Question about 7mm fuel line

[james311]

I know this has been asked a few times, and I'm sorry for asking again but no one really answered what I was asking.

this link: http://www.hamuniverse.com/antfrac.html

says the closest size would be 9/32 which I am pretty sure Autozone or advanced sell that size, should I get it? Or stick with the standard 1/4th or 5/16 ( I went to the stealership today and they didn't even have the 7mm which I was ready to pay for).  I believe they also had 8mm, but that may be a little too big.


Also, should I be doing all my fuel lines? Only one has damage, from a friend+myself on separate occasions man handling it getting it out.


One more thing, pressurized hose? Non pressurized? Does it matter?

[dcclark]

I changed the fuel lines on my 2004 GS500F recently using 1/4" fuel line.  The fittings are larger than 1/4" and it was hard to get the new hose on.  I was able to get the line on the fittings with silicone lubricant.  I put an in-line fuel filter between the main line and the carbs.  My bike runs great around town, but on long highway runs at constant speed it seems to have a fuel starvation problem.

If I were to do it again, I would use 5/16".  The only drawback to 5/16" hose is that it may be difficult to attach at the tank where the fittings are close together.  I guess that's why one is longer than the other.

The lines are not pressurized so non-pressurized may be ok.  It may be thinner wall tubing as well making it easier to work with.

Good luck with your project!

[james311]

I changed the fuel lines on my 2004 GS500F recently using 1/4" fuel line.  The fittings are larger than 1/4" and it was hard to get the new hose on.  I was able to get the line on the fittings with silicone lubricant.  I put an in-line fuel filter between the main line and the carbs.  My bike runs great around town, but on long highway runs at constant speed it seems to have a fuel starvation problem.

If I were to do it again, I would use 5/16".  The only drawback to 5/16" hose is that it may be difficult to attach at the tank where the fittings are close together.  I guess that's why one is longer than the other.

The lines are not pressurized so non-pressurized may be ok.  It may be thinner wall tubing as well making it easier to work with.

Good luck with your project!

That's funny, the only line that is having a little bit of trouble is the "regular" (instead of the res line) at the tank connection, think I may just buy both of them. 1/4th and 5/16ths and see which is the better size.

What about just replacing that one line? Is it bad business to mix fuel line sizes?

[dcclark]

It's pretty low tech, I don't think different sizes will matter much.  I'd try the 5/16".  Easier to install and more fuel flow. 

Use screw type hose clamps.  I wouldn't trust the originals.  Remember if one of the gas lines falls off for some reason the fuel cutoff valve is under the tank.  You have to have a 12 mm wrench to get the back of the tank up to reach the valve and a long flat blade screwdriver to turn it off. 

[cole]

I bought the clear fuel hose(Tygon?) from my dealer, but Autozone sells similar. I used 1/4" and used a lighter and handle of a socket wrench to slightly enlarge the fitting. I gently heated(not melt or burn) the tube to expand the inner diameter. I don't recommend this next to the bike.
Also I have not noticed any starvation issues and the tube has not remained clear. It turns a nasty yellowish. I don't recommend car fuel line, that shaZam! won't fit and no matter how much you coax it.

[james311]

After all that I ended up being able to snip the fuel hose and simply pull it over, maybe an 1/8th of an inch of the metal fitting is showing.

[Kijona]

For future reference the best way to do this sort of thing is to boil a mug of water and dip the tip of the tubing in it and then immediately slip it over. It will soften it just enough to make it much more pliable without compromising the integrity of it. Using a lighter/torch/whatever is fine, the only problem is that it heats it unevenly and can cause a weak spot.

Also, the best type of lubricant to use on this sort of thing is two-stroke oil or just regular 'ol motor oil. It's not going to funk up your carbs and its lubricity is quite high.

[knowles]

Just did this today with 1/4 line i still use spring hose clamps, i also use a little bit of new oil on my finger and rub the flange of the fuel selector, goes right on.