Crankcase vent bypass

[hogmolly]

I was looking at pictures of oil in the airbox, reading threads about the use of yamaha ring free with every tank, and threads about carbon. I went out to look at my bike and saw that the top of the engine vents into the bottom of the airbox in a straight forward fashion, so.....I have bypassed other bikes out of the airbox with good success (less blow by in airbox, less carbon on valves, ...) and wondered if anyone has done this to the ST? Does anyone make a kit (off road use only) that does this or do I need to blaze the trail myself?

I can't tell if the inlet to the airbox is pre or post filter so I'll probably just plug it off. My routing from the head will be up and down into a small PVC filter. This is a pretty common thing to do for hot rods and the like.

 

[Dogdaze]

I always had them installed on GSXR's or other high revving bikes, and did at one point of doing this, but not sure if I run high enough rpm's to warrant it. But would be interested to see your results, I may just do it.

 

[SilverBullet]

The inlet to the airbox is post filter so definitely seal it off good. Are people really finding a large amount of oil in the airbox? I get a little only, about 1oz/30ml every 30k miles/48kms. Fills the drip tube and puddles a little in the left corner. So the thinking is some of this oil gets sucked into the intake direct into combustion mixture?

I wouldn't mind having this engine vent relocated for ease of manintenance to plugs and checking valves. That hose is always a PITA even disconnecting on valve cover end. don't even think about disconnecting on airbox end. What type of filter is used? Are the one way valves clean or do they put out a little oil mist?

_

 

[hogmolly]

There is a bit of oil mist from the end. The normal "block off and vent" kits for dirt bikes have a check valve (like an old pcv valve) and a mesh filter at the end of the hose. Car kits usually just use a filter.

 

[Pterodactyl]

I extended the drip tube by about four inches by using aquarium hose of the appropriate size. The original cap fits on the end of the extension. I can easily see how much oil is in the tube, it lessons the amount of oil in the air box and it is easy to drain any oil in the tube without taking anything apart.

 

[hogmolly]

I extended the drip tube by about four inches by using aquarium hose of the appropriate size. The original cap fits on the end of the extension. I can easily see how much oil is in the tube, it lessons the amount of oil in the air box and it is easy to drain any oil in the tube without taking anything apart.

Clever. Do you have a pic?

 

[hogmolly]

I went out tonight after work and looked at my drain. This is what I saw after 2k miles (the bike is fairly new).

I took the lid off the air box and saw where the crank vents. It is below the filter and between the two Venturi's for the throttle bodies. I decided to borrow an idea posted above and did this

Now I can at least reach the drain bulb on the road or whenever I see it full

I appreciate some the ideas.