Topic: Fuel filters - the good and the bad?

[andy750]

Hi all,
Ive used the glass fuel filter types before with much success but they were the big ones (sat outside the carbs) and Im looking for something a little more compact. I tried some clear plastic ones but one (I have 2 fuel lines) cracked and leaked fuel putting me off these. Does anyone have positive feedback on fuel filters - ones that can be placed conveniently, and wont starve the carbs of fuel and stupid things like that.

thanks for any input and as usual photos always help 
Andy

[csendker]

I've had the little plastic ones since I bought my bike 2 years ago.  You can see one in the pic, the other is buried behind the carbs.

[Gordon]

I've never had any problem with filters like the one shown above.  Just try to keep them in a fairly straight section of the line so the ends aren't stressed, and they should be fine.

[TwoTired]

What's wrong with the one in the tank or petcock?

Cheers,

[clarkjh]

What's wrong with the one in the tank or petcock?

Cheers,

PO lost/pulled off the one on mine, there for no in tank filter.  I need to rebuild my petcock, the screen is shot.

James

[mrbreeze]

That sock (as I call it) filter in the tank is kind of a #$%* to service but it does keep the crap out of the petcock that will ruin it over time. The inlines keep the secondary crap out of your carbs. I would like to be able to keep the sock over the petcock (primary filter) and run an in line that is big enough to let fuel flow (secondary) but mount it in a spot that doesn't bind it up or make it a pain to service. Unfortunately,Honda didn't give us much to work with. Any ideas are always welcome with me. I have had problems taking the petcock out and getting a good seal afterwards....thats why I don't like to service the sock filter in the tank.

[grumburg]

My screen is shot too. Hid the cone filters. Replace them every couple years, even though they  are clean.

[TwoTired]

The in-lines keep the secondary crap out of your carbs.

What secondary crap?  The in tank filter is so fine a mesh, that any particles smaller than the mesh opening will flow right through any orifice in the carbs.
In fact, I wonder why you'd need any mesh or filter material that is any finer than the smallest jet orifice.

I've no problem with a fuel filter requirement.

I'm not understanding the technical advantages of an external filter over the one Honda provided.  Are replacements so hard to obtain?  Have I just been lucky with my purchases?

Cheers,

[kettlesd]

I with Two-tired. The OEM screen thats inside the tank is a pretty damn fine mesh. Ive had a tank without a mesh "sock" and i fitted an inline. but the run from the tank to the carbs made such an angle at the filter that fuel restriction was a definite concern. I bought a "sock" and found it is easy to clean down the road too. Remove from the tank and wash it gently with clean gasoline followed by some carb cleaner.

[Roach Carver]

correct me if i am wrong but didnt the early tanks have no filter in the tank, just a pick up tube?

[BobbyR]

correct me if i am wrong but didnt the early tanks have no filter in the tank, just a pick up tube?

There is a small screen in there to filter out heavy stuff. I use a filter on my 78 750K. This year I have a filter with a 90 degree bend. I have not fit it yet, but I expect it will go straight up between the carbs and then attach to the petcock.

[csendker]

Dumb question; can you still buy the OEM sock?

Item #06: STRAINER SET 16952-341-671  Qty: 001 $21.71

It's listed on the parts fiche, but does anyone know if it is still available (although I suppose I could call them tomorrow...)?  Dumping the in-lines would help clean things up around the carb.

[mrbreeze]

Man....thats what I remember last time I priced them...around $20. Pretty steep for a fuel filter although it can be cleaned and reused. I'm not sure about availability but to get in there and service it , I want a new rubber gasket inside the petcock.

[techy5025]

Two Tired,

I suspect the problem may not be the jets clogging but rather particles lodging in
the float valve and causing the carb to overflow.  Happened to me several times
and I never figured out what was caught in there. Usually, removing the bowl and
jiggling the float gets rid of it.

Having said that, I have never used inline filters and I don't think the tank has any
filter....just the strainer in the petcock.  The space is so tight around the carbs that
adding two filters would make for some interesting line routing...it would seem. 

Jim

[Zane]

Dumb question; can you still buy the OEM sock?

Item #06: STRAINER SET 16952-341-671  Qty: 001 $21.71

It's listed on the parts fiche, but does anyone know if it is still available (although I suppose I could call them tomorrow...)?  Dumping the in-lines would help clean things up around the carb.

IMHO any questions regarding parts availability for a motorcycle over thirty years old just can't be a "dumb question" - by definition.

I bought two of the above part from my local dealer (Toronto) a few months back.  When the parts guy looked it up on the computer he said there were two in Vancouver, so I'd have to wait a couple of weeks.  I guess they're just getting harder to get (which is why I bought two).  I thought the price was a bit steep, but when I received them I could see they are, indeed, an assembly or "set".  You get the "sock" with a couple of (relatively unique) washers (including the flat sided rubber one with the two holes in it) and a nice shiney plumbing nut.  (The new nut motivated me to really clean up the valve handle and housing, just so they didn't look so grimey in comparison.)  (There must be a name for that little rubber specialty washer - I just don't know what it is.)

When I pulled the old sock out of my tank, it was intact but almost solid with rust.  I cleaned it out well, and kept it for a backup.  As far as the inline filter on my bike goes - I'm wanting to fall over to TT's approach to the issue.  (Last winter I had the inside stripped and relined - it's very clean now.)  My (albeit limited) sense of it is to get rid of the in-line filter.  I don't really trust it, I'm not sure if it's a finer fliter than the sock, and there's so little room on the line.  If I could find that proper gas line I bought last year for my bike, I'd get rid of the filter tonight.  But I misplaced it, so I'll wait.    

I wonder if it's possible to find out to what micron level that Honda "sock" filters?  There's certainly little advantage in putting anything down the line which has a fatter rating.

Cheers,

Bill

[techy5025]

The problem with fuel hose is that the type that has the right inside diameter...I think
everyone uses quarter inch...has too big an outside diameter and won't fit through the
routing holes in the carb backing plate. Most hoses have too high a pressure rating.

Probably the best type to use is auto vacuum hose if you want the black stuff.

Jim

[chung]

Item #06: STRAINER SET 16952-341-671  Qty: 001 $21.71

Is that for the sock, the screen or the whole rebuild kit? I have bought dozens of the screens but seems like 5-10 bucks sounds par?

As for external filters:
I think it all good if you like it but TT is correct. If it's all in good nick then it's all in good nick....... right?

I have removed the sock and screen and use the beer can size filter to get the residule crap out of the tank. After a few hundred cleaning sessions, I replace the stock items and no more problems. Catch it on empty and clean the screen. By the end of riding season, all is good.

As for those little pointy things, took a fat 10mph off my top speed on a CB450. Drove me nuts. The 450 has smallish float bowls and I was running outta fuel. The fuel system was like a wine glass, clean as it can get but I was hungup on this "filter thing" They flowed just enough to keep it going. If it had been a hot motor, I would have holed a piston or two!!!!!!!

Just because you can blow through it doesn't mean that it is still OK. Cost of riding, check and/or change fuel filters every couple months. We're only talking a couple bucks dammmmmmmmmmm.

[medic09]

The problem with fuel hose is that the type that has the right inside diameter...I think
everyone uses quarter inch...has too big an outside diameter and won't fit through the
routing holes in the carb backing plate. Most hoses have too high a pressure rating.

Probably the best type to use is auto vacuum hose if you want the black stuff.

Jim

I wouldn't suggest vacuum line for fuel.  It's not made to carry fuel, and likely will not hold up over time.  I went nuts looking for 5.5 mm fuel line in the auto parts stores and specialty places locally.  Finally got the Honda dealer to order some Honda line in the size I need.  The last bit of line lasted more than 20 years, so I figured over time the price will be worth it.

[Raul CB750K1]

My two cents in this subject:

- I bought a new mesh for the petcock when I bought it- available from Honda
- I installed inline filters when I had an issue with leaking carbs
- inline filters caused an issue with fuel flow, because of air trapped and also because of the lines routing
- when I removed the filters I cleaned the sediment bowl as I was at it - I couldn't believe how much crap was trapped in there, in just a matter of a year or so.


So, I run only the petcock filter, switch the petcock to off whenever I park my bike and have full peace of mind.

