What's this hose ? # 38.
 

I accidently pulled it off while cleaning the bike. I noticed it's full of oil and is capped at one end. can anyone tell me the purpose of it ? is draining it part of a maintenance routine ? it's attached to the airbox of my 99 XT600E. in all my years of biking I've never seen such an elaborate airbox design !

http://i70.photobucket.com/albums/i8...orino/IMGa.jpg

I think it's the collector/outlet for any excess oil from the frame-oiltank. Any overpressurisation of the oil system pushes excess oil out of the top of the oiltank and into the airbox - this drains out of the bottom of the airbox and collects in this tube, hence the stopper in the end. Periodically remove the stopper and drain any oil.
:thumbup1:

I haven't the foggiest on this one either but the pipe you refer to pottsy is part 40 I believe.

If I was to hazard a guess I'd say that part 40 deals with day to day excess waste disposal in a metered way>>>note pinched end>>> I'd then hazard a guess that the pipe you are refering to is for such instances when you need to do a major drain off of the box such as if you had just drowned your bike on a river crossing or such. But that is a guess.

Or is it that #40 is for the BigTimeDrainings (:oops2:). I say this as the overflow pipe from the oiltank enters the airbox directly above the outlet pipe #38, whereas the #40 is the other side of the airfilter where the oil (hopefully...) doesn't get to. I think!

Thanks pottsy and bruken. good thing to know and add to my maintenance list. beats cleaning a huge puddle of oil off the shop floor next time I clean the air filter !

I would agree with Pottsy - the pipe #38 is on the carb side (after the air filter), which means the crankcase is venting back into the engine -essentially keeping those nasty fumes that Californians particularly hate, away from the atmosphere, while pipe #38 collects any excess oil... (I'm presuming the pipe is clear so you can see if it is filling up, and then drain it? - it is on my new Tenere anyway...)

Pipe #40 is similar to those found on virtually all dirtbike airboxes, and is simply for emptying out any water and crud that might have found it's way into the top of the airbox (before the air filter)... as Pottsy says, you don't really want oil on that side of the air filter (if only for environmental reasons) - although a number of dirt bikes do vent the crankcase into the pre-airfilter side as their airbox is simpler in design, and their air filters tend to be cleaned a lot more regularly anyway...

xxx

Well, I believe you guys to be right. On consideration Pottsy's counter argument makes more sense.

I only found all this out trying to sort out my xt's oil-leakage, otherwise i'd be non-the-wiser myself! It's an xt learning curve...

38
 

38 is for any excess oil to come from the crankcase to the airbox and back to the pipe you highlighted. periodically pull the plug, drain any oil and refit, it's normal. I'm in Africa on my 03 xt and have to do it regularly.

www.horizonsunlimited.com/tstories/geoffshing