Fuel Filters

[mack]

Haven't had many good days to run him this year, anyway I took Hermes out for a long run today. He started ok but I felt something was different. about a mile from home. Ran good under load but was not swooth as usual under 3k. was able to dial him up to 120 a couple times in traffic but just didn't feel right. Got him home and checked for crimped fuel lines. Everything looked good, but noticed air bubbles rising out of the fuel filters. Sat and had a beer and watched the lines and bubbles and the filters were bone dry. I got them from the dealer and specifically asked if they could keep up under load. My question is what are you guy's using, and have you had any problems. Hermes ran like a scared cat until I put filters in now he stumbles in the lower rpm but will dance above 4k.

[TopCatGr58]

We've used some from MikesXS.net, also just from the local auto store in the small engine section, ones for lawnmowers are okay, look like little cones.

There is a flow direction arrow on them...are you sure you put them in the right direction?

However, if you were able to get it up to 120mph, then sounds like you're not starving for fuel....takes a lot more to keep them filled under that speed/rpm than at idle and low rpm.

A test you could do is take them back out and see if it still runs strong or weak. If weak, then it's most likely not the filters, and you can then look to other problems...ie. spark, vacuum leaks, timing, etc.
T.C.

[mack]

fuel filters

Thanx TC, flow arrows are in correct direction, no kinks in lines, but the filter bowls were completely dry when I stopped the bike.I'm taking them back out, but what a pain. Now have to pull the carbs to cut new lines from "T" 2 "T". Was easy to install them as all I had to do was drop the lower filter box and reach in with a set of side cutters and knock off about an inch per side and slip the filters in. Won't be that easy to take them out. At least I'm using Tygon.

[jetmechmarty]

I'm running a pair of Visu Filters without any fuel starvation issue, even at WOT.

I bought them at my local motorcycle shop.

[mack]

filters

The ones I have say "tw fastex" on them and are a 90 degree.The filter almost looks like a conical chunk of gold dust inside. Another week of rain in forecast so will have time to pull carbs and run new lines.

[TopCatGr58]

Hey Mack,

It's a variation of the VisuFilters, with a porous bronze filter element, and 90 degree nipple.



The arrow does show it flowing from the SIDE nipple and out thru the one at the large end. Surprised that it wouldn't flow. You can try blowing thru it by mouth once you have it removed to see if it's gotten clogged.

T.C.

[mack]

thats it

Yep, thats the one, I still have the octy installed, I can't imagine that would make any difference. I'll see if I can pull them out and suck on them to see if they are plugged but I bet I don't have 100 miles on them. Could have been junk before I installed them, should have checked then but never thought of it.

[CaptonZap]

Yep, thats the one, I still have the octy installed, I can't imagine that would make any difference. I'll see if I can pull them out and suck on them to see if they are plugged but I bet I don't have 100 miles on them. Could have been junk before I installed them, should have checked then but never thought of it.

Slow down, dude, first rule in filter checking is "blow, don't suck". CZ

[TopCatGr58]

Aha the plot thickens,

Check the vacuum line to the OCTY, and that one you WOULD need to "apply suction" to it to test it's flow and be sure it isn't cracked/leaking.

But before you do that, put the petcocks on PRIME and test run it. Prime essentially bypasses the OCTY functions, and IF the problem goes away, then you know it's NOT the filters, but perhaps the Octy...a vacuum leak, or stuck/sticking/slow diaphragm that opens MORE under higher rpms/loads than at idle/off idle!?

T.C.

Yep, thats the one, I still have the octy installed, I can't imagine that would make any difference. I'll see if I can pull them out and suck on them to see if they are plugged but I bet I don't have 100 miles on them. Could have been junk before I installed them, should have checked then but never thought of it.

[WMarshy]

These filters are not good for our bikes. They get plugged because they are too fine of a filter. I suggest staying with a paper type or screen type filter. They don't have to get fully blocked before they can't keep up with the fuel demanded... toss them and get something like jetmechmarty shows...

[Diskman01]

Whatever filter you use, do NOT accidentally install them backwards if you are re-tubing. Especially if they are a few years old. I got a chance to get up close and personal AGAIN with the carbs on my CB650 after pulling that stunt last year.

Double check the flow people. Will save you an afternoon of prime riding time rebuilding carbs that are choked with rusty paint chips.

[Incubus]

And make sure they installed vertically. If they are horizontal air an pocket can form and stop fuel flow.

Patrick

[mack]

Gee, I wouldn't have thought it would have made a difference. However both were installed the same and one filled and one didn't. I will pay attension to this the next time.

[TomRodgers]

this is what I'm running....

I have a pair of these from Summit Racing with tygon line. look good and work good too!!!



Hope it works this time...posting the picture that is....

If not, they are Spectre 2369 filters...they have several barbed tip sizes to choose from. Filter elements are replaceable.!!!!!

[Mendizale]

Is it possible your petcock is blocked, or not functioning correctly? Might explain the asymmetric flow rates your experiencing.