Topic: Fuel Filter--Which one?

[dansvs]

My 82 CB650SC will repeatedly overflow from the carbs(not always same one) and also keeps clogging the pilot jets(more often #3). I find some very fine sediment in the float bowls which seems to be rust even though I can't see it in the tank. I would like to put in an inline fuel filter. Any suggestions?

[bozo4onion]

I feel your pain. I'm looking at my 3rd rebuild this spring. Some here say "no filters, the tank screen is enough" but every few months I get overflow from clogged needle valve. My tank looks great too. I'm getting really tired and broke (have to replace stuff while I'm already in there y'know) and am considering filters. I've heard since the supply is only gravity feed the filters cause delivery issues. I'll lurk your thread, thanks.

[d3buttz]

this may just be my experience, but avoid those crappy plastic in-line ones(the small clear tapered product that all the shops carry at the counter). with every one i ever used no matter how far i routed away from the motor it still melted from the heat and wound up closing itself up or deforming to the point where it bent and closed the line.

[OldSchool_IsCool]

You definitely want to check your in-tank filter.  Replace it if it has any holes or tears.  Avoid the in-line filters if you can, they can trap air and restrict fuel flow.  If you MUST add an in-line filter, mount it vertically to reduce the possibility of an air bubble.  Your fuel line should ALWAYS flow down hill.  If it has a high spot anywhere, it too can cause an air bubble.

[andy750]

The fuel filter debate has occurred before and you can search and find lots of info about the pros/cons if interested -key in "fuel filter" and you`ll get a LOT of info...

My experience with inline filters has been good. I used to have the big 1/4 glass fuel filters from the auto store on my CB750K2. the would sit outside the carbs on the right hand side  - you could look down and see fuel coming through...I loved them! No air or acceleration issues. They didnt really filter very good though as I still found plenty of sand in my carbs after my Mexico trip.

I then tried the plastic fuel filters from places like Z1 or Bikebandit. These have a finer filter and you can install one to run along the top of your airbox to carbs 1/2. One cracked and leaked. Next one has been better but Im going to remove it. It may be the routing but it will get some air sometimes and I it may (not sure yet) affect acceleration.

No real easy answer but why not try it for yourself and see what affects it has.

good luck
Andy

[bozo4onion]

Looks like I'm rebuilding my tank along with the carbs this spring. Hope the screens are still available.

[TwoTired]

My 82 CB650SC will repeatedly overflow from the carbs(not always same one) and also keeps clogging the pilot jets(more often #3). I find some very fine sediment in the float bowls which seems to be rust even though I can't see it in the tank. I would like to put in an inline fuel filter. Any suggestions?

Fix the in-tank filter.
Be wary of where you buy fuel.
Try to keep the tank full, particularly if the bike sits for long durations.
Run the bike more often and farther distance.

Fuel is a pretty good solvent.  Steady constant flow, cleans the entire fuel system while it flows, and the vibration helps with its agitation effects.  Fine sediment will flow right through the carbs if the bits are smaller than the pilot jet size.  But, if fine sediment is allowed to sit and collect, they bind together to form larger particles that can block pilot jets and keep the float valves from fully closing.

Cheers,

[steam-powered man]

my suggestion would be to use a clear in-line filter, mounted vertically, just below the petcock.  you can watch fuel flow, no air bubbles, no heat.     

[MickeyX]

on our '80 cb650, we just don't have enough room to fit a filter and keep it upright so it would get an air bubble and restrict flow. we put in a new in tank filter and a new fuel line with a unicoil to keep it from kinking on the short 90 deg turn down to the carbs. no more problems. oh, we put a different tank on it eventually because the old one was lined and it kept clogging the hell out of everything. the liner looked good but it still clogged the carbs and we saw lots of grit and rust from it.

good luck. 

[tlbranth]

In the 70's I used the plastic inline filters with no problem. So when I restored the bike, I put some new ones on - had a hard time finding them but finally got some at a tractor shop. I'd already de-rusted my tank per instructions found on this site but I kept having fuel problems. Started out OK on normal petcock setting but bad on reserve. Then bad on both. I finally traced the problem to the filters - and it had nothing to do with an air bubble. I pulled the hoses and dropped the line/filter straight down  and.... nothing. Blew through the filter and fuel came out. I think they were maybe gumming up. But whatever they were doing wasn't working for me so I took them out and now the bike runs fine. Think I'll go with just the mesh in the petcock from now on.   

[Duke McDukiedook]

How about cleaning and lining your tank?
Sounds like you will just keep clogging up any type of filter you put on if you don't address the root problem, a rusty tank.

Then you can 86 the inline filters entirely. 

[dansvs]

Thanks everyone, I knew of the strainer at the bowl but not of the one up in the tank. Plan on pulling both and see what can be done.