Wow quite few interesting things there, thanks!

Safety is high on the list. So yes sometimes we will keep our boots on. That river you showed Noël I would keep my boots as it did look quite tough and if the bike fall on my foot.... I know how it feels.

In others circumstances, we could use other shoes and gear to prod and walk the river and assess. Maybe carry the luggage by foot to the other side and cross the bikes one by one without any luggage....

In any case lots of good ideas and discussions in here. Lots to think about! As usual! :clap:

That seems a good approach, first walk it in your swimmers and check for boulders, then hand carry luggage to the other side, then put all gear back on including rain trousers, duct tape it tight around the ankles and on the zippers, open the throttle, close your eyes and pray! :helpsmilie:
The last bit I have to work on a bit I think. :smartass:

Chris Scott's Adventure Motor Cycle Handbook has a procedure how to prepare your bike for river crossings which are too deep to ride across

Assuming you have some sort of Enduro bike, like a Honda 250, etc, and that the exhaust is raised to just beneath seat level, can water actually do any damage to the bike, so long as it does not get down the tailpipe?

Depends where the inlet to the airbox is and how watertight the airbox itself is. Also, there are overflow / drain / breather hoses that run from carbs to worry about. Water won't go down the exhaust while the bike is running at a steady throttle but the induction side is vulnerable.

In theory, with the airbox sealed, fitted with a snorkel and the electrics waterproofed you could go as deep as you like. There's some footage on youtube of some chaps in Asia somewhere riding motorbikes underwater with just a couple of bits if pipe fitted to the inlet and exhaust.

Most enduro-type bikes that I have ridden with have happily managed water well above the engine. My DRZ will go scarey-deep; water up to the bottom of the seat without much trouble. I normally have to drain a little "bubble" of water out of the carb to get it to take full throttle afterwards but it will run OK otherwise.

Waterproof socks :D
 

http://www.sealskinz.com/UK/socks ;)

That's your feet dry...

As for the bike..

Carb breather pipes....
Air box and air box breather pipes
Exhaust
Tank breather
Fuel filler cap
Crankcase breather (the one everyone forgets)

These need to stay above water if you're submerged for any length of time. They can all be re-routed quite easily..

The old style canvas/rubber Lilos are a great way of floating a bike across a deep river, a pair of them tied together and lashed to the bike enable you to walk them across in anything upto to chest deep water - ideally use a guide rope as well. Keeping dry in those circumstances is irrelevant.

In fast flowing water you can use a rope tied to the opposite bank and then onto the bike and float the bike across using the power of the river rather than pushing/fighting your way across.

Prep the bike in case - plug the exhaust, pull the air filter and plug the inlet. Flood proof the electrics before you leave - spray silicone on and build up layers over a few weeks.

Clothing - if you know you will be riding in wet and cold conditions the majority of the time use a surfers wetsuit/steamer as your underwear - will keep you warm and a bit wrinkly if it gets wet inside but they can be lifesavers in low temperatures. Need to be dried out daily, downside is that they can smell.