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'12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 4:02 pm
by mchad
Parked at my office this morning, and put her on the sidestand. I basically always use the center stand, so this is pretty much the first time I have left her on the ss for more then a few minutes. I came out at lunch and noticed a 8" spot under the left peg. Not sure if the spot was there or not, so I moved the bike up a foot and went about my day. A few hours later, I came out and there was another spot, this time only an inch or so. I started looking and the only thing i found was a vent hose right behind the left foot peg. This has to be where the fluid came from. It appeared to be oil, but I could be wrong. I didn't notice any gas smell though, but it was breezy outside...
Anyone know what that vent is?
Last month, I may have overfilled the oil, for a day (I drained the extra 8 oz or so I put in the next day) I park in a garage where I would definitly have seen any leak, and never have seen a drop. But I always use the center stand. I am wondering if using the side stand allowed excess oil to drain? Or maybe it's not oil (I know I should have been more thorough)
Thanks
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 4:13 pm
by mogu83
This is basic put has to be asked.
You didn't just fill it to the rim with gas and leave it in the sun?
Other than that looks like you'll have to do the touch test and maybe even the dreaded taste test Recently I had a brake fluid leak in one of my vehicles and couldn't tell what it was (the new stuff doesn't smell and didn't recognize the taste) had to follow it back to the source to identify it.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 4:20 pm
by SF_Hooligan
That hose is likely the fuel vent hose, by way of the canister - if you've got one.
Was the first puddle still there when you went back and saw the second, smaller puddle? If not, it wasn't oil. As Mogu implies - this could be gas. When I fill my tank way up and put it on the sidestand, I get a bit of overflow from that hose.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 5:12 pm
by mchad
SF_Hooligan wrote:That hose is likely the fuel vent hose, by way of the canister - if you've got one.
Was the first puddle still there when you went back and saw the second, smaller puddle? If not, it wasn't oil. As Mogu implies - this could be gas. When I fill my tank way up and put it on the sidestand, I get a bit of overflow from that hose.
Hmm. The first spot was still there, yes.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 5:45 pm
by SF_Hooligan
Hmm... curious. Gas disappears pretty quickly.
First thing I do anytime there's something messy below my bike is put my finger in it. It's pretty straightforward to sort it from there, most of the time.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 6:07 pm
by KMalo
OK, I'm obviously new to R12Rs but if you overfilled the crankcase -- even if you drained some of the excess -- it's possible that oil vapors made their way to the air box. Could that hose be an air box vent?
I've seen this same scenario with other bikes, so assuming the RR has an air box drain, my guess is it's the bike self-correcting the after-effects of the overfill.
Chuck
Re: '12 r12r - fluid from vent hose by left peg
Posted: Mon Mar 12, 2012 7:29 pm
by mchad
KMalo wrote:OK, I'm obviously new to R12Rs but if you overfilled the crankcase -- even if you drained some of the excess -- it's possible that oil vapors made their way to the air box. Could that hose be an air box vent?
I've seen this same scenario with other bikes, so assuming the RR has an air box drain, my guess is it's the bike self-correcting the after-effects of the overfill.
Chuck
That makes the most sense to me, assuming... It could be that I was just assuming it came from that hose. Since this was the first time I sidestanded it, its possible the lean caused it to drain where being on the center it didn't. Which would also explain the diminishing size of the spills. I left her on the sidestand tonight, so Ill see whats what tomorrow. Since the garage deck is cleaner then the parking lot I was in, if there is indeed and residue, I'll do the finger test.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 8:15 am
by mchad
Update: This morning there is not a drop, and I left her on the side stand. And, it rained last night (and this morning) so I didn't bother trying to look at yesterdays spots at my office lot.
Oh well, it remains a mystery i guess...
Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 9:59 am
by mogu83
I guess you have to drop back to the "If it ain't broke - don't fix it" rule. Enjoy your ride

Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 3:24 pm
by Acpantera
I'd bet that it was an over filled or or real full gas tank that warmed and expanded. I've done it it several times....No worries.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 9:17 pm
by deilenberger
Acpantera wrote:I'd bet that it was an over filled or or real full gas tank that warmed and expanded. I've done it it several times....No worries.
The only worry with that is if you still have the charcoal canister (mine fell off somehow.. that's my story and I'm sticking with it..) for the fuel to come out the hose there has to be a LOT of raw fuel in the canister. That's gonna make for crappy idling once the bike warms up, and may eventually cause the charcoal to turn to mush and then get sucked back into the intake vent system plugging it up. When that happens - the fuel tank is no longer vented and you can collapse it, or at least cause bad running (as if you're running out of fuel.) This was fairly common on the oilhead bikes, leading to many people having their canister fall off.
Of course you don't want it to fall off whilst still under warranty. BMW can be touchy about things like that.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 10:16 pm
by mchad
I'm still not convinced it was gas. As I said earlier, when I came out 3 hours later the first spot was still there. Gas would definilty have evaporated in 3 hours. So, thats why I'm still thinking it was oil, for whatever reason...
Re: '12 r12r - fluid from vent hose by left peg
Posted: Tue Mar 13, 2012 10:54 pm
by SF_Hooligan
deilenberger wrote:Acpantera wrote:I'd bet that it was an over filled or or real full gas tank that warmed and expanded. I've done it it several times....No worries.
The only worry with that is if you still have the charcoal canister (mine fell off somehow.. that's my story and I'm sticking with it..) for the fuel to come out the hose there has to be a LOT of raw fuel in the canister. That's gonna make for crappy idling once the bike warms up, and may eventually cause the charcoal to turn to mush and then get sucked back into the intake vent system plugging it up. When that happens - the fuel tank is no longer vented and you can collapse it, or at least cause bad running (as if you're running out of fuel.) This was fairly common on the oilhead bikes, leading to many people having their canister fall off.
Of course you don't want it to fall off whilst still under warranty. BMW can be touchy about things like that.
I could be totally making this up, but I kind of remember a recent reference to the canisters being different now. When I first got my bike (2011) I filled up and left the bike on the sidestand for a couple minutes while I grabbed a cup of coffee in some little town up on Highway 1. Lots of gas on the ground, but it idled like normal when I fired it up.
Re: '12 r12r - fluid from vent hose by left peg
Posted: Wed Mar 14, 2012 9:32 pm
by Patch
mchad,
The same thing happened to me for the 1st time today. Yesterday I filled up right before I got home, parked in the sun (on sidestand) and left it til today. This morning an 8" stain on the driveway right under the left peg. Wasn't real wet, but very visible. In fact tonight it's still there.
Strong gas smell and not oily-feeling so I followed the rubber hose from the peg to the ... you guessed it... my canister. I couldn't bring myself to conduct a taste-test as mogu suggested
No issues upon start-up and ran like a champ all day today. What was odd is that I always use the center stand after a fill-up and park but for some reason I didn't do it that way last night. I'll blame the stupid fuel-strip for my forgetfulness.