Typically, at starting, I turn on the fuel petcock "on" , both sides, then start the
bike, and I see fuel seeping thru the braded lines (saturated), then leaking onto
the ground. (it appears that the float is not shutting off the fuel supply).
I replaced the float and pin, since this issue was occurring occasionally from last season.
The leaking issue remains.
What should I be checking here? Help!
'78 R100/7 '69 R69S '52 R25/2
if you determine that the fuel line itself is not the cause, then double check your assembly of the float and cap. It's possible to put the lid on there without the float stem inserted into the lever or, in the other type of cap, inserted into the fuel inlet itself. You've probably checked this already, but I've screwed it up so thought I would mention it.
I found that one of my floats (right side) was compromised and full of fuel. You say you just replaced it, so that's probably not the cause. FYSA, I ordered replacements from vintagebmwparts and also ordered some modern drop-in substitutions from Bob's BMW to use in a pinch: plastic 7g floats
In my lever type cap, the shut-off pin near the hinge of the lever had created a small dimple over time in the lever itself, such that the float was having a hard time making enough force to overcome the dimple, recess the pin, and shutoff the fuel. I smoothed it out as best I could and it seems to work more consistently now.
Obviously any debris in that pin recess area can disrupt fuel shutoff even if the float, lever, and pin are otherwise working correctly.
I don't know how helpful any of this is, but I feel your pain. I'm happy to report that as of today nothing is leaking...well, fuel anyway.
I had a similar issue on my 1972 R50/5 on May. The right side fuel line let petrol flow freely down. I managed to limit it by shutting down the right side petcock and got home unburned. I couldn't get a correct size braided fuel hose here in Brisbane (freaking imperial sizes everywhere) and got one from Sydney. It balooned with fuel on the first ride and leaked from every single piece of hose! Got my money back and put a simple plastic one. I'll get a period correct one when I have an order ready for Ulis.
Sold: 1960 BMW R27
Christos @ Brisbane, Australia