Hi guys! New day, new problem.

My bike has been sitting for 6 months and just got running again. In the past I noticed a small amount of grime built up around my 4th throttle body/intake that looked like a small leak. Now, it is a BIG leak. Its running all over the place. I have no idea if its even safe to ride. Any ideas as to the most common causes? 2 things: The pressure regulator vacuum hose that connects to the 4th throttle bottle is cracked and loose. Also, I feel like my fuel pump doesnt ever shut off. Or at least it never stops making noise.

local bmw mechanic said its probably a stuck injector? he also said a new injector is $200...
also, getting some misfires (doesn't appear to be rpm specific) and bike feels slightly underpowered.

If you can see fuel running out it's a fire waiting for a spark.  A check of the pump running all the time. Turn the key on then touch the start button, the pump should run for 1.5 sec then stop if the engine is not running, if the engine is running or even turning over on the starter the pump will be running and runs continuously.
Clean the area with degreaser and hose off and let it dry, start the bike and find exactly where the fuel is leaking from. Check your spark plugs to see if the #4 cyl is running rich, it woulde be very black and wet.
Send the injectors to get them serviced they will be able to tell you if any are faulty. Don't go buying an injector for $200. Thre are many cars that use those (mainly BMWs) and used good ones are readily available
To be honest it sounds like your mechanic is just too lazy to check where a used injector is available and goes to BMW because that is easy and he doesn't care about the price to you.

Ha thanks for tha advice. I tried to remove my fuel injectors but they are completely stuck in the engine.I've never removed them before, but I don't think this is normal. Is this a safety concern?

Before you attempt to remove them make sure there is nothing down the side of them that will fall into the port then engine. Clean around them using carb ans throttle body cleaner and compressed air taking care not to let anything get to the paintwork. Finish of using a vacuum cleaner with a small nozzle. The carb cleaner should have released the O-ring from its stuck position, if not soak and leave over night. You may have to work them around and be quite brutal but don't lever against the plastic parts of the injector

I offer another possibility if the fuel pump check is successful (i.e. it shuts off). If that was a fuel leak, I don't think you'd get the 'dirt stuck to a shiny bit' look because the fuel would evaporate. It could be oil. 'Slightly underpowered' and 'misfire' may point to a split vent hose between the airbox and the crankcase.

Okay guy, thanks for the opinions.

update:

I pulled the fuel injectors and rail.

Surprisingly, all the injectors actually look pretty good and are spraying pretty evenly.

The only thing I found that was weird is that the fuel hose (delivering fuel from tank to injector rail) never stopped dripping the entire time I had the rail off. I probably caught at least 10oz of fuel. This isn't normal, right?

Anyway, back to main problem (..unless that's my problem..) all I know at this point is that I have a LOT of gasoline leaking out of my 4th throttle body. New revelation is that although I definitely smell gasoline, I'm not positive it's just gasoline, because its leaving a pretty wet shiny cut on the engine, and if it were gasoline I'd expect it to burn off right away. 

Should I pull the throttle bodies? Is there anything in there that can go wrong?

mmmm... look to the post directly above you.

Still thinking cracked hose? Which hose are you referring to exactly?

also, while my fuel injectors are off should i do anything more? carb cleaner in the engine holes? Or just stick em back on..

The dripping is fairly common and nothing much to be concerned about so long as the injectors aren't leaking. Put new O-rings on the injectors at a minimum but preferably new pintle caps and filters in the top (tiny gauze filter about 3mm diameter in the top of the injector) Use an easy out or bolt extractor not sure what you call them but twist counter clockwise into a hole an extract a bolt that has been broken off.

To extract which Bolt?

bgambrogi wrote:To extract which Bolt?

Sorry not very clear. I meant to get the tiny gause filter out of the top of the injector you can use a small bolt extractor. It will grab hold of it and then you can give it a wriggle instead of trying to get at it with pliers and risk damaging the lip it seals against.

okay. I can try a new o-ring but they look to be in good condition. is there anything that can go wrong in the throttle body, itself, that could account for how black and leaky it is?

Dai wrote:I offer another possibility if the fuel pump check is successful (i.e. it shuts off). If that was a fuel leak, I don't think you'd get the 'dirt stuck to a shiny bit' look because the fuel would evaporate. It could be oil. 'Slightly underpowered' and 'misfire' may point to a split vent hose between the airbox and the crankcase.

