Oil Breather Crankcase Cap

[loudest143]

Hello All, I'm looking for an Oil Breather Crankcase Cap. The cap would replace the stock dipstick cap in the crankcase. I'm having difficulty finding anything, fitting or otherwise, that I can replace my dipstick so my drain hose can mate up with the case like an aftermarket breather system. I'm building my own...

If you have any links, lemme know.

loudest143
*it's always happy hour somewhere.

[earlwb]

order the GY6 metal cap/dipstick from www.oregonvintage.com and drill and tap it for a fitting.
You can likely do it to the plastic ones too.
If you have access to a lathe with threading attachments, you can lathe one out easily enough too.
You can also get a compression release kit from vendors on Ebay that includes a oil cap already drilled and tapped for a fitting.
Like this one here:
tinyurl.com/yqshha

Here is a pic of the metal one at Oregon Vintage:

[natefromogden]

You shouldn't really require a return line to the oil system if your engine is working properly. When I ditched my stock airbox and the hose connection for the rocker cover vent, I built a catch can and installed it to my frame above the rocker cover. I used a plastic box with a snap lid, similar to a band-aid box with a air fitting epoxied in for the hose to connect to. Then I drilled a couple small vent holes in the top. The amount of oil that collects in that plastic box isn't enough to soak a paper towel that I put in the box to absorb any oil.

Its practically no oil that gets up into that box and certainly not worth the effort to create a return line back into the engine. This on a scoot w/ 5500 miles on it and that was getting run 25-30 miles per day at city speeds.

My recommendation? Build a simple catch can and a bracket to mount it to one of the unused mounts for the original airbox.

[loudest143]

Great info! I was speculating about the need for a return line... I know it's sort of the right thing to do, but not completely necessary, as there's not much to return. I also have an oil cooler anyways, so any temperature issues are not really there. Thanks!

loudest143
*favorite color: shiny

[HPS MotorSports LLC]

Here is a great way to route your breather hose from the head. I actually do this as a kit. I remove the airbox completely. I use a foam Unifilter and use the CVT breather hose from a 50cc scooter. it will have an vaccuum hose nub on it. I connect that hose with some PVC Pipe to connect the CVT breather hose pipe to the carb and the air filter. I route the breather hose from the head to the vacuum hose nub on the CVT breather hose pipe. This way what ever small amounts of oil go into the hose get burned up in the engine thru the carb. Ive done it on 5 other bikes and works great!!!. Of course on a 150cc scooter (the ones I have upgraded) I re-jet the carb from a 107 to a 114. I have gotten great results from it like an extra 15-20 MPH. I ve even had guys able to bury the speedo!! I am in the process of making these as kits. If anyone is interested email me at [e-mail]