A Lesson In Simple Solutions

[SteveD]

You need 7mm I.D. (metric) fuel hose.
It comes in cloth covered type (pre 1985-ish?) or plain rubber type.
I like the plain rubber type, seems to age better cosmetically (doesn't turn grey and get frayed ends)
Both are available from BMW (by the meter) or most places that fix old VW's and such.

If you use the cloth stuff, use a very sharp knife to cut the hose then roll the cut edge in superglue.. No frayed edges.

[kmisterk]

You need 7mm I.D. (metric) fuel hose.

Thanks for the specification! All hoses on my bike on the fuel lines have hose clamps anyway. You’re suggesting that with the right size, you don’t need hose clamps?

you will see a large (13mm?) fastener on the top of the gearbox. LEAVE IT ALONE! Unless you are planning to rebuild your box, of course... (leave it alone)

Rob mentioned that this matters not as much, If at all, on the 5-speed tranny box?

What’s the reason for this warning? Out of curiosity and future-sight.

[gspd]

Sounds like your bike was subjected to a 1/4" amateur hose job.
The OE 7mm gas line(s) never had clamps, never needed clamps.

I haven't had a 4 speed apart in decades, but from memory, the allan bolts on top of the gearbox adjust the shifter forks.

[kmisterk]

Sounds like your bike was subjected to a 1/4" amateur hose job.
The OE 7mm gas line(s) never had clamps, never needed clamps.

Thankfully, this sounds like an exceedingly simple fix

I haven't had a 4 speed apart in decades, but from memory, the allan bolts on top of the gearbox adjust the shifter forks.

Ahh, yeah. Makes sense to warn against touching that bolt, then, unless you know what you’re doing and know it’s part of the process you aim to perform.

[Rob]

What’s the reason for this warning? Out of curiosity and future-sight.

Can't speak for the four speed box as shown but on the five speed box, you can remove the 13mm bolt as much as you like. it simply threads into the top of the casting and holds the airbox half casting retainers (early camshell airbox) or lower airbox casting (later rectangular airboxes) in place. In fact, with the later airbox, you have to remove the bolt in order to take off the airbox. The fixing to leave alone is the crosshead screw which is also in the top of the box. If you remove this, it will release a sheet steel oil channel which will drop into the gearbox mechanism and, should you try to use the machine before you have dismanlted the box to relocate it, cause horrendous damage.

Rob

[ME 109]

There is a recess in the cover of the 5 speed tranny that would accept the oil splash tray if it were longer. That means it couldn't fall out if 'the screw' was removed.
I wonder why bmw didn't make the tray longer.

[kmisterk]

Thanks Rob. I apparently glazed over that part on my first read through. Definitely don’t want that to happen in any form.