[mpcycledesign]

I purchased a basket 2003 RC51 a couple weeks ago and I'm diving in and doing the usual flapper valve removal and block off plates. On the front cylinder - there is a hose running off the right side of valve cover that runs to a little scavanger plastic bottle under the air box - the air box also has a rubber hose running into the same scavanger bottle - which has a drain hose that runs under the bike (on mine the drain hose is plugged). Does the RC really need this or can I just plug the air box like I did with block off plate mode and plug off the valve cover?

 

[SubSailor]

That's the crankcase breather storage tank and drain tube.
It stores the oil mist residue from the crankcase breather.
When you change the oil, just loosen the clamp and remove the plug and drain the line.
Then insert plug and side clamp back over the plug to secure it.

 

[trboboost91]

so it can't be removed??

not even if you run a tube pointing upwards and put a small filter on the end of it?

 

[SubSailor]

In that case I'd say...probably.
After all, cars in the pre-EPA years vented their crankcases to the outside, although they also had filters or air/oil separator screens to hold down the oil misting.

 

[jgos929]

Again I agree with some. It can probably be done but do it right or you could have a mess on your hands

 

[SubSailor]

When I drained mine during last oil change, there was quite a bit in the hose.
Now I don't know how long it took to accumulate that much as I didn't do the last oil change, but the service manual says to drain it more often if high RPMs are used frequently.

 

[BMW M 5]

I think that amount of oil residue in this breather line depends also of the state(health) of engine...Engines with more miles...will leave more oil in this tube...and also..if we put more oil in the engine than it's prescribed...or if motorbike fall down from the side stand...certain quantity of oil can flow in airbox...and then in this tube which is a sort of bleeder...