Fuel leak after storage period

[jeffyjeff]

2002 R1150R,  51,425 miles.

 

Good day all.  One day during the summer of Covid (2020), I started my bike after a storage period of around 6 months.  Fired right up.  Everything was looking good until I noticed a puddle of gasoline pooling around the center stand.  Egad!  I shut the bike off and cleaned up the mess.  Subsequent inspection did not reveal source of the puddle, so I laid out some rags and started the engine to ascertain the source of the leak.  To my amazement, the problem magically appeared to correct itself... no leak to be found.  I cautiously put the bike into service, checking frequently for signs of leakage.  Eventually I forgot about it.  I've put 21,000 miles on the bike since then without recurrence.

 

Today, after an 11-week idle period, it happened again.  This time I was able to determine that fuel was running down the left side of the engine case, just behind the cylinder.  Fuel appeared to be dribbling from a location somewhere behind the alternator.  As before, I cleaned up the puddle and when I started the bike a second time, no leak, none, just like it never happened.

 

A quick check of my Clymer manual suggests the source could be the pressure regulator/fuel distributor (although I am unable to see these parts without fuel tank removal). Naturally, this assembly appears to be buried in a location with limited access.

 

My questions:

1.       Could the problem be related to one or both O-rings that appear to seal the pressure regulator to the fuel distributor?  There is a line drawing on page 315 of the Clymer manual. The drawing does not show how the assembly is held together, although the text states that a retainer clip secures the regulator to the fuel distributor.

2.       Do you think that it is significant that both times the leak happened after a storage period?

3.       Do you think that it is significant that both times the leak self-corrected after initial engine start?  I’m thinking a dry or stuck O-ring might allow fuel migration to an area it’s not supposed to be, and that once saturated with fuel, the O-ring either swells to seal, or moves to its proper position.

4.       Is it true that the transmission must be removed to access the fuel pressure regulator?

5.       How stupid was it for me to continue to ride the bike after the initial leak…don’t answer that.  What are the odds that this could fail while underway and turn me into a flying fireball?

 

I appreciate the knowledge, experience, and technical expertise of BMWST members, and hope someone can shed light on the cause and correction of this abnormal operation.  Thank you, happy Independence Day to all.

 

 

 

[RogerC60]

I had a similar leak on my '03 RT. It turned out to be where the rubber fuel hose from the fuel tank connects to the hard line input tube to the distributor. I removed the OEM clamp and installed a fuel injection style clamp from the local auto parts store. No more leak.

[dirtrider]

15 hours ago, jeffyjeff said:

2002 R1150R,  51,425 miles.

 

Good day all.  One day during the summer of Covid (2020), I started my bike after a storage period of around 6 months.  Fired right up.  Everything was looking good until I noticed a puddle of gasoline pooling around the center stand.  Egad!  I shut the bike off and cleaned up the mess.  Subsequent inspection did not reveal source of the puddle, so I laid out some rags and started the engine to ascertain the source of the leak.  To my amazement, the problem magically appeared to correct itself... no leak to be found.  I cautiously put the bike into service, checking frequently for signs of leakage.  Eventually I forgot about it.  I've put 21,000 miles on the bike since then without recurrence.

 

Today, after an 11-week idle period, it happened again.  This time I was able to determine that fuel was running down the left side of the engine case, just behind the cylinder.  Fuel appeared to be dribbling from a location somewhere behind the alternator.  As before, I cleaned up the puddle and when I started the bike a second time, no leak, none, just like it never happened.

 

A quick check of my Clymer manual suggests the source could be the pressure regulator/fuel distributor (although I am unable to see these parts without fuel tank removal). Naturally, this assembly appears to be buried in a location with limited access.

 

My questions:

1.       Could the problem be related to one or both O-rings that appear to seal the pressure regulator to the fuel distributor?  There is a line drawing on page 315 of the Clymer manual. The drawing does not show how the assembly is held together, although the text states that a retainer clip secures the regulator to the fuel distributor.

2.       Do you think that it is significant that both times the leak happened after a storage period?

3.       Do you think that it is significant that both times the leak self-corrected after initial engine start?  I’m thinking a dry or stuck O-ring might allow fuel migration to an area it’s not supposed to be, and that once saturated with fuel, the O-ring either swells to seal, or moves to its proper position.

