Topic: Filter Question

[Vintageguy]

Had a stuck float the other day on my 1978 cb750F. Got it cleared, but my question is; Should I put in an in-line filter? Recently drained the tank dry. Perhaps I disturbed a little piece of crap in there. Dunno. Will a fuel filter cut down on necessary fuel volume? Thank for any/all responses.

[newday777]

What does the inside of the tank look like?

[Vintageguy]

Good. Clean. Not cruddy at all.

[newday777]

Pictures help.
Has it lined?

[newday777]

How did you drain it? The 78 F tank has a long tube strainer inside the petcock, did you pull that out and inspect it for damage/holes?

[Vintageguy]

Did not pull petcock out.

[Tim2005]

There is no harm in having an inline filter, I always run them. If it stops 1 tiny piece of crud from blocking a pilot jet then it has saved a load of work

[newday777]

The problem comes with filters that are not positioned so there is constant down hill flow through the lines to the carb inlets from the petcock. Any uphill tubing will hinder the flow of gas.
I'm the camp of clean the tank out fully and insprct the internal petcock strainer very first sign of problems.

[newday777]

This is how a tank should look.
Any slight sign of surface rust is a problem and needs a thorough tank derusting procedure.

[BenelliSEI]

There is no harm in having an inline filter, I always run them. If it stops 1 tiny piece of crud from blocking a pilot jet then it has saved a load of work

+1 to the above. Lots of people will blame them for all kinds of evil. Not to get started, but I disagree. Use new Honda fuel line and make sure it all runs down hill with gentle (no kinks) bends and they work fine.

[willbird]

Had a stuck float the other day on my 1978 cb750F. Got it cleared, but my question is; Should I put in an in-line filter? Recently drained the tank dry. Perhaps I disturbed a little piece of crap in there. Dunno. Will a fuel filter cut down on necessary fuel volume? Thank for any/all responses.

Does the petcock have a screen ?? The OEM petcock screen is really fine, maybe purpose designed to filter most things that can cause an issue ??

Bll

[grcamna2]

The problem comes with filters that are not positioned so there is constant down hill flow through the lines to the carb inlets from the petcock. Any uphill tubing will hinder the flow of gas.
I'm the camp of clean the tank out fully and insprct the internal petcock strainer very first sign of problems.

Most certainly agree. 

[willbird]

The problem comes with filters that are not positioned so there is constant down hill flow through the lines to the carb inlets from the petcock. Any uphill tubing will hinder the flow of gas.
I'm the camp of clean the tank out fully and insprct the internal petcock strainer very first sign of problems.

Most certainly agree. 

it can be worth it to unhook the fuel lines and hook a drain line to the petcock and switch it to "reserve" if it has one, the "stuff" lives down in the bottom on the tank when you run on thje standpipe, anmd when you flip to reserve that stuff gets dumped into the sediment bowl. Back in the day all gas except Sohio (with ICEGARD, you go or Sohio pays your tow) the water would separate out and wait in the very bottom of the  tank until the poor rider had to flip to "reserve".

Bill

[grcamna2]

The problem comes with filters that are not positioned so there is constant down hill flow through the lines to the carb inlets from the petcock. Any uphill tubing will hinder the flow of gas.
I'm the camp of clean the tank out fully and insprct the internal petcock strainer very first sign of problems.

Most certainly agree. 

it can be worth it to unhook the fuel lines and hook a drain line to the petcock and switch it to "reserve" if it has one, the "stuff" lives down in the bottom on the tank when you run on thje standpipe, anmd when you flip to reserve that stuff gets dumped into the sediment bowl. Back in the day all gas except Sohio (with ICEGARD, you go or Sohio pays your tow) the water would separate out and wait in the very bottom of the  tank until the poor rider had to flip to "reserve".

Bill

Good advice 

[rotortiller]

There is no harm in having an inline filter, I always run them. If it stops 1 tiny piece of crud from blocking a pilot jet then it has saved a load of work

I have external filters on two CB750s, 4 Kawasaki H2s and one H1 with absolutely no issues. I like the fact that no debris can get under the float valve seats and that I can see the filter media easily. Like with anything a filter installation can be buggered up, some guys would screw up the lord's prayer, that is provided they actually knew how it went lol.

A wise man once said:

when you flip to reserve that stuff gets dumped into the sediment bowl.

Some petcocks do not have a sediment bowl making matters worse.

[madmtnmotors]

Originally there will be a filter screen inside the fuel tank surrounding the reserve tube. The filter screen typically remains inside the tank when the petcock is removed. Look up inside the bung after removing the petcock and/or shine a flashlight down inside the tank (NOT a lighter!) and look for the filter screen. If the original filter is still in place, which every late model tank I've ever laid hands on has always been the case, they will require some persuasion to remove. This would be a good time to replace the petcock seal. The only problem is the seal is not available separately, but it does come with the new filter screen, except the new filter screen (16952-388-015) is NLA from Honda. An aftermarket petcock will come with a new filer screen and seal so you could get the cheap aftermarket petcock ($20) and harvest the seal. The aftermarket filter screens that I've seen are questionable, so you might consider an inline filter after removing the old in-tank filter screen.

[seanbarney41]

78F does not have a sediment bowl.  It should have a pickup screen in the tank that covers both the "on" and "reserve" settings.  The screen is extremely fine.  Anything that gets through is gonna get through all the cheesy plastic fuel filters you can add, so  check it for rips and damage and you are good.

I see Mmm. has added further detailed info to what I was about to post and I would tend to agree.

[willbird]

78F does not have a sediment bowl.  It should have a pickup screen in the tank that covers both the "on" and "reserve" settings.  The screen is extremely fine.  Anything that gets through is gonna get through all the cheesy plastic fuel filters you can add, so  check it for rips and damage and you are good.

I see Mmm. has added further detailed info to what I was about to post and I would tend to agree.

I did google some images, that is interesting, it would avoid the potential trash dump from flipping an earlier one to reserve for sure.

[Dime]

I am taking notes for my 78 750k tank. I will be tacking it later this winter. Great post.

[kerryb]

I got this bike with cheap pods and a little rust in the tank.  See the filter in the worst possible position because that’s where it would fit.  Now has a proper stock air box so it runs well.  I kept this filter on since I put it on 3 years ago even with a $20 petcock from “flypig” on ebay.  I figured it would be on there until it was a problem…no problems yet.  Possibly, I’m the fluke, with good results from the the wrong application.

[MauiK3]

Filters are fine, I think, until they are not and then there will be fuel starvation causing lean running.

[kerryb]

So true.

[rotortiller]

I did mine the same as kerryb on a CB750 but my near identical filter sits between 1 and 2 carbs out of sight unless a mirror is used or the tank is off. It was a tedious fitment and I do have a horizontal loop with a slight incline. Works good, lasts a long, long time and the engine just like kerryb's has access to every drop of fuel, even in traffic during the heat of summer. It is possible that people with flow issues have a problem with marginal filter media, filter design or tank venting. I have never had a lack of flow with inline bike filters unless they were clogged with 5hit. First thing I do after the install is turn on the petcock and watch the fuel enter the filter. Even with some air in the filter canister it still flows fine. If the petcock or finger screen was clogging up but left in place with the addition of the inline filter, it will still plug and block fuel flow.

[BenelliSEI]

Filters are fine, I think, until they are not and then there will be fuel starvation causing lean running.

True. The same could be said for the bowl screen or “straw filter” on all our Hondas. Some maintenance required.

[MauiK3]

I've never been a fan of the little in line filters, not much room down there to get a nice angle and keep flow going without restriction or air locking. I'm sure there are many examples that seen to work but I steer clear of them.