Would this make sense if the leak is specifically coming from the 4th throttle body? I'll check.. Does anyone know which hose this would be?

Those that comes off the 4th throttle body (where the others are capped) looks to be worn and probably makes a poor seal. Also, the hose going into the gas tank on the left of the electrical port (not the hose bringing fuel to fuel rail) looks to have some small cracks in it. But again, the fact that the leak is only coming from one area makes me think the problem is local. Although now it looks like all of the throttle bodies seem to be leaking :/ but maybe they're just getting grime from the 4th one. Ugh...

Have a look at the first pic you posted at the end of the throttle bodies is a black electrical switch and behind it is a pipe that runs from the plenum chamber (on top of the throttle bodies) to the engine, that one is the one to check it needs to be air tight and not cracked.

good point keith

even some leakage of accumulated oil from the plenum could weep at that junction of the breather to the crankcase  .\\

so a couple things:

took off my gas tank and got some more light down below. as you can see in the picture, my leak is all over whatever hose this is. the picture is taken from between the third and fourth throttle bodies. image link:
https://drive.google.com/file/d/0BxjBsuob8jgFNm9sQTFHSWRMSDJzRWJPbEJGcTFUeG5TSXhB/view?usp=sharing


Also, the hose you guys suggested checking is, indeed, pretty weathered. only around where the rubber is clamped to the plenum, so hopefully I can cut some off and reuse the hose. this connection does not look the source of my leak.


...guess I can put my injectors back together now...

ah !! 

return fuel line ...the pic shows it coming off the fuel pressure regulator  as it makes its way back to the tank

replace all rubber to do with fuel is a must with age ,

this line is lower pressure so if you have leak on this one wonder what the lifetime of the others is like

at least 30 r 9   perhaps 30 r 8 at a pinch ? efi fuel line should be sought ... !!

by the way, I'm checking hoses.. none of the hoses on the RH side of the gas tank are plugged in. I see one disconnected with a screw stuck in it from previous owner, running to the hole in front right corner of gas tank. ...normal? im pretty sure this is not a CA emissions vehicle if that's relevant.

Actually, from the looks of it, there is no hose bringing fuel back to the gas tank. the front most hose on LH side connected to gas tank is dry (and a little cracked).

right hand side of tank ? 
there are none ... that attach to the tank ....there are breather tubes etc  that go down the right hand side of frame behind the tank towards the swing arm ,
and water overflow that goes under the tank from the filler under tank at the front to reservoir under sidecover

from riders seating position  the fuel leaves the tank on the  left, most rear spigot ....at the front of the tank
the return line should attach again on the left hand side  front most spigot.

um a little confused as to what pipes you mean exactly

but if the return line is stoppered up wow ...!!!

sorry:

on the RH side of my tank there is a valve/opening in the front, and another in the rear. The rear valve has a little catch tray sitting below it and seems to just be an overflow drain. I can't find a diagram that shows me what the front one is for, however there is a hose on my bike right below the opening with a screw stuck in it:
https://drive.google.com/file/d/0BxjBsuob8jgFZ29GeHRZZnphQUU/view?usp=sharing

closer view:
https://drive.google.com/open?id=0BxjBsuob8jgFZTlGWUZLNnA2MjQ


___
The return line in the front, LH of tank is correctly connected; it is just bone dry and cracked.

84 model ?

looks like a vacumme line ...on the early models there was a vacume switch located on the back of the throttle bodies ...that vacuume line pics off the front (first throttle body) ...which could be removed completely and a cap put on ?  as it has no real use and was discontinued on later models

the catch cup sits under the tank sort of in the middle to the back ?  and yes catches water from the filler surround (feeds through the tank ) and a breather from inside the tank ... so 2 small spigots ?

hope that helps


better take a pic of the under side of the tank for us   the right hand side spigot is confusing ?

