Topic: In Line Fuel Filter

[kmenzel]

I have searched for in line fuel filters and after a carb rebuild i want to put them on.  For a cb750, what has been the best way or place to put them.  Did you install 1 or 2 and did you add a t.

thanks

[Bob Wessner]

Personally, I installed two, one on each line. I positioned them so I could see them easily from the right side. I may move them so they are more behind the carbs rather than the to the side when I install some new fuel line.

[kmenzel]

Did your route the fuel lines through the back of the carb plate like they were orginally

[Bob Wessner]

[Did your route the fuel lines through the back of the carb plate like they were originally/quote]

I may not be interpreting your reference to through correctly, but both of my lines are coming off the petcock and wrapping around the outside of the #4 carb and then across behind the entire rack of carbs.

[Jonesy]

Not sure how the K0 was setup, but the later carb stay plates had two holes in them between the #3 and #4 carbs. The fuel lines were routed through them, likely to keep the lines from getting tangled up the the throttle assembly. The only issue is that with the thicker aftermarket rubber fuel line commonly available, the tight bends required to route the fuel lines correctly (read: as in stock fashion) usually causes the lines to kink and restrict the flow of fuel. With the OEM line or thinwall clear fuel line it works OK. I've seen some people just aim the T's between the carbs downwards and make a simple loop between the T's and the petcock. This way it's very easy to find room for an in-line filter and they hang down under the airbox in plain sight.

[kmenzel]

That seems the best way to do it is to route them down below the airbox up to the fuel tank.  I woud imagine to not restrict fuel flow a person should use 2 inline filters.

[Bob Wessner]

The only issue is that with the thicker aftermarket rubber fuel line commonly available, the tight bends required to route the fuel lines correctly (read: as in stock fashion) usually causes the lines to kink and restrict the flow of fuel.

Yup, that's exactly what happens. Recently acquired some correct 5.5mm line, maybe I'll look into rerouting them, but have had no problems thus far.

[fhoffman]

I put 2 in-line fuel filters on my bike, they are visible from the left side.  One seems on occasion to cause a bubble to form in the line blocking the flow of fuel.  It's inconvienient, but I don't want to do without the filters and just a quick line bleed and the problem is solved. 

[dusterdude]

Not sure how the K0 was setup, but the later carb stay plates had two holes in them between the #3 and #4 carbs. The fuel lines were routed through them, likely to keep the lines from getting tangled up the the throttle assembly. The only issue is that with the thicker aftermarket rubber fuel line commonly available, the tight bends required to route the fuel lines correctly (read: as in stock fashion) usually causes the lines to kink and restrict the flow of fuel. With the OEM line or thinwall clear fuel line it works OK. I've seen some people just aim the T's between the carbs downwards and make a simple loop between the T's and the petcock. This way it's very easy to find room for an in-line filter and they hang down under the airbox in plain sight.

well ill be...i wondered what them 2 holes were for.

[Bob Wessner]

Glad this thread started also. Since I've owned the bike, the fuel lines were always routed around the outside of the #4 carb. When I got it out it's 22 year hibernation, I cleaned the carbs and installed new, after-market fuel lines. Looked briefly at trying to route them out of sight, but it was too thick and the fuel filters I installed presented a problem. Since looking nice was not my highest priority at the time, I just continued to route them the same way. Have some new, correct fuel line and I'll try correct routing, though I may have to forgo the filters or get some different ones.

[Gordon]

Bob, I got some really small in-line filter from Cycle-re-cycle, I think.  They're just the right size as to not affect the routing of the fuel lines, you just cut out an equal length and they fit right in.

[kmenzel]

Here is a couple of pictures of stock routing i beleive

[Bob Wessner]

Thanks, will check them out. I know they come in different lengths and shapes, some even have a right-angle outlet. I just didn't give it much thought back at the time, it was more "can I get this thing running?"  

[Gordon]

Thanks, will check them out. I know they come in different lengths and shapes, some even have a right-angle outlet. I just didn't give it much thought back at the time, it was more "can I get this thing running?" 

I know what you mean, but that's good because there's always got to be something you can improve on or tweak just a little bit!   The filter I ended up with are only slightly larger in diameter than the fuel line and about 1.5" long.  I have the lines routed between #3 and #4 carbs, and you can only see them if you squat down and look for them. 

[Bob Wessner]

Here is a couple of pictures of stock routing i believe

I believe I'll still try rerouting them out of sight, but the K0 carb stay plate is different, and quite basic. There are no separate pass-thru holes at all, save for the carb throats and the screws that attach them to the plate. The fuel line will either have to pass between carbs on top or underneath the plate, but I know they can be routed out of sight somehow as I've seen some pics. I'm thinking over the top but between the individual cables.

After taking another look at the drawing, I noticed two crescent shaped cut-outs on the lower edge of the plate that would line up with the fuel "T"s. These may be to provide some relief for an upward turn of the fuel lines. Maybe I'll try that first. 

[Objectionableone]

I'm stuggling with the same issue right now. I don't really like the present set up, I'm not even sure it will flow all that well.

[Bob Wessner]

Great minds think alike.  That's exactly how mine, with filters, is routed today. I have no flow issues, but will be trying to reroute them.

[Gordon]

Okay, here's how mine are routed.  I can still probably take another inch or two out of the longer line, but it's not visible unless you squat down next to the bike. 

[Bob Wessner]

Thanks Gordon.

[Gordon]

Thanks Gordon.

You're welcome!  And that's not dirt on the engine, it's called "patina".

[Bob Wessner]

The most valuable and desirable antiques have patina. 

[Objectionableone]

Hi Gordon,

Any problems with Part of the fuel line being lower that the bowls?

Thanks.

Ben

[Bob Wessner]

Shouldn't be any. The "T"'s feeding the carbs are lower than the bottom of the tank, so any bends, dips, etc. along the way should not matter. Gravity working in our favor for once. 

[Gordon]

Hi Gordon,

Any problems with Part of the fuel line being lower that the bowls?

Thanks.

Ben

Nope.  It's not the downward bends you have to worry about, it's the upward ones that air bubbles can get trapped in.  I could be wrong, but I thought this was the stock fuel line route.

[Objectionableone]

Excellent.  Thanks guys - I'm going to go with gordons set up.

BTW - am I the only person who uses Tygon fuel line?

Ben