Dredging up an older thread for a relatively simple mod to increase wading depth on Paralever Airhead GSs (at least for bikes sporting 40mm carbs).
I have had issues with stream & river crossings where the carb float bowl breather blocks, the bike starts to cough, potentially you lose the bow wave, & the bike sucks water. Fortunately I haven't completely stalled mid stream, but it’s been close too many times.
One of the things we discovered earlier is that there are a number of carb variants, with three of these noted in post 48
, & so solutions for older bikes will be different / may be more difficult.
Prutser came up with a very elegant solution for his bike, back at post No 83.
My bike is a ’91 R100GS with 40mm carbs. The carb nos are 94/123a (left) & 94/40/124a (right). These have a round steel press fit cover over the external exit of the breather, on the side of the carb facing the engine block, adjacent to the choke.
The internal exit of the breather is at the top of the float chamber, & shown in the carb in the attached photo.
The press fit covers on the outer side of the carb are blanks.
I have had my machinist flick off the engine / choke side press fit covers, & then drill & tap a spigot into the breather tube. I have then run tubing up from the spigot, up the choke cable, & then onto the main frame of the bike to give a higher wading depth. Whilst not as cosmetically pleasing as Prutser's mod, I think this is an easy, cheap, & practical mod to resolve wading depth breathing issue.
Reassembled on the bike, the mod is not really visible. Be aware that I have yet to test this in an actual stream crossing, so it’s all hypothesis & theory at this stage.