or, water injectors to save on fuel costs?

Cheers,

[Gordon]

For me it's a matter of convenience.  Almost every bike I've owned did not come with a functioning petcock filter.  In addition, the carbs always need to be removed and cleaned, and the fuel lines replaced. 

I can either locate, order, and wait for delivery of a stock petcock filter replacement, or I can go down the street and buy a couple of in-line filters while I'm picking up the new fuel line.  With a logical understanding of how a gravity fed fuel system works, it's not difficult to install them properly, and I've never had a problem using them on any of the five bikes I've put them on. 

I guess if I ever did have a problem with them or were given a good reason not to use them, then I'd make the extra effort to replace the stock filters, but that hasn't happened yet.     

[City Boy]

Very good expansion of the facts as per my previous post re Honda OEM fuel filtering Two Tired.Honda doubled the pleasure on the twin cams;sock in tank,screen in tap,although the bowl size ironically was drastically reduced .Rock On

[Ichiban 4]

For me it's a matter of convenience.  Almost every bike I've owned did not come with a functioning petcock filter.  In addition, the carbs always need to be removed and cleaned, and the fuel lines replaced. 

I can either locate, order, and wait for delivery of a stock petcock filter replacement, or I can go down the street and buy a couple of in-line filters while I'm picking up the new fuel line.  With a logical understanding of how a gravity fed fuel system works, it's not difficult to install them properly, and I've never had a problem using them on any of the five bikes I've put them on. 

I guess if I ever did have a problem with them or were given a good reason not to use them, then I'd make the extra effort to replace the stock filters, but that hasn't happened yet.    

I'll add my voice for using extra in-line filters.  As elegant as two-tired explanations are usually..I've had absolutely no problems with using them.
 
Some of the gas out of stations nowadays seems pretty dirty (probably always has been the case).  The newer OEM filter screens that go in the tank are made of plastic or nylon now..rather than brass screen.  Not as easy to clean W/O messing up.

Don't know what all the talk is about needing extra room for in-line filters.  If the gas lines are shortened/trimmed to accommodate..everything still is going "down hill".

Bottom line for me though..was that a Honda certified mechanic recommended using extra filters on these old bikes years ago.  So I figured he probably knew a little about what he was saying. Haven't looked back since.

Ichi

[Dave Wyatt]

When I purchased my old Hondamatic in 1995, I removed the petcock while cleaning out the fuel system.  The screen/filter didn't look too healthy, due to deteriation, so I added a small cone shaped filter to the outlet.  I mounted it right after the petcock, so it is easily accessible just under the edge of the tank.  That also gives me good visibilty at any time.  This was easy to do, since the 'matic uses a single fuel line to one carb, and balance lines between the carbs.  I do change the filter once a year as a precaution.

[Gregorymoto]

I vote YES

[goon 1492]

Hey Hope I noticed in the JC whitney catalogue last night that they carry the clear round filters that you talked about, they also carry the cone shaped ones too, and I don't want to sound silly because of my preveous remarks but i am leaving my in line filter on instead of taking it off. my petcock filter isn't in that good of shape and like all the other parts on my bike as they go bad they will be replaced with up to date goods and such. So like i always say call me what you want but DON'T call me late for supper!

[Hope]

Hey Hope I noticed in the JC whitney catalogue last night that they carry the clear round filters that you talked about

They want like $11 to ship

[edbikerii]

I was using an inline plastic-cased, sintered bronze filter also.  I didn't really see any harm in it.  In fact, I'd probably feel more comfortable with one in place now (I don't like cleaning carbs again).  However, one day I was tinkering around with my carbs, and the plastic filter cracked, leaking gas all over the place.  It had become brittle with a couple years of use, and finally just gave up.  So, I just pulled it off.

One benefit of the clear inline filter is that you can see fuel flowing.  That can help troubleshooting sometimes (ok, you could pull off the hose and see if gas flows out, too).

Thank you,

Ed

[loonymoon]

hmm, interesting. I know I've got an inline filter on my bike, I'll have to have a look now to remind myself what type it is  (I think it's a flat square type- oh and I'll keep an eye on it incase it starts causing problems!!

[somesuch]

If adding one filter is good isn't adding, like, 5 extra, even better?  Just think how clean your fuel will be!