4.       Is it true that the transmission must be removed to access the fuel pressure regulator?

5.       How stupid was it for me to continue to ride the bike after the initial leak…don’t answer that.  What are the odds that this could fail while underway and turn me into a flying fireball?

 

I appreciate the knowledge, experience, and technical expertise of BMWST members, and hope someone can shed light on the cause and correction of this abnormal operation.  Thank you, happy Independence Day to all.

 

 

 

Morning  jeffyjeff

 

1.       Could the problem be related to one or both O-rings that appear to seal the pressure regulator to the fuel distributor?  There is a line drawing on page 315 of the Clymer manual. The drawing does not show how the assembly is held together, although the text states that a retainer clip secures the regulator to the fuel distributor.--- There is a large (hairpin) type clip that slides in to hold the regulator in place.  

 

2.       Do you think that it is significant that both times the leak happened after a storage period?--- No, that is when "O" rings or loose hose clamps tend to leak. A slight vacuum forms in the system unseating shrunken "O" rings or loose hoses, or ???  Then at startup the pressure in the system re-seats whatever is leaking. 

 

3.       Do you think that it is significant that both times the leak self-corrected after initial engine start?  I’m thinking a dry or stuck O-ring might allow fuel migration to an area it’s not supposed to be, and that once saturated with fuel, the O-ring either swells to seal, or moves to its proper position.---No, see above.

 

4.       Is it true that the transmission must be removed to access the fuel pressure regulator?-- No, the air box should be removed to replace the entire regulator/distributor assembly but there are workarounds that involve cutting plastic lines. Personally I remove the air box & do it right. Just the regulator itself might be possible without removing the air box but it will a real pain. 

 

5.       How stupid was it for me to continue to ride the bike after the initial leak…don’t answer that.  What are the odds that this could fail while underway and turn me into a flying fireball?-- Your choice, lots of riders are riding BMW's that leak when parked long term but once they self-seal they don't leak again until the next storage period.

 

Fuel has a habit of ruining down hoses then following engine & transmission case seams or gasket seams then dripping from the lowest spot, so start by making darn sure that your leak isn't from the quick disconnects (most likely place for an after storage fuel leak). If not from there then you REALLY should try to identify the actual leakage spot/area before proceeding with a repair.

[Mike279]

My 04 had the fuel line fitting at the tank leak after sitting a couple of weeks.  It would self seal from being pressurized.  Fuel line had hardened some and was able to move just a bit on the fitting.  Made it look like the quick connects were leaking as the gas made it way down. Looking up from there things looked dry as the fitting had sealed and the gas had moved down the outside of the hose.  Looking in from the front I was able to see the gas leak and it seal itself in just a second or so.  Easy fix once you find the leak.  

[jeffyjeff]

Thanks all for the feedback.  I'll take the tank off this morning and poke around a bit.  The leak is definitely not the quick connects.  I could see dribbling from a point directly behind the alternator when peering in from the front left side of the bike.  Could be a tank connection, I suppose, or the aforementioned pressure regulator.  

 

If the regulator, perhaps I may be able to remove the alternator and access it through the front.  Won't know without further investigation.  Might be able to just replace the O-rings; they are 22 years old and must have lost some elasticity by now.  The regulator itself is working well, engine runs great.  If necessary, new pressure regulators are available $35 aftermarket or $120 OE from EME.

 

Good to know that other riders have experienced this same issue.  I feel a little less foolhardy after reading DR's comment #5 above.  Thanks again for sharing your experiences and observations.

[jeffyjeff]

Found the source of the leak.  Thanks Mike 279, you hit the nail on the head.  Once I got the tank off, it was apparent that the fuel pressure regulator and distributor are not located near where I observed the dribble.  It seems like fuel was leaking down the front of the ABS module and dribbling onto the engine case just behind the alternator.

 

I inspected the suspected leak path very carefully but could not find evidence of fuel flowing.  Stains around the fuel pump/filter base suggested something might be leaking from there, but nothing definitive that made me confident that the pump base was the source of the leak.  Upon reassembly, I decided to start the engine before bolting the tank back on.  No leak dribbling down onto the engine case.  But inspection of the pump base revealed a wet fuel line.  I tried to get a picture while it was still wet, but fumble fingers me could not manage to take a one-handed photo with my iphone while illuminating the problem with my flashlight.

