BMW K bikes (Bricks)

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k

k
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There are the two obvious ones that feed the injector rail, but there are two others, approximately starboard of the centerline, that have nothing connected to them and seem to be some sort of venting system. in tracing them, they seem to be part of an elaborate fuel tank internal tubing system that appears to be the product of much work and design.

I've had the bike for over a decade, and these lines have never been connected. Should they be? To what?

    

charlie99

charlie99
VIP
VIP
um  under the tank ?

please explain ?   a pic would help

on all models there are vents inside the tank , 
1 is the water bypass from the surrounding ring on the filler cap which passes through the tank directly ....drains accumulated water  straight through
2 is usually part of the tank ventilation system and on later models connects to a flexible tube that connects to the filter cage around the pump bottom , anti cavitation and equalising pressure  perhaps ?

86 models and later usually have a small cup attached to the frame that sits below the vent holes ...to catch the excess fuel and water ...a hose usually takes the contents out to near the swing arm , a safer place to dump fuel vapours ?

early models , I believe had 2 tubes taken from the vent spigots down to the same location and should be attached

the tell tale is the bolts used for holding the tank to the frame early models , or rubber spigot retainers mounted on the frame to accept locating spigots built into the tank later models

hope that helps ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OWhat are the Mystery Hose Nipples on the Underside of My 1985 K100RS Gas Tank Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

indian036

indian036
Life time member
Life time member
85 models can be either early or later type tank, depending on date and market sold into.

My June 85 (later) models have the 2 thick pins at the back of the tank, locating into metal sockets on top of the frame rails. The 2 outlets drain into the little plastic tray that Charlie spoke of, and the tray has a drain hose to the swing arm area.

The earlier model tanks are held on at the back by a central bolt into a crossmember attached to the frame.
In that model, there are (or should be) 2 hoses, both going back to the swing arm area.

I'm not sure, but I think the outlets are in a different place on the earlier tank, so retrofitting the later little tray may not work. 

Bill


__________________________________________________
1985 K100RT  VIN 0028991  My original Very Happy   (Historic rego)
1985 K100RT  VIN 0029036  BOB the Blue Old Bike  (Historic rego)
1990 K100LT  VIN 0190452  Work in progress
1984 K100RT  VIN 0023022  Work needing lots of progress

1986 K100RT  VIN 0090542  Work needing lots and lots of progress
1993 K1100LT  VIN 0183046  Work in progress
1993 K75S  VIN 0213045  Newest toy, slightly non-original
    

Dai

Dai
Life time member
Life time member
As Charlie says, they're the fuel and water vents. The front one is water and the rear one is fuel. The 'cup' that Charlie talks about is, AFAIK, a US-only invention driven by Californian emission regulations and is shown in the Clymer manual. Of the two, I've only bothered attaching a tube to the fuel vent and run it down under the bike near the righthand footrest hanger. I figure the water can boil off the engine.


__________________________________________________
'83 K100 upgraded to K100RS spec, '87 K100RT
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California
    

k

k
New member
New member
Thanks, folks.

Since these are vents and drains, I'm going to get some runs of tubing and bring them down by the swingarm.

    

Inge K.

Inge K.
VIP
VIP
@Dai wrote:The 'cup' that Charlie talks about is, AFAIK, a US-only invention driven by Californian emission regulations and is shown in the Clymer manual.

It's the other way around, Dai. Euro models have the "cup", then the vapours
from the fuel is able to reach out the atmosphere as it is a open system.....nasty, nasty.

On US models the fuel tank vent is directed into the crankcase via a one way
valve and a spigot on the front of the engine (close to the chain cover) and
then end up in the cumbustion chamber......was the idea.
But under unlucky circumstances you could get fuel into this ventilation system
and then it also ended up in the crankcase What are the Mystery Hose Nipples on the Underside of My 1985 K100RS Gas Tank 61740


Later on it was a couple of service bulletins about blinding the spigot on front
of the engine, remove the one way valve and connect a hose down to the RHS footrest bridge.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

Dai

Dai
Life time member
Life time member
Thanks Inge!


__________________________________________________
'83 K100 upgraded to K100RS spec, '87 K100RT
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California
    

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