Topic: 1975 CB550 In tank Filter-PLEASE HELP

[fletcha221]

Guys,

Rebuilding a a 75 cb550, I pulled the petcock off the tank, as I thought, the plastic "spine" of the in stank filter was broken. Anyhow...I understand the 74-75 are the only years designed like this. My question is:

Where can I buy a filter?? All i can find are the NOS ones on ebay for like 70 bucks. Any help would be much appreciated!!!!

[fletcha221]

Any help Oldtimers??

[steam-powered man]

i use a right-angle, in-line filter.  i usually keep a few on-hand as I can get ham-fisted some days and they crack easy.  make sure no "droops" or air pockets can occur.  on my '72cb750, i used one for each line.     

[fletcha221]

I thought about the inline one. However, the cb550 has 2 fuel feeds off the petcock. Do you think 2 will be ok, or will it restrict the flow too much?

[Gordon]

Let's go ahead and get this out of the way:

An in-line filter isn't a band-aid for a broken or missing petcock filter.  It's an inexpensive, easy to install, and viable alternative to replacing the stock filter.  Simple as that.  It does the exact same job, and does it just as well, and as long as it's installed properly (as anything on your bike should be) it will cause no problems. 

I don't think it is exactly the same.  The inlines collect debris and hold it.  If it collects enough debris, the filter becomes restrictive. The intank type is where the fuel is, and the sloshing clears debris away from the filter, allowing full flow.  Any debris present, stays in the tank where you can flush the entire tank if your tank is manufacturing debris, or you are constantly putting more debris in the tank.  In this regard

An inline filter must be added to routine maintenance (replacement) as its action of filtering and trapping particles will eventually restrict fuel flow, and this WILL cause problems.  The maintenance schedule must created or specified to replace the inline filter at an interval greater than the debris introduction into the tank.  Anyone care to guess what the introduction rate is?
The filter's particle size specification need only be slightly smaller than the smallest orifice in the carbs. This is most often the Slow/Pilot/Idle jet.  Particles smaller than the orifice pass right on through the carbs without collection or stoppage.
In this regard, you are adding to your maintenance chores if your chosen filter is trapping too small of a particle size, and preventing this self cleaning action.

Finally, have any of you filter clean freaks put filters on your carb vents?  These are normally ported directly to the dirty, dusty, filthy atmosphere, in the same way the fuel tank vent without any filtering whatsoever.  If you are obsessive about dirty fuel entering you carbs, why aren't you the least bit concerned about these other avenues of direct dirt injection?

In the barnstorming days.  Pilots would carry a chamois with them.  This chamois was used as a filter for fuel being added to the fuel tanks.  (fuel was often brought to them in 5 gallon cans from local gas stations.)
This helped keep the entire fuel system cleaner, and help prevent engine stoppages from clogged inline fuel filters.

Do you inline filter advocates pre-filter the gas getting to your tank as well?

I guess I really don't care if you want to install inline on your fuel system.  (I haven't needed them on any bike I've owner since 1967. And, have removed them from machines that I have collected.)  But, it is another item to put on the checklist when the engine stops performing, which may or may not add to the repair time needed to get you going again.  If you are a competent enough mechanic, this is of little issue.  It's the inexperienced that I try to guide.  In-lines are not a panacea or a substitute for a clean tank and filter.  And not all newbies need to be advised that an inline filter is essential for proper operation of these old machines.  It quite simply is just another add on of dubious value.

There WAS one time where I wished I'd used an in-line.  That was on my CX500.  The PO had removed the in-tank filter, and I cleaned the carbs twice before discovering there was NO fuel filter at all.    My bad.  At least there were only two carbs.

That's just the one I happened to choose.  There are many others exactly like it if you feel like doing a quick search to find and read them. 


Now that that's taken care of..

In-line filters won't restrict the fuel flow unless they're either dirty/clogged or installed incorrectly.  You can run 90 deg angle filters as has been mentioned.  Straight filters should fit as well (that's what I have on my 550), but some have had problems getting them to fit without kinking the fuel lines. 

[Frostyboy]

Is this what you are looking for?

http://forums.sohc4.net/index.php?topic=72971.msg810384#msg810384

[Gordon]

23 bucks is a lot less than 70 for sure!

[fletcha221]

Yep! Thats exactly it.

I did some endless searching on ebay and found this one.....the picture is terrible, but i THINK, it's the correct one. If not, looks like I'll be ordering from overseas.