Warning: This is a bit of a long, rambling post, and probably not of interest to those who rarely venture off the tarmac
So I went for a bit of a ride around Wiltshire/Salisbury Plain the weekend before last...
...which was great, right up to the point where I rode into this...
Not the best photo in the world, as it was taken one-handed while stood up to my waist in water and holding the bike upright with the other hand, but you get the idea. Rather deep, and full of sticky mud in the bottom.
Hit the kill switch immediately as it ground to a halt and before water could get into the airbox, so no concerns about immediate damage to the engine, but as it was sat there it did sink a bit more. Lifted/dragged/pushed/shouted/swore the bike back onto dry land and started thinking about recovering the situation.
Step 1: Drain the airbox - easily accomplished with a set of pliers to take the spring clip off the drain hose.
Step 2: Pump out the cylinder, because even though the engine wasn't running, there is water all up the inlet tract. Easily accomplished if you've got a plug wrench. As it happened I didn't have one on this occasion (but will in future), but that didn't matter because I also didn't have an answer to...
Step 3: Realise that all that water that was in the airbox has also been trickling down into the crankcases via the breather, and they are now brim full of watery mayonnaise with very little in terms of lubricating properties.
Now if I was SteveD, I'd be carrying my cooking equipment and a large enough pot to hold all the water and oil that is now in the crankcases, and I'd sit there simmering it gently until all the water evaporated and I was left with clean oil that I could pour back in, also replacing the filter with the spare I was carrying.
But with all due respect to our Esteemed Quartermaster of Everything, I'm not convinced by this plan for three reasons:
1) I don't carry all my camping gear around all the time.
2) I'd rather not spend all night huddled over my camping stove, and it is going to take a very long time to do that.
3) Over the last week I've flushed the engine through with a gallon of paraffin and two gallons of oil, and I'm still not entirely convinced I've cleaned it all out. It's not what you drain out into your saucepan that worried me, it's what's left behind.
So it seems like a better plan would be to try and avoid getting water into the crankcases in the first place, and it strikes me it wouldn't be that difficult or expensive to do - you just need to route the breather somewhere a bit less likely to end up underwater.
Somewhere up by the clocks would seem to fit the bill - if you ride into something that deep you're in a world of trouble anyway
, and even if you fall over in a more modest body of water the bars tend to keep the screen/clocks considerably higher than the airbox.
I don't think a brief immersion is likely to cause massive problems anyway - it's the fact it probably took me half an hour to drag the bike out to somewhere I could drain the airbox. For all that time there was a convenient reservoir of water sat above the top of the breather hose, and gravity will tend to do its thing in those circumstances.
There's a few options I'm weighing up:
1) Route the breather up to the top of the bike and stick a catch tank somewhere in the headlamp assembly. I'd expect the increased height/hose length to mean less oil escapes, but you'd still have to allow for a bit getting blown out.
2) Route the breather up to the top of the bike and then back down the other side to the front sprocket, removing the need for a catch tank (just do something useful with any oil that escapes)
3) Route the breather up to the top of the bike, then loop back down the same side and into the airbox - the system now functions exactly as before, but it's impossible for gravity alone to turn a flooded airbox into flooded cases.
The final piece of the jigsaw might be to stick a dry-break coupling at the high point of the breather where you can reach it - then if you really sink the bike you can unclip it (by feel and underwater if necessary) and effectively 'seal' the crankcases until you drag the bike back out.
Whichever I do will probably only cost a few quid, and will (in conjunction with actually carrying a plug wrench) minimise the chance of another six hour (or worse) recovery across the country.
Thoughts? Or should I just stop riding through puddles that I can't see the bottom of?