Results 1 to 7 of 7

Thread: FUEL LEAK FROM VENT HOSES ... Follow-up on my inner-tank vent hoses!

  1. #1
    apriliaforum Member Aprilia13's Avatar
    Join Date
    Sep 2003
    Pacific NW

    Exclamation FUEL LEAK FROM VENT HOSES ... Follow-up on my inner-tank vent hoses!

    Any of you who have been around a while will have already run across one or more of these threads:

    In that first thread, I end up making a recommendation for replacement hose (post #13).

    In February, I got this private message from Fustern:
    Quote Originally Posted by Fustern
    Hi there,

    Was reading your post re: replacing the vent tubing on your Aprilia and that you used SAE 30R7. I read up on Gates specs for this tubing and they say not for submersion applications. The proper submersible hose is SAE 30R10. Anyway, the latter is something like $75-80 +to do the tank and pretty challenging to source locally in correct lengths.

    Is your repair still holding well with no drips from the bottom fuel vent lines? I'm guessing 2.5+ years now or so on your repair at this point?

    Also, which kind of clamps did you use to connect it to the fuel pump flange nipples? The regular generic worm drive clamps appear way too large to fit into that tiny space while still allowing the fuel pump flange to seat on the fuel tank properly.

    Thanks so much for the help!!
    And then, a couple months later, I began to get a slow leak from one of the vent hoses down by the exhaust, and would leave a pancake sized fuel stain wherever I parked.
    I began to feel sick to my stomach as I realized that I had potentially offered some harmful information, and could be responsible for some future trouble for anyone who followed my lead. My NAPA guy had sold me that stuff and told me it was gas-submersible, and I took his word for it. As has been pointed out by kzmille, OzMan2Downs, Fustern, and others, the suffix R10 is the appropriate hose, not the R7. However, the R10 is apparently WAY more expensive.

    Here comes the good news ... I no longer feel bad. What follows are recent pics of the hoses (now 3 years old) from my tank, which has been in constant use since I replaced the hoses in November of 2005. They are still in excellent shape, they are obviously NOT 'degrading' (as proven by the writing on the side), and the only sign of age is the milky-whiteness on the sides. Maybe oxidation, or maybe the beginnings of breakdown in the very surface? Whatever it is, it's minor enough after 3 years that I have no motivation to go out and get the 'proper' material. Even if it only lasts another 2 years, I'll be more than happy to spend $5 every 5 years, rather than $50 to 100 now.

    That's my report on that. Also, you'll see a pic of the clamps I used on the fuel pump end ... I used small spring clamps, which are small enough that they don't stick out too far. Also, if you look closely, you'll see that I moved them very close to the flange, and the end of the hose. You'll also see indentions in the hose, a tiny bit farther from the fuel pump, where the clamps had been for 2 and a half years. I have moved them closer in an effort to keep them from slipping off the fuel pump flange tubes, which are WAY too short, and do not have an expanded area near the end to encourage the hoses to 'seat' and not slip off. I wish I had thought to take a picture of the short connection tubes on the fuel pump before putting it back together ... they suck ... short and straight. My recent fuel leak had occurred because one of the hoses had worked it's way almost all the way off the metal tube at the fuel pump, and fuel was slowly getting out.

    But I am happy to report (sorry for the delay, Fustern ... I know I promised this months ago) that the hose I used is holding up very well.
    Attached Images Attached Images    
    Ride smarter, not harder!

  2. #2
    apriliaforum Member budturbo's Avatar
    Join Date
    Sep 2005
    Austell GA
    I bought mine from O'Reilly Autoparts. I was thinking the suffix was R9 but it might have been R10.

  3. #3
    apriliaforum expert Ozman2downs's Avatar
    Join Date
    Mar 2008
    I used some free stuff the Yamaha shop guys gave me. I guess they have rolls of it all the time they said. They use it in snow machines, jets skis everything Yamer. I think it is normally a buck per foot or something and 16 x2 inchs is all you need. No need for anything fancy.
    Victory comes with a price!

  4. #4
    apriliaforum expert Fustern's Avatar
    Join Date
    Jun 2005
    New Hampshire
    Wow man, thanks for the followup. I ended up cheaping out and got the NON fuel safe hose like you did. Glad to see its working well. Be careful of those spring clamps though. I first used those and even though they were very tight, they did loosen up enough to cause a bit of a fuel leak very shortly AFTER my repair job! So back in the tank I went. I bought some small fuel injector hose clamps (not the worm clamps) and so far so good. (Knock on wood).
    2000.5 Mille RSV 1000
    Leo Vince Slip on
    Pirelli Diablo Rubber

  5. #5
    %@*#&! hank's Avatar
    Join Date
    Jul 2003
    Worthy of being sticky?

