Inline fuel filters on GS's - yes or no???

[Chuck78]

Alright so I would like your opinions on this... Do any of you consider it necessary to run an inline fuel filter on a GS?

I have definitely pulled apart some carburetors and found very fine remnants of rust powder in the bottoms of the the bowls. But if you have ever pulled a petcock out of the fuel tank, they had originally a tall plastic frame with a filter mesh in it. This piece also serves as the facilitator of the reserve function on the fuel petcock. It has two different height inlets so that "on" draws from the higher portion, and "reserve" draws from the lowest portion off the bottom of the tank.

A few times I have found these plastic filter/reserve inserts for the petcocks have come loose and fallen out even (if you have no reserve, this us what happened...)


I was weighing thoughts on running an inline fuel filter, versus just relying on the filter screen in the actual petcock. You can get fairly nice brass or bronze porous reusable washable filters for 1/4 inch and 5/16 inch fuel line, 7mm (550 & smaller) or 8mm (750+)


Running one of the straight through type clear plastic filters, having it come out of the petcock and having the hose making a gradual 90 degree bends down to the center of the carbs, I did have one of these plastic type filters break on me once, and have another one that you can see from the air-cooled engine heat, softened and bent into a radius on its own.
Advising a friend on parts to buy for his first motorcycle, a 78 GS550 that I am rebuilding with him, I found some 1/4 inch filters with the brass / bronze element that are actually in a 90-degree configuration, which was nice especially for the 550 (tighter quarters than a 750+ or a twin). I was wishing for a Billet aluminum version of that, but no such luck, only the $10 Emgo/BikeMaster straight Billet aluminum / brass filters.

So that left me weighing thoughts of a Billet aluminum filter that could potentially vibrate and come unthreaded, versus the plastic clear type that could potentially crack under stress, or melt (less likely), vs the more guaranteed leak free method running no filter and just one section of hose with two clamps, and relying on the petcock filter screen only. Like I said, I have definitely found lots of fine rust particles in the bottom of the fuel bowls before.


Opinions on petcock-filter-only vs clear plastic vs billet?




As far as filter element style, I only opted for the brass or bronze porous type reusable washable filters, and don't care to use the filters that are the same type of mesh screen as the petcock screen, and don't care for the paper element type as much as the brass either.

 

[1980GS1000E]

I don't use any inline filter anymore. The one I was using starved the carbs at higher speeds.

 

[Steve]

If the filter is designed for a gravity-fed system, it's OK to use one, if you are more comfortable having one. However, most of the filters available at the corner auto parts store are designed for cars with fuel pumps that will push gas through a relatively restrictive filter. THOSE filters WILL starve a bike engine, especially larger ones.

So far, I have not had enough crud in a fuel thank that required the addition of another fuel filter. I consider myself lucky in that respect.

.

 

[chuck hahn]

Keep your tank full in the off season..or empty if it hasn't had any rust history. This will prevent cud from clogging the filter on the petcock. If youre getting chunkies in the carbs bowls maybe the in tank filter has been compromised. If all is in working order nothing more is needed. Further, since its a gravity feed system an additional filter will slow fuel flow to the carbs and may cause running issues.

 

[Himer]

Yes, you can use additional filter. But IT HAS to be made for communist motorcycle or communist car. Most simplier communist cars used gravity tanks too. In my GSX 400 F Katana I do have additional fuel filter and based on what is in the tank after 34 years I am thankful that somebody did think of that before me. You can go flatout, whatever it just works fine either on track or just road. I also do have some communist motorcycles and believe me you better have additional fuel filter on those regarding fact that communist type did have filtration like our suzukis too. Plus having plastic clear type filter you can actually see if floats do close. Use paper ones, those aren't 2 strokes to use mesh(paper restricts 2 stroke oil).

I use same type of filter as for my communist motorcycles, a paper one. Everything is fine and I have ridden on this wombo combo for 2 years.

 

[sharpy]

My old system was like the pic below and ran fine due to its volume. Was below the tank and above the carbs. Newer system is now hose, copper piping and huge inline glass/metal filter that will take pics off later today.

 

[aclaytonb]

I use use a glass/steel fuel filter from DCC. Seems to flow fine and it sits vertically right above the fuel tee at the carbs.

www.dimecitycycles.com/5-16-inch-retro-glass-chrome-inline-fuel-filter.html

Cheapo plastic ones always leak. This one appeared servicable and I can see the fuel flowing. Used to have a Honda 750 DOHC and if you EVER didnt use a filter, you were removing the carbs for cleaning.

 

[Runeight]

I had to redo the carbs due to rust in the tank. I went with a Pingle inline filter. Can remove screen for service.

 

[Gorminrider]

I think it'd be time to epoxy the tank inside if I was seeing too much rust in the carb bowls...wouldn't inline settling filters without a fuel pump might be prone to extra trouble of airlocks and such on hot days?IE: I don't like to see air in a fuel line......so to clean them you need to "prime" them full and without air too.

On boats, I've used those funky-but-good glass-settling bowl types but I wouldn't do this on a bike unless I wanted a rat or steampunk look...

 

[Guest]

I've tried an inline filter on mine a couple times, yes the gravity flow types as well. Always had the same problem, fuel starvation.

 

[aclaytonb]

Never had that issue. I'm sure it will come up at the most inconvenient time....

 

[Downs]

I really need to kreem my tank as it does ahve a bit of rust build up in there. However, running just the pingel valve's screen in tank has caused no issues.

 

[salty_monk]

The only way I had problem with fuel starvation was when it had enough rusty cr*p in there to block it... I also had one or two soften & bend but never break.

On my Skunk which sat for years I cleaned the tank best as I could but didn't POR15 coat it until years later. For the first year or so I ran a filter & changed it out regularly (the first one after only about 500miles) as a lot of crap was coming out... then it stopped so I stopped using a filter. This was with a brand new petcock with mesh in place.

3-4 years later it started to overflow the bowls - visible cr*p inside the petcock diaphragm caused that. I have the liner now & touch wood nothing like it since..

So I guess it depends on tank condition as to what I'd recommend. It makes it harder to hook things up unless you run something like Sharpy's that's for sure.

 

[mvalenti]

I have the same one (Dime city cycles), no issues. serviceable, and you can see the fuel.

 

[Grimly]

I always run a decent-sized inline filter.
Anyone who's been stranded at the side of the road with blocked carb fuel inlets probably will too.

 

[Fjbj40]

The original filter on the Petcock will allow very small partials into the carbs. It does not seal 100% between the Petcock and the tank thereby partials get into the carbs. The filter is fine enough, but it does allow some partials to go around but not through the filter. I have just done mods to my tank to install a remote cock and the modified factory Petcock filter is actually bonded to the new piece installed in place of the factory petcock so nothing will get past it.

A good flowing filter would be of help in these old tanks.