Do you care if particles sized 0.002" flow through your carbs and out the exhaust?  Would that harm anything?  Would you even notice it while driving?   Your filter has to stop particles from getting to the smallest orifice the meters fuel.  Usually, that's your slow jet size.  All the stock Honda filters that come with the bike block particles that can harm carbs.

Adding extra filters, also adds extra maintenance. Even if your added filter blocks finer particles than the Honda supplied one, where do they go?   They stay in the filter, which you have to clean or replace periodically or it gradually and incrementally reduces fuel flow capability.  When do you find out that this has occurred?  On the freeway when you engine overheats and holes a piston due to progressive and repeated fuel starvation?

The early Honda petcock filters have a sediment bowl, that once a year, you remove, clean and reinstall.  The bowl splash flushes the screen to keep it clear and flowing (unless your tank is hopelessly rusted).  The screen prevents particles that won't fit through carb orifices from reaching the carbs.

The later Hondas have an in-tank filter that blocks even finer particles than the earlier type.  There is no sediment bowl, the sediment is held in the tank.  The sloshing of the fuel in the tank constantly clears the mesh so proper flow in maintained (again, unless your tank is hopelessly rusted).   It still won't allow any particles to reach the carbs that can block metering orifices.

If your stock Honda filter is installed properly and functioning as delivered, you don't need another (or several more) filters on your bike.

As mentioned earlier, the fuel feed from tank to carbs is done with gravity.  Any plumber worth listening to, will tell you that such systems need a constant grade reduction to flow properly.  Loops and dips in the line, trap fuel or air.  When the tank level gets low enough to the drain, either the bottom of the tank on reserve, or the stand pipe height, the head pressure falls very low, such that an air bubble trying to rise, can block fuel flow, or worse reduce fuel flow, leaning the fuel mixture.  Honda doesn't provide much room in many of their bikes to insert a useless filter, without adding a fuel line loop.

That's the science of it.  However, if adding filters is a religion for you, or a habit like locking your door three times, you'll gain peace of mind by adding an extra fuel filter...or three.  It is something fairly easy to do to make operators feel they've done something nice for their machine... like the best oil they can find. 

Cheers,

Just stumbled on this thread looking for a rubber replacement washer for a petcock and thought it would be a service to some to bring it to the top.....Just last Sunday saw someone on a side of the road with the air bubble/reserve predicament. I pull those cracking/bubble trapping filters of all the CB750s that I can On other bikes, like the BMW airheads, there is a nice natural place to mount those filters with plenty of space....but not on most multi cyl. Hondas...

[AbbyRider]

The inline filters are invaluable for those of us with rust issues in the tank. It's been almost a year since I restored my bike, including the inside of the tank. But I'm still getting tiny pieces of the rust caught in the filter, as they're smaller than the petcock screen (i dont have a filter on the petcock tube). Haven't had the jets clog though.

[70CB750]

I don't run them, I am quite happy with the petcock and simple two fuel hoses.    Particles are small enough not to bother the carburetor, fuel injection would be a different story of course.

[dhall57]

Don't run them on either bike. The PO of my KO had some type of inline filter rigged up. One of the things that was wrong with the bike when I got it was a leaking petcock so I rebuild it and did away with the inline filter and put in a new petcock screen. I think the way Mr Honda designed the fuel systems is more than adequate, so why run a inline filter. But to each his own If it gives you piece of mind to run one on your sohc4 by all means do it
I just don't think I need to on my bikes.

[Deltarider]

Had them and they caused nothing but trouble, so I abandoned them. I have the original white nylon filter above the petcock that protrudes into the tank. Worked fine the last 35 years.

[grcamna2]

Very good expansion of the facts as per my previous post re Honda OEM fuel filtering Two Tired.Honda doubled the pleasure on the twin cams;sock in tank,screen in tap,although the bowl size ironically was drastically reduced .Rock On

I see the logic in cleaning you're tank the best possible way so your feeding you're carbs the cleanest fuel possible and then the understanding of an O.E.petcock w/sediment bowl & fine filter screen installed..it makes sense.
 I'm on the hunt for an NOS fuel petcock & possibly Evaporust to get as much sediment out of my tank as I can...