Hey Ya'll, Doin a few things to the 85rs that have needed tending to and I got a question that the local BMW dealer can't seem to help with. Its the hose that comes off the top of what I believe to be the fuel regulator (tucked behind the filter box) out to the left side of the fuel rail. It appears to be a special hose that has a hard glossy out shell with a softer inner hose. I know, sounds more like a candy bar...but the dealer ordered what he thought it was and it came in labeled vacuum hose and it doesn't have the glossy shell which I thought was maybe a heat shield of sorts. I've read posts on this very hose but none has talked about the hose itself...lest not that I could find. Any ideas?

30 r 8 is the minimum that you should use

the higher you go ...like 30 r 9 and then 30 r 10 has less chance of fuel vapours escaping the fuel lines ...actually you can smell the difference especially with unleaded and ethanol added fuels

just look for the recomendations for fuel injected fuel hose to start with ...

like all manufacturers some hoses are preformed ,,,,but on our old girls i dont see any reason not to use standard fuel lines cut to fit .

hope that helps

I would guess it's the vacum hose and not the fuel hose, Charlie.

As it's connected to the top of the FPR (and other end should be connected to TB#4)
The stiff plastic hose on the outside is to avoid that the rubber hose colapsing
under vacum, later models have a steel spring on the outside of the rubber hose.

Inge K, Please explain...TB#4?

The rearmost throttle body, the 3 other TB's have a rubber cap at the same place.

oops

i guess your right inge ....i should have had the specticals on

tb 4 ...= throttle body number 4 ....

Sorry, my mistake.....did look at some pictures, and the vacum connection is at the bottom of the FPR.
On the top of the FPR the return hose to the tank is connected..........
I'll go back and hide in my cave........

Don't go to your cave yet.... I'm way confused and the Clymer manual didn't make it clear to me. As I look at the TB from front of the bike to back or from left to right, the hose on the left on TB#1 goes around to what I think is the regulator and attaches to the top of it ....no clamps on either end.On the right side at TB#4 there is a hose that curls around to the backside and I think attaches to the bottom of the regulator but can't be sure till I get the bottom of the air filter box out of the way. Wish I could get a picture posted but that is a whole other topic. The hose on the front leftdoesn't attach to where those little rubber caps you mentioned are. Its in between the adj screw and that cap. The one at TB#4 attaches to where a cap could be. Hope all this make some sense.

There's a pic for you on page 2 of BlaKey's "my recently purchased RT" here half way down the page

The tube from TB#1 goes to a vacuum operated switch that in effect does nothing important and was so important that BMW didnt include it on later models so best to remove the tube and switch and disconnect the switch and leave the wire (it wont hurt anything if just left and tied out of the way)
The tube from TB#4 goes to the Fuel pressure regulator and is needed as it plays a part in adjusting fuel pressure at various throttle positions. Good idea to keep it in good condition as a leaking vacuum hose causes all sorts of problems.
When you remove the air box it's a good move to replace the fuel lines as they are probably as old as the bike, use the highest grade you can possibly get (30r 10) as the more modern fuels tend to permeate the older type hoses giving a fuel smell off.

I hope this makes it a bit clearer for you...

The bottom one is the formed hose from the regulator to the tank return.
The middle one is your vacuum line from the #4 throttle body around to the Fuel pressure regulator.
The 1st one is the proper "cut to fit piece from the fuel tank outlet down to the fuel rail and from the fuel rail around the back to the pressure regulator.
Most of us try to leave the one from the tank to the rail a little longer than required, so as to make moving the tank up & back easier.

16 12 1 180 409

FUEL HOSE - 8X13MM (meter)

0.32

X

$21.37

11 72 7 545 323

VACUUM HOSE BLACK - 3,5X1,8 (meter)

0.10

X

$16.00

13 31 1 461 011

HOSE

0.09

1

$20.82

I got a length of fuel line from BMW, about 1m long, it was quite reasonable and of course it's the right one. These fuel lines do perish in time and are under pressure so should be renewed.

You should get the 1 meter straight part that I showed you above AND the second one with the molded in curves ........goes from the pressure regulator back to the fuel tank.