  6. #6
    apriliaforum expert Ozman2downs's Avatar
    Join Date
    Mar 2008
    For fashioning the hose, stainless safety wire will do the trick too. Two arounds and a mildly snug tie. (Don't cut into line). The barb on nipple will hold hose in place. You just need a little tension below that.

    Lighter and much less expensive than stainless clamps or EFI clamps. And everyone has safety wire handy.
    Victory comes with a price!

  7. #7
    apriliaforum newb
    Join Date
    Sep 2008
    Outside of Boston
    Howdy, all. Yes, I too have been stricken with this problem. MY2000 RSV Mille, with the steel tank. When filling up with gas, it would POUR gas from the overflow hoses until at least 50% or more of the gas was drained from the tank. Enough was left in the tank that the fuel light did not come on, and I was able to ride home (after waiting a suitable amount of time for all the spilled gas to evaporate so I didn't became a fireball).

    After much searching and reading, I came across these threads here, and they've been hugely enlightening. Forgive me for the cross-posting, but since some of these threads are a few years old, I'm posting widely to try to get some feedback.

    Also, forgive me for my limited mechanical skills, but here's my attempt to summarize the problem:

    1. The vent hoses INSIDE the fuel tank break down (thanks to the ethanol in our gasoline), which cases them to crack.

    2. When I fill the tank, the gas INSIDE the tank will leak THRU a crack in the vent hose(s), pouring through the crack and down into the vent hose(s), until the level of the gas in the tank is below the location of the crack on the INTERIOR vent hose(s) (as noted by tipping the bike sideways, which caused more gas to leak, and centering the bike caused the leak to stop -- after the initial spillage had occurred). For example, if the crack in the hose is at the half-way point along the length, then the gas will leak until half the tank is empty.

    3. To remedy this problem I need to replace the vent hoses INSIDE the fuel tank (preferably with something that's rate SAE 30R10, though some have seen success and no issues with SAE 30R7 hoses).

    4. In order to do that, I need to:

    (a) Drain the tank. 1st QUESTION: per the workshop manual, I'm supposed to disconnect the fuel pipe at the quick-disconnect fitting, and then undo the hose clamp at the other end of the hose from the MALE part of the quick-disconnect, thereby freeing that length of hose from the bike entirely; by plugging the quick-disconnect back together, it opens the valve in the disconnect, which drains the tank; then reverse to reassemble, but the instructions say to buy a brand new clamp, since the old one will be unusable. Where can I get one? Aprilia part only, or can I use a new, generic one?

    (b) Remove the gas tank. 2nd QUESTION: do I need to disconnect the "fuel delivery pipe" (which is pressurized in operation) from the fuel pump, which in turn is mounted to the bottom of the fuel tank? Or can I just unbolt the fuel pump from the (upside down) fuel tank? If I do disconnect that pipe, the manual says to use two new gaskets. Are these standard gaskets, or do I have to order them from an Aprilia dealer?

    (c) Remove the fuel pump assembly from the bottom of the fuel tank. Use Loctite 518 on the o-ring gasket when reinstalling.

    (d) Remove the gas cap assembly from the top of the tank.

    (e) replace the interior hoses. The hoses are just friction fit to the gas cap assembly, but clamped to base plate of the fuel pump assembly base plate/flange? Or are they friction fit too? If there are clamps, does anyone have recommendations as to the type or size of clamp to use? Just match it to the new, replacement hose?

    (f) 3rd QUESTION: for reassembly, does one first attach the new hoses to the gas cap assembly, then reattach the gas cap assembly to the tank, and THEN attach the hoses to the fuel pump assembly base plate/flange? Or vice versa -- attach the hoses to the fuel pump assembly base plate/flange, reinstall the fuel pump assembly base plate/flange, and then attach the hoses to the gas cap assembly right before installing the gas cap assembly? This latter method assumes I can reach into the tank to pull the hoses out enough to slide the ends onto the gas cap assembly. But which way is easier/better/correct?

    I think that's it for my questions. Any and all feedback greatly appreciated - thanks!


    Boston, MA

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts