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YZ250 setup for river crossings

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I've recently purchased a 2008 YZ250 and am in the process of setting it up for pure bush riding.

With my last bike (2004 WR450F) I needed to reroute the crank breather to the airbox and put t-pieces in the carby vent lines so that the bike wouldn't stall during river crossings, or suck up water if it needed to be restarted mid way across.

Does anything similar need to be done to the YZ to ensure that it crosses up to knee-high water safely?

Thanks for any suggestions

Peter

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Whether or not it's a good idea, I've taken mine through pretty deep water several times a year with the stock hose routing. I've never had any issues.

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I would at the very minimum route my crankcase breather into the airbox or somewhere out of the water.

Chances are it will never suck any water.

But if you ever blow a crank seal..

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So it sounds like the 250 engine isn't prone to the same stalling issues that the 450 had when ends of the carby vent pipes were immersed in water - that's great.

I'll reroute the crankcase breather to be on the safe side.

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So it sounds like the 250 engine isn't prone to the same stalling issues that the 450 had when ends of the carby vent pipes were immersed in water - that's great.

I'll reroute the crankcase breather to be on the safe side.

I wouldn't say it stall prone but it definitely bogs if you get the cab vents in water. I did about 10 thigh high crossings on a ride early this year, and it bogged and sucked a bit of water into the crankcase.

T fittings in the vent lines is probably a good idea if you are trying to be on the safe side.

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No worries - I'll do the T fittings too then. Thanks for your help

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I've recently purchased a 2008 YZ250 and am in the process of setting it up for pure bush riding.

With my last bike (2004 WR450F) I needed to reroute the crank breather to the airbox and put t-pieces in the carby vent lines so that the bike wouldn't stall during river crossings, or suck up water if it needed to be restarted mid way across.

Does anything similar need to be done to the YZ to ensure that it crosses up to knee-high water safely?

Thanks for any suggestions

Peter

Do exactly the same for the smoker:thumbsup:

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I also would use some rtv on the rubber fitting where cables of the staor leave the crankcase. Not nice when the Magneto get dirty.

I was just looking at that fitting about 10 minutes ago and wondering if I should silastic it - thanks!

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You don't need to add the Ts. The vent lines are already Ts. Just run the upper two up into the airbox and leave the lower two down. No more stalling. I do the crank case vent up as well.

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You don't need to add the Ts. The vent lines are already Ts. Just run the upper two up into the airbox and leave the lower two down. No more stalling. I do the crank case vent up as well.

Damn - I just ran down to the local hardware store and grabbed a couple of plastic T's before I read this...Don't those hoses also allow draining when you drop the bike?

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It'll still drain out of the lowers. Add the ts if you want. Seems many do but it's not needed. Look at the carb. good. See where the current vents go into the same spot? They are ts.

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It'll still drain out of the lowers. Add the ts if you want. Seems many do but it's not needed. Look at the carb. good. See where the current vents go into the same spot? They are ts.

Yep, just had a good look and you're right - seems that the upper hoses are just begging to be moved up to the airbox, so that's what I'll do, thanks!

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Next question concerns the large drain opening at the bottom of the airbox.

Has anyone had water ingested into the engine because of it getting in here?

I'm not planning to cross any rivers that are too deep, as I realise that the airbox is very open at the top half, but I'm also concerned that it may fill up via the drain during fairly shallow crossings.

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I made a small scoop out of aluminium and rivited it over the opening so that the open end is facing the rear spring mud flap but not touching it, that way when I do water crossings it actually draws any water out of the airbox.

It only needs to be about 12mm high so it can still draw air when normal motoing.

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That sounds interesting - did you put 'sides' on the scoop too or just leave them open.

I found this thread too a few minutes back (should have searched on 'airbox' earlier!), and it seems that the openess of the airbox is actually an advantage.

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Yes I put sides on the scoop also and put a kicker lip on the open side to help the draft.

You may also want to make sure your airfilter holder is siliconed into the air boot, water tends to get between this joint.

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