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'04 R1150RT Fuel Leak - Was here, now gone

txmxrider

New member
Hello,

Wondering if anyone has any suggestions regarding a fuel leak. Here's the scenario: I started up the RT for the first time in a long time and immediately I smelled fuel and noticed a wisp of smoke coming from the right side. I shut it down and grabbed several fire extinguishers then started it up again and saw fuel dripping down onto the right side cylinder head so I shut it down again. I couldn't tell where it was coming from exactly because of the body work plus I didn't want to sit and stare at it too long for fear of staring a fire so I removed the bodywork thinking I would check it again with the tupperware removed so I could see where the leak was coming from but this time it didn't leak a drop when I started it. The only difference is that I have the fuel cap removed along with the bodywork. Would that make any difference you think? One interesting side note is that I see a fair amount of rust and peeling paint on the exterior of the charcoal canister. If I disconnect the hoses to the charcoal canister should I be able to blow through it freely? And if it was stopped up would that somehow cause a fuel leak? And maybe with the fuel cap removed it has enough vent that it doesn't leak?

Also, I attached a photo of my fuel line disconnects and I seem to recall that there was a problem with some plastic fuel line disconnects leaking and people replaced them with stainless steel versions from Beemer Boneyard. Hopefully the photo came through and if so can anyone identify if these are the type that leak and should be replaced?

I appreciate any advice and suggestions.

IMG_3312.jpg
 
Also, I attached a photo of my fuel line disconnects and I seem to recall that there was a problem with some plastic fuel line disconnects leaking and people replaced them with stainless steel versions from Beemer Boneyard. Hopefully the photo came through and if so can anyone identify if these are the type that leak and should be replaced?

The male ends look like the metal ones BMW sold and they should be good.
The female ends look like the original plastic ones.
It's possible you only need new orings.
To check for cracks in the black plastic female end turn the key on.
This will pressurize the fuel line and you'll see a mist of gas if there's a crack.
Put your cigar out first.

I don't know if BMW sells medal female ends.
If you buy some from Beemerboneyard they will fit your metal male ends.
If you only need orings and don't have a dealer close, I can mail you a few.
 
From the description of the location of the leak, the disconnects are the primary suspect. If the bike wasn’t started for a while, then the o-rings and the fuel hose could easily shrink because they dried out. After you got a little gas all around the connections, they had a chance to get lubricated and swell up, so the leak looked like it disappeared. Check all of the connections under there and replace the o-rings if you have them. Any time I separate the quick disconnects, I put a light smear of dielectric grease on the o-ring before I put it back together. Also, hold down the release latch when opening or closing the QDs. If you don’t, it is easier to nick the o-ring and get a leak from that.
 
I'll repeat what the previous two folks said: those factory quick-disconnects are your primary suspect. Either the plastic housings or their internal O-rings could be leaking. The O-rings are fairly easy to replace; the disconnects entirely are a bit less easy as they require quite a lot of tank draining to get the fuel lower than the internal lines. If you don't drain the tank before pulling the disconnects out, you spill gas. Ask me how I know.
That upper quick disconnect, which is for the fuel return line, looks suspiciously clean compared to the lower one. I bet that's it.

Another possible suspect is your fuel lines and their crimps; when was the last time they were replaced? The maintenance schedule says they're due every 4 years, but with quality gas (and no exposure to sunlight on your RT) they're probably fine a bit longer than that. If they're original to your bike they should absolutely be replaced (inside and out!), especially if you end up doing work on those quick disconnects. 17ish years is much too long.

Something else you mentioned is the presence of a charcoal canister on your bike. You should address that just because of the age of the bike. Your info says you're in Georgia, so you likely have the (easier and cheaper) option to simply remove it as you likely are not required by your state to undergo evaporative emissions testing.
If you are required to or want to replace it to keep the original evaporative emissions system intact, the part is still available from BMW but it is about $160 last I checked. The charcoal inside breaks down over time with exposure to gasoline and once it gets broken down far enough, it will make its way into the tank and throttle bodies. It could do everything from clog up your throttle bodies to clogging your fuel filter to killing your engine, if left to break down long enough, and when it gets that bad it is essentially fine graphite being sucked right into the intake stream with no filtration.
If you're cheap and crafty it's also possible to recondition the outside of the canister, pop it open, refill it with activated charcoal (which is the opposite of expensive by itself), and put it back in. That would also stave off the problem of charcoal breakdown.

On my own 1997 model with just 35k miles, one of the previous owners had removed the charcoal canister but had neglected to clean out the throttle bodies and they were very dirty; the insides were coated in black charcoal deposits.
 
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Thank you all for the info. I hope it's just the o-rings so I'll start with those. I was already planning to remove the fuel tank to replace the fuel filter and the fuel sending unit anyway so I guess I should replace the fuel lines too while I'm in there. The fuel sending unit stopped working a few years ago and I was putting off replacing it so I guess I'll rehab the whole thing. As I recall these fuel lines are very specific high pressure lines so I assume I should get these from the dealer, right?

Just wondering, do most people use stainless steel worm clamps for the various fuel lines or do you use the crimp on clamps?

I was reading the Clymer manual about how to do all this and it's clear as mud but I'll give it a go.

