airheads and water crossings.

But now " How to fix the problem"

The outside of the carb shouldn't be a problem. But the hole on the other side of the carb is behind the brass fuel line tube in a real tight space !!!

Any ideas ???

And yet, the air filter is completely exposed to the elements... I suppose at that point, water would be quite a bit higher.

You are right. Thats something i didn't get either.
Not making much sense to use that filter on a bike that should be able to go deep with the carb mods.

Any pics of the whole bike? It looks rather special.

I don't have a pair of bings right here in front of me to look at, but they use the same casting for both left and right side carbs, but then they machine them differently and affix the plastic name plate to make them work on one side or the other. My guess would be that only one of those vent holes actually goes anywhere. Someone want to check it? Either that or maybe they just plugged the one that'd be hard to put a breather on and called a single breather "good enough".

Thanks, Thomas. I guess I'll stick with the high pipe. Now if I can find an aluminum version maybe I could drop a few pounds.

The two small holes are breather holes. If you look inside the float bowl area up into the main body of the carb right below where these holes are yo see two more holes inside the main carb body. One of these can be plugged inside the float bowl area and the other vented to your hose. You should be OK with just one.

Here's some photos of variants in the 40mm carb. These come from here. Ironically it was Igormortis who made me aware of this site when I was having jetting issues & was considering using an air fuel meter.


Bing - 123, no idea where the breather vent is, sorry. Might still be the bottom of the float bowl?
Bing - 123a, vent is just below the plastic bing cover


Bing - 123a2. Breather port is the big cap above the riveted bing plate, & near the inlet. Looks like it would be relatively easy to take the cap off, & put a breather tube on that, or to create a spigot to take the breather much higher on the bike.

Hay Prutser,
another question. When you drown your bike on the Sibirsky trip your air filter probably got soaked. Were you using the standart paper one? Did you change and dry it? Or just ran the wet one?
Never had my bike that deep in the water yet so I'm curiose.
thanks for the answer.
cheers Thomas

P.S. My carbs are 32s from a R80G/S so I have the breathertube in the float bowl.

After succesfully drowning my old gs i learned NOT to use the paper filter. Since soon after the drowning mushrooms start to grow in there:eek1. And sand wil wear through the paper.
(Bmw used the paper filters on purpose so the paper would keep water from getting into the engine and cause damage. Something which saved my R100GS once)

I was using a uni filter (foam) on the Sibirsky trip! The problem with those is that they don't seal very well. Dirt is being sucked through between the airbox and the filter. To solve this I used a original filter, took out the paper and mounted the uni on top of the original filter. Made some longer clips to lock them together.

Now my air intake was against the bottom of my fuel tank.

A big problem that I would like to take care of is the water getting in when you make a big bow wave.
That was washing the dirt through the filter.

Just noticed this in the Baja GS replica thread:

Here's my filter setup. Made for me by these guys http://www.uniflow.com.au/

Yes I know, its a bit dirty

With the top lifted off. Still nice and clean underneath.

The underside. They use your old paper filter, cut the guts out of it and fit their own. As the fillter is flat, spares can be carried without taking up much space. I used to find with the paper filters there would always be a fine layer of dust on the inside of the airbox. Not so with the foam type.

That's a much better set-up than the ones for sale over here. Really like the pre-filter and easy to wash top.
The ones they sell over here have a soft rubber outside that slides of the edge of the air box.

I'm thinking about trying this.


And put some waterproof pre-filters over them when doing river crossings to deal with the splashing of a bow wave.

Some good ideas here.

Does anyone know if the standard airbox is the tuned, resonant type? Some reports seem to suggest that it is, due to loss of midrange torque when you start hacking holes in it.

I would be keen to modify the airbox to better deal with water, so long as the original characteristics can be maintained, or improved!

I've got the same problem with the UNI. Always wondered if there was a way to turn the horns, maybe with some vinyl hose and some how make it bend 90 degrees out to the sides, maybe put a bologna slice on the end so it will keep the water out. Rooney made it look very complicated....

<a href="https://hardwaregrrl.smugmug.com/Other/misc/16038929_6qzPj6#!i=2249805221&k=n86pqZt&lb=1&s=A" title="Photo & Video Sharing by SmugMug"><img src="https://hardwaregrrl.smugmug.com/Other/misc/i-n86pqZt/0/L/rooney-L.jpg" title="Photo & Video Sharing by SmugMug" alt="Photo & Video Sharing by SmugMug"></a>

I keep meaning to check if there's space for the cover to be mounted backwards.

I want to see the pics when somebody sinks their G/S so deep that they need their air filter that high.

In case you missed it...

Brad, you've got to check it out. I just realized I've suprassed your post count.....:eek1 I seriously need a job!!!

Come and help me paint my house so I can work on my bike so I can go to Siberia!