If you find a disconnected purple/white wire (?? I think the tracer is white) then that will confirm Charlie's guess. The wire goes to the vacuum switch; leaving it out/off won't affect the engine at all. The idea was to introduce a secondary advance curve at idle but it didn't really work as most bikes were set to idle above the secondary curve rev range (did that make sense?). If it didn't make sense then you can blame a bottle of 15 year old Old Poulteney 'Dunnet Head' whisky.

well, as for the breather coming off the LH side (front?) of 1st throttle body, I believe thats a different hose. I lose them both near the radiator, but the "pull one, watch the other" test suggests they're different. maybe its just really pinched. anyway, I'm going to reinstall my fuel injectors. I just push them straight in while attached to rail right? I can't get them to budge inwards. my Clymer manual says to line up the injectors with their holes in the engine, then start tightening down the rail. I did that and one of the two bolt snapped off:(

Anyway! I bought a new crank case breather hose, too. Will install both, clean, and report back tomorrow. The BMW mechanic I just bought the breather hose from didn't seem too concerned that I wasn't seeing constant/regular fuel coming up the return hose, so I let idea drop for today..

I don't know what any of the stuff on the right hand side of my tank is, but my bike has been running for the year I've had it as is, so you're probably right about the vacuum hose. Charlie, you are correct about the catch cup.

Side note: I just let my gas tank sit on a table for a few hours. About a pint of gas came from fuel line, but no fuel anywhere else (was worried I had a little rust leak or something from the tank)

I had a similar issue and a replacement of the fuel lines and a replacement of the crankcase vent cured the problem for me.

As a general comment my advice if you get a K is replace all the fuel lines and the crank case breather/vent pipe. The fuel lines crack easily if old and hard.

yeah. do i need to take off airbox to replace crankcase breather hose? if so, I'll just do the fuel lines today too. 

I still can't tell if its gas or oil. looks like oil but there is way too much liquid coming out to be all oil from crankcase. I'm wondering if my fuel return hose and my crankcase breather are both leaking and making the problem together. The small amount of oil leaking from breather hose would cause the grime, the crack in the return hose (which I believe should run right between airbox and plenum?) would cause the leak, and this would explain why the top of my return hose is dry.


OLAF- when you say you replaced the "crankcase vent", are you talking about the same crankcase breather hose, or is that a different one?

Crank case vent as on breather hose. I was able to get it into place from the left said with a little jiggling about. A new one is nice and pliable and easy to wriggle in. Its got a groove in the outside of the moulding that seals up when its pushed home.

But to get at the fuel lines connections on the fuel pressure regulator I did have to take off the bottom off the air filter box, accessed them from right hand side. The bottom comes off separately, its got 2 Allen bolts in the bottom down into the top of the engine and they may be seized solid. That gave me enough working space.

bgambrogi wrote:yeah. do i need to take off airbox to replace crankcase breather hose?
No

Hello!
I a sum the part on the picture is what you are talking about.

Just take the old one of.
The hose has two sides!!! Remember how the old one set!
Put some oil on the new one, put both clamps on the hose first.
It's a tight place, but not to complicated to do.
Make sure the new hose sites correct and do not tighten it to strong, not good for the rubber.

Cheers

bgambrogi wrote:The BMW mechanic I just bought the breather hose from didn't seem too concerned that I wasn't seeing constant/regular fuel coming up the return hose, so I let idea drop for today..

He should have been .....when you push the starter button, or the engine
is running you should have a steady solid flow on the return.
If not...Your fuel pump doesn't function, or the pressure regulator is toast.

Chocolate wrote:

Hmmm........that's my kitchen table.

Inge K. wrote:Hmmm........that's my kitchen table.

Nice dinner,, the Scandinavians always have been eating strange food ;-) Inge
Could be Pinnekjøtt
Cheers

a ruptured diaphragm in the regulator or something is possible. i definitely have all symptoms of a bad pressure regulator, but lets just keep our fingers crossed on that;)


and to address an earlier conversation: my fuel pump is shutting off after one or two seconds as it should, but then once in a while when I'm riding or idling i hear a whining sort of sound coming from my tank (presumably the pump).

Hey guys, just wanted to give you guys the satisfaction of a conclusion:

The problem ended up being my fuel return hose, which had a huge leak right at the first bend. So replacing the fuel lines and the crank case breather hose took care of it. No FPR issues for no, fortunately.

This is a good example of the "measure twice, cut once" mentality. Had I taken the extra time in the beginning to remove the airbox, I would have found the problem immediately. Instead, I pulled the injectors first since they were the easiest to access...


Thanks for everyone's advice and time! Seriously appreciated.

Good news, all fixed