[andy750]

Thank for all the replys and opinions on external fuel filters - always good to hear others experiences. Something to consider - a replacement sock (internal filter) is $20 from Honda whereas a new petcock (presumably with inline filter) is available from DSS for ~$40.

thanks all,
Andy

[chung]

Ditto on the lines. California gas will melt a lot of rubber w/in a day it swells up and turns to goo.

While you are getting the petcock, check on the line. Most shops carry aftermarket line. Can't remember who makes it but it has a small OD and comes in several colors.

[mrbreeze]

So you are saying the old black rubber fuel line that came on the bike originally won't hold up to California gas? When I got fuel line at the dealership here,they gave me the clear plastic line that does have the fatter OD. So now I'm wondering if I can still get the original rubber hose. As far as the "petcock screen".....I think that was only on the early models with the petcock on the right side of the tank (screen in chamber that unscrews from bottom of petcock). When the petcock moved to the left side of tank (74-75), the petcock "bowl" was discontinued and they went to the sock inside the tank covering the fuel pickup tubes. I also wouldn't use regular vacuum hose. I don't think its up for the job.

[BobbyR]

So you are saying the old black rubber fuel line that came on the bike originally won't hold up to California gas? When I got fuel line at the dealership here,they gave me the clear plastic line that does have the fatter OD. So now I'm wondering if I can still get the original rubber hose. As far as the "petcock screen".....I think that was only on the early models with the petcock on the right side of the tank (screen in chamber that unscrews from bottom of petcock). When the petcock moved to the left side of tank (74-75), the petcock "bowl" was discontinued and they went to the sock inside the tank covering the fuel pickup tubes. I also wouldn't use regular vacuum hose. I don't think its up for the job.

I have taken to using a urethane hose that does not need to be clamped, in fact once on it needs to be cut off. It is used for go carts. f

[TwoTired]

The warning here is for black hose happily sold to you by ignorant auto parts salesmen and is usually marked as vacuum hose.  This hose is not rated to withstand the chemicals found in gasoline, and deteriorates quickly.  It is, however, the perfect size for out SOHC4 fuel fittings: 7/32 which is as close to 5.5mm as you need to get.
There are many formulations of rubber that are tinted black.  But, just becasue a hose is black does not stipulate a specific formulation.

The only place I've been able to find 5.5mm hose is the Honda dealer.  It had a bulk number and I bought a length of it in bag: 5 or 10 ft, I think.  It is black.  Don't remember the price, though.  California gas doesn't seem to accelerate the Honda hose breakdown any more than simple age does.  This stuff probably should be replaced every 20 years or so, as that's when the ends where it is stretched over the nipples start to split.

I have yet to find clear tubing that won't harden within 5 years.  But, I gave up looking when I bought the bulk hose from Honda about 15 years ago.

Cheers,

[mrbreeze]

The warning here is for black hose happily sold to you by ignorant auto parts salesmen and is usually marked as vacuum hose.  This hose is not rated to withstand the chemicals found in gasoline, and deteriorates quickly.  It is, however, the perfect size for out SOHC4 fuel fittings: 7/32 which is as close to 5.5mm as you need to get.
There are many formulations of rubber that are tinted black.  But, just becasue a hose is black does not stipulate a specific formulation.

The only place I've been able to find 5.5mm hose is the Honda dealer.  It had a bulk number and I bought a length of it in bag: 5 or 10 ft, I think.  It is black.  Don't remember the price, though.  California gas doesn't seem to accelerate the Honda hose breakdown any more than simple age does.  This stuff probably should be replaced every 20 years or so, as that's when the ends where it is stretched over the nipples start to split.

I have yet to find clear tubing that won't harden within 5 years.  But, I gave up looking when I bought the bulk hose from Honda about 15 years ago.

Cheers,

Good info Lloyd......I didn't even ask if they still had the original fuel line at Modesto Honda....I just took the clear plastic that they gave me. Now 2 (maybe 3) years later, that stuff isn't as clear or flexable as before. I haven't tried yet but not sure if it fits in the holes through the carb rack that we were talking about earlier. I know that the stock black hose has a smaller OD though. I will check back with Honda and see if I can get me a length of it.