Hi all, Ive just started her up and a fuel line has just gone pop / bang - its the one whilst looking at the bike side on to the left which leaves the fuel rail - or does it enter the fuel rail??  i thought this hose went back to the tank? so before i strip her down is there anything i should be aware of?? 1984 k100. thanks Tim

It goes to the fuel pressure regulator - and then back to the tank.

How to get to the FPR:
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/maf/maf.htm

Once you get the MAF out you will have access to the FPR.

You'll probably want a couple of BMW 13mm hose clamps to replace the Oetiker clamps that hold the fuel lines to the FPR.

Thanks Duck, do you think after sitting for seven years this hose was just past it? i guess this is the case. Thanks Tim

That would be my guess.

Probably teaching me granny to suck eggs, but change all the fuel lines while you're in there. Be aware that the one on the rear spigot of the fuel tank is 7mm ID (thanks BMW) but an 8mm ID line will go on and not give trouble if you clamp it up properly with a worm drive.

We just put a new one on Magda's K100 last weekend.

I had some BMW line in my shed, 8mm inside diameter, 13mm outside diameter. If you are getting a non BMW one make sure its rated for fuel injection and you need at least 60psi because that's what's coming from the pump to the fuel pressure regulator.

I agree with Dai but for one small part. I also got the 13mm clips, but they are too small and fiddly to get them on and took them off and went one size up. You need 6 clips.

When you put the new lines in make them longer than the original ones by about 1 1/2" or so and you will be able to slide the tank back without disconnecting it to access the radiator coolant filler and you will also be able to lift it enough to access the relay box without disconnecting it. The pipe at the very front just behind the radiator should have an insulation around it.

I managed to do mine by just removing the bottom half of the air box. But there are 2 allen bolts inside bolting the bottom down to the top of the engine......WD40 them to get them out and liberal copper grease when you are putting them back.

While you are in there it's easier to get at the crankcase breather pipe and its small money so if in doubt swap it.

Again many thanks chaps - this is defo the most helpful forum

I use 5/16 (7.9mm) ID FI fuel lines on my bikes and the 13mm BMW hose clamps fit fine on that.

Well that air box is a joke.     :hp:But all done apart from ordering a new air filter, I might as well have ordered every spare part going haha