Red arrow points to the area that was wet with fuel.  New clamp and I should be good to go.  Might be a good idea to replace the fuel lines outright.  As far as I know, they are all original.  Thanks all for your input.  Much appreciated.  Ride safe.   Jeff J.

 

[dirtrider]

33 minutes ago, jeffyjeff said:

Found the source of the leak.  Thanks Mike 279, you hit the nail on the head.  Once I got the tank off, it was apparent that the fuel pressure regulator and distributor are not located near where I observed the dribble.  It seems like fuel was leaking down the front of the ABS module and dribbling onto the engine case just behind the alternator.

 

I inspected the suspected leak path very carefully but could not find evidence of fuel flowing.  Stains around the fuel pump/filter base suggested something might be leaking from there, but nothing definitive that made me confident that the pump base was the source of the leak.  Upon reassembly, I decided to start the engine before bolting the tank back on.  No leak dribbling down onto the engine case.  But inspection of the pump base revealed a wet fuel line.  I tried to get a picture while it was still wet, but fumble fingers me could not manage to take a one-handed photo with my iphone while illuminating the problem with my flashlight.

Red arrow points to the area that was wet with fuel.  New clamp and I should be good to go.  Might be a good idea to replace the fuel lines outright.  As far as I know, they are all original.  Thanks all for your input.  Much appreciated.  Ride safe.   Jeff J.

 

Afternoon jeffyjeff

 

When you work on it, see if you can move that hose (twist then push/pull) if you can easily move it on the nipple then probably just tightening the clamp will stop your seep.  

 

If the hose seems tight then you probably should remove the hose from the fitting then cut off that same amount (plus a little more)  from the hose  then reinstall & tighten the clamp.  I have seen those multi-layer fuel hoses develop an inside liner pinhole leak then fuel comes out the end between the mid plies. Or just replace the hose or hoses. 

[jeffyjeff]

DR, Thanks for the tip.  Probably look at it tomorrow, today being Independence Day.  I'd like to use the OE Oetiker clamp, rather than a standard worm screw hose clamp.  While I'm at the dealer, I'll probably see about picking up 1.5 meters of submersible fuel line (assuming it can be used in free air as well as inside the fuel tank.)

[dirtrider]

10 minutes ago, jeffyjeff said:

DR, Thanks for the tip.  Probably look at it tomorrow, today being Independence Day.  I'd like to use the OE Oetiker clamp, rather than a standard worm screw hose clamp.  While I'm at the dealer, I'll probably see about picking up 1.5 meters of submersible fuel line (assuming it can be used in free air as well as inside the fuel tank.)

Afternoon jeffyjeff

 

I'm not sure that you want to use submersible fuel hose for those external hoses, you CAN, but you might get prepared for sticker shock when you ask the price. At least ask the price before they cut it for you, you might just change your mind. 

[jeffyjeff]

10-4. Been thinking about doing the internal tank lines for awhile now.  This might be a good opportunity to get it all done.  Thanks for the heads-up on the price.

[jeffyjeff]

Here is the hose that was leaking.  In the end I replaced both lines coming out of the pump/filter base.  Must have been hemorrhaging under a bit of pressure for the fuel to migrate over to the front of the ABS module and dribble down the left side of the bike.  I would normally expect fuel to follow the line down to the quick connects like it did on Mike279's bike.  Thanks for the tip on the submersible fuel line.  Local dealer was out of stock, several auto parts stores didn't carry it either.  Checked out Amazon:  $44 a foot!  Eeeeooww!!!!  Guess I'll leave the internal fuel lines alone until there is a definite problem in there.

[Redfoxx]

On 7/6/2023 at 8:38 PM, jeffyjeff said:

Here is the hose that was leaking.  In the end I replaced both lines coming out of the pump/filter base.  Must have been hemorrhaging under a bit of pressure for the fuel to migrate over to the front of the ABS module and dribble down the left side of the bike.  I would normally expect fuel to follow the line down to the quick connects like it did on Mike279's bike.  Thanks for the tip on the submersible fuel line.  Local dealer was out of stock, several auto parts stores didn't carry it either.  Checked out Amazon:  $44 a foot!  Eeeeooww!!!!  Guess I'll leave the internal fuel lines alone until there is a definite problem in there.

This is too late for you likely Motorwerks.uk  sells the hose for about $28 a meter for internal high pressure (8.61 a foot) .  I ordered mine with other parts so I dont know how much shipping would be just for fuel hose.