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?

__________________
I spent a lot of money on travel and racing motorcycles - the rest I just squandered.

XT660Z - Commuter, Adventurer...Racer?

www.dashmoto.net

Other bikes >> MT-03 / CG125BR-J / ER-6F
Departed >> ZXR400L3 / EC300 / DR-Z400E / DR800S / GPZ500S / GS400

I would go with this option,,,,,, but,,,,

The LDNP (Lake District National Park) has just been working on a little known lane up here (The Old Coach Road) and decided to fence off the western section , by some trees, which means you now have little option but to ride through the 'puddles' which come up to airbox level in places.

With this in mind, I'm liking your ramblings.....

I have another 'thought', a short piece of pipe, with the correct diameter to fit into the breather hole in the airbox, with the end of a whoopee cusion fixed to the other end of the pipe. Then you have a sort of one-way valve, in the same concept as we use on the fish-tank air supply pump in case of power failure (so the water doesn't syphon out).

The problem is the whoopee cusion, it would probably melt with the heat of the hot oil, but if you could find the same profile 'closed' tube in silicon then you'd be sorted. A simple 'plug in' mod to solve the situation.

__________________
>-------<

Never underestimate the power of stupid people in large groups.

The thought of a one way valve had crossed my mind, but I'd veered away from it for a couple of reasons:

- I have no real idea where you'd get one that would be up to the job (not convinced by the whoopee cushion idea), whereas I know all sorts of places I can pick up a long bit of hose and a dry-break coupling.

- I would have thought the engine needs to suck a bit of air back in to keep the pressure equalised as it cools down when you stop. I'm not sure what would happen if you prevent that air coming in through the breather.

__________________
I spent a lot of money on travel and racing motorcycles - the rest I just squandered.

XT660Z - Commuter, Adventurer...Racer?

www.dashmoto.net

Other bikes >> MT-03 / CG125BR-J / ER-6F
Departed >> ZXR400L3 / EC300 / DR-Z400E / DR800S / GPZ500S / GS400

Don't forget you need clean air so you'd need a filter in there aswell.

I said Whoopee cusion really to explain the bit I was thinking of.

That's a fair point, hadn't considered that.

__________________
>-------<

Never underestimate the power of stupid people in large groups.

UT, I would run a pipe from the Crankcase up to the other side of the headstock to the filler. K&N breather filter on the end and job done.
How would you bung up the now open holes in the airbox? Big bolt and some epoxy resin?

I was musing on whether you could just loop the drain hose around and stick the free end on the breather entry. Haven't really looked to see what sizes the hoses are though, don't imagine they are obligingly the same .

__________________
I spent a lot of money on travel and racing motorcycles - the rest I just squandered.

XT660Z - Commuter, Adventurer...Racer?

www.dashmoto.net

Other bikes >> MT-03 / CG125BR-J / ER-6F
Departed >> ZXR400L3 / EC300 / DR-Z400E / DR800S / GPZ500S / GS400

Isn't the plug in the end of the breather drain pipe there to prevent water getting sucked up into the airbox? If the engine stops, it rapidly cools and the air inside the crankcases contracts, so any water in a pipe that leads into the crank cases will be sucked inside.
I once diverted the crank case breather on a Honda XL185S to the carb inlet rubber - motor side - using a cycle inner tube valve with nut to secure an airtight join. Any stray oil mist went straight into the cylinder to be burnt. Worked a treat.