Lee...thank you for offering up your spare o-rings but since I'll be buying a bunch of other parts too I'll pick up some from the dealer. Thank you for the offer though.
 
Check your hoses for aging.
When they get old they shrink under the clamps and will weep. Especially where they exit the tank.
Do not use worm clamps, they are not up to the task for high pressure.
The existing crimps can be reused if levered open carefully with a small blade screwdriver in the loop from side to side.
Alternatively you can use a 13-15mm fuel injection clamp available at any automotive jobber.
 

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  • Fuel Injection Clamp.jpg
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As I recall these fuel lines are very specific high pressure lines so I assume I should get these from the dealer, right?

Just wondering, do most people use stainless steel worm clamps for the various fuel lines or do you use the crimp on clamps?

I'll repeat GSAddict here -- do NOT use worm clamps. They have a nasty habit of digging into the lines they're clamping onto when you tighten them and that is very bad for pressurized fuel lines! The fuel injection clamp he attached a picture of will work just fine, but you can also use the crimp on Oetiker clamps if you happen to already have a set.
Personally I went with both because I had access to an Oetiker set for free -- the stuff that I expect to change every so often like the fuel filter got the screw clamps, and the stuff I don't expect to change often got Oetiker clamps.

I did not go to the dealer when I replaced my lines -- you can buy or order all the stock external lines and most of the stock internal lines from any auto parts store, likely a lot cheaper. The external lines are standard 5/16 ID fuel injection hose, which is about $7 per foot last I checked. The Gates Barricade stuff I purchased from O'Reilly's is rated to 100PSI. I think I bought 5 feet and that was plenty enough.

The internal lines get trickier because of the weird U-bend that attaches to the fuel filter. Instead of paying over $50 for OEM pricing on a small bent piece of rubber, I bought an upgrade kit from Nushings for $39: http://nushings.com/#/moreproduct
This kit replaces the tight U-bend with a stainless steel U-bend and a pair of straight fuel hoses, which makes every piece of fuel hose inside the tank a straight piece of fuel line for much easier and cheaper replacement. It also includes a fuel pump plate gasket and the clamps which is very convenient if you're already going in there.

There is also another option for U-hose replacement tested by the folks at ADVRider, and sold by Beemer Boneyard, which replaces it with in-tank nylon bendy fuel line of the appropriate size. Beemer Boneyard's kit is pretty cheap, something like $14, but it's a little different than stock as the nylon lines they sell are rather long. You can order a very near-stock solution from Holley, part number 12-735HOL, for only $5, which can be trimmed a bit to match the length of the original U-hose and bends just as well. I did this before I eventually installed the Nushings kit. It does require two screw clamps that are smaller than the ones for the rubber lines, 9-11mm fuel injection clamps instead of 13-15mm.

You can order the non-bent in-tank fuel line from most auto parts stores but it is expensive no matter where you buy it. It's basically pure Viton (fluoroelastomer) and that is not cheap. I believe I paid $20 for the one foot I needed from O'Reilly's and they had to order it from a store 30 miles away as not all of them carried it.
The fuel line standard you want to see if you go that route is SAE30R10. It is 5/16 inch ID just like the external hose but is also rated for constant immersion in fuel. I needed less than 1 foot to do all the internal tank lines at first, and that was before I bought the Nushings kit which comes with even more of it.

So for a complete internal and external fuel line replacement and the one-time installation of the Nushings kit I paid something like $115 in parts, including all the clamps I needed, and I had plenty of line and clamps left over. I think I would've paid almost double that if I had bought the parts from BMW.

Hope that helps you out.
 
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Thank you senseamidmadness (and others) for the detailed advice and intel on the fuel lines and clamps. I was looking at an online parts fische last night and about fainted at the individual prices as I was putting together a parts list. I hope I'm not biting off more than I can chew with this project. The Clymer manual was difficult to follow but I watched some Youtube videos that clarified things a lot. One thing that is puzzling me is the purpose of the "sending unit". Presumably the float arm and potentiometer signals the fuel level to the gauge on the dash what exactly does the sending unit do? Sorry for asking so many questions!

Screenshot 2021-09-04 085408.pngScreenshot 2021-09-04 085549.png
 
Thank you senseamidmadness (and others) for the detailed advice and intel on the fuel lines and clamps. I was looking at an online parts fische last night and about fainted at the individual prices as I was putting together a parts list. I hope I'm not biting off more than I can chew with this project. The Clymer manual was difficult to follow but I watched some Youtube videos that clarified things a lot. One thing that is puzzling me is the purpose of the "sending unit". Presumably the float arm and potentiometer signals the fuel level to the gauge on the dash what exactly does the sending unit do? Sorry for asking so many questions!

Your dash has a separate LOW FUEL warning light. The float arm on the fuel pump plate controls that. The sending unit controls the fuel gauge bars on the (RID) rider info display.
 
One thing that is puzzling me is the purpose of the "sending unit". Presumably the float arm and potentiometer signals the fuel level to the gauge on the dash what exactly does the sending unit do? Sorry for asking so many questions!
The float arm and potentiometer go to the low fuel light in the dash. The sending unit goes to the fuel level gauge in the Rider Information Display.
 
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