Honda CX 500 Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
1,070 Posts
Discussion Starter · #1 ·
I read the following on the TAS motorsports website today. What are your opinions on this?



Most Bikes are gravity fed through a 1/4" or 3/16" ID fuel Line. A Filter reduces the diameter of the fuel line greatly since it slides inside of the line..



A paper Filter reduces flow greatly, and most are designed to be used with a system using a pump. We strongly advise AGAINST using an in line filter on anything over 300 CC's or more that 2 carbs.



Several fuel valves include a built in filter system including a screen, sediment bowl, or riser tube that keeps the valve from receiving debris from the bottom of the tank. Make sure your valve is in good condition, remove it and clean the area around the seal. Never run the bike on "reserve" since this is when it pulls from the bottom of the tank, and not through the riser.
 

·
Registered
Joined
·
1,867 Posts
I've never noticed any issues using my inline filter, but then again I have never NOT used the filter so I don't know if things would be better without it. I personally think an ounce of prevention is worth a pound of cure, if a filter doesn't hurt anything keep it on.
 

·
Registered
Joined
·
82 Posts
Ditto.



I have always used my inline fuel filter. I also know that my tank is slightly rusted inside and needs cleaning/lined.



Better safe then sorry though.



The bike has too much power for me to complain about the slight lack of fuel flow because of an installed inline filter.
 

·
Registered
Joined
·
195 Posts
A lot of people on this forum -- including me -- run tiny 1/4" inlet/outlet filters and I've never heard of any problems.



On my '99 Concours, I've tried 5/16" inlet/outlet filters, even with up-sized 3/8" fuel lines I still can't use a filter because it restricts flow too much -- it's a common problem with first gen Connies.
 

·
Super Moderator
Joined
·
15,399 Posts
Truth is that gas can only be used as fast as it can be supplied. If the supplying system puts out more than the bike can use there will never be a problem.



When I upgraded my tank from the stock early honda 14mm petcock to the 13/16th harley petcock the difference in gas flow is like using a fire hose when I only needed a garden hose. That and the other reason behind it was the aftermarket harley petcocks only cost $15.
 

·
Registered
Joined
·
8,423 Posts

·
Registered
Joined
·
32 Posts
My Cx was laid away for several years and needed a lot of cleanup/fixup due to near total neglect for that time. It sat in an unheated garage most of the time, quietly corroding away.

The tank was rusted inside and had to be cleaned and coated inside. A new fuel petcock and screen were installed and the carbs thoroughly cleaned. I thought all was well and when the bike was started, it showed signs of dirty fuel, even after all that. The carbs were cleaned out again and an inline fuel filter was purchased at the local auto parts store, along with a foot or so of gas hose the same size as the original short hose. Due to the lack of space for the filter under the tank, the hose was routed around the top of the intake air box, with the filter on the top of the air box. The hoses were easily connected and all was well after that, until.......

About two years later while returning from a trip to Luray, VA.,the bike began to show signs of fuel starvation near Fredricksburg, MD. It would not accelerate normally and only was able to maintain about 50mph on level ground. Since all that occurred in the middle of the night, we continued the rest of the way home.

I took the fuel filter out and opened it up. It was a paper filter and it had started to come apart. I flushed out the fuel lines and obtained a sintered bronze filter. It has operated very well since that was installed, and shows no sign of fuel starvation.
 

·
Registered
Joined
·
95 Posts
I'm running all three ( tank riser tube filter, fuel petcock screen filter, and inline fuel filter)--- has never been a problem, and carbs are clean and happy. Good info on potentail problem of using the fuel reserve ( at the tank bottom) though.

cheers Sam
 

·
Registered
Joined
·
1,354 Posts
I read the following on the TAS motorsports website today. What are your opinions on this?



Most Bikes are gravity fed through a 1/4" or 3/16" ID fuel Line. A Filter reduces the diameter of the fuel line greatly since it slides inside of the line..



A paper Filter reduces flow greatly, and most are designed to be used with a system using a pump. We strongly advise AGAINST using an in line filter on anything over 300 CC's or more that 2 carbs.



Several fuel valves include a built in filter system including a screen, sediment bowl, or riser tube that keeps the valve from receiving debris from the bottom of the tank. Make sure your valve is in good condition, remove it and clean the area around the seal. Never run the bike on "reserve" since this is when it pulls from the bottom of the tank, and not through the riser.
 

·
Registered
Joined
·
1,354 Posts
DUH??? The fittings the hose slips over on the petcock and carburetor are also inside the hose, so how does the diameter of the filter connections add restriction???


Any restriction from the filter would come from the filter media, especially when it is clogged with the various crud that would otherwise be in your jets.
 

·
Registered
Joined
·
498 Posts

·
Registered
Joined
·
307 Posts
One thing to remember. An in line filter will not solve all of your problems. Some work better than others. I used one on my newly cleaned tank. The tank still had rust in it which went through the filter. Had to clean my carbs the second time. The previous post will show what I am talking about.



http://cx500forum.co...ms/page__st__30


I agree, these `inline filters` are overated.

My Euro`s and the GL has an in-tank fine-mesh screen.

There`s a further mesh in the tap and a sediment trap.

Anything that finds it`s way past that lot isn`t going to be of a size that will `block a jet`.



I did try them a couple of times but although i never had any carb probs when i eventually removed the float bowls i still saw evidence of that extremely fine `silt` that collects down there.

Cheapo filters are crap - i`ve seen the element so loose a fit in the filter body that fuel (and any crap) just flows around the outside without getting filtered!



I`ve had needle valves not seating due to debris, but that has been down to flakes of fuel hose breaking off, and you can`t really avoid using a fuel hose..
 

·
Registered
Joined
·
498 Posts
Uppon closer examination, the screen was still in there! I built a puller useing a 3/8 x16 bolt. Drilled out three washers to 29/64 inside diameter. It worked real slick. Did not have to tap the screen, just screw in the bolt. Now I suppose that I have to replace the screen!















I am glad someone posted this problem before I put gas in the tank!
 

·
Registered
Joined
·
1,163 Posts
Perhaps for bigger motors using 1/4 / 5/16ths" lines, that "observation" may well hold true. For these gas misers?....NAH!!!!!!!



I'm SURE they took into account; 30 year old bikes........
 

·
Registered
Joined
·
195 Posts
DUH??? The fittings the hose slips over on the petcock and carburetor are also inside the hose, so how does the diameter of the filter connections add restriction???


Any restriction from the filter would come from the filter media, especially when it is clogged with the various crud that would otherwise be in your jets.


FYI: Restriction created by either length of run or ID of tubing are cumulative. So adding more smaller ID tubing will restrict the fuel flow. Even though the ID of the filter barbs is the same as the barbs on the petcock and carb, adding more of them does adversely affect fuel flow. In the case of the CX/GL, it's not enough to create a problem.
 
1 - 17 of 17 Posts
Top