Crankcase breather

Previously ralph_eborn wrote:

I know this is a well discussed subject but can anyone tell me what isthe best type of one wayvalve (if any)to fit in the crankcase breather pipe on a late 750 roadster, and are there any recent develpopments on this?

thanks, Ralph.

For my 72 I have bought a reed valve from MikesXS to replace the original, will also move the oil pickup back to the proper place.

Holland Norton Works also list the reed valve.

I have the Yamaha XS 650 valve fitted to my bike and it works well. Mikesxs gets some pretty bad press when it comes to mail order. I got mine from XS650shop.de a specialist in Germany, ie a little closer than the USA

Previously iain_brown wrote:

Holland Norton Works also list the reed valve.

Thanks for that. Have bought one from them; good service.

Hi Guys, Does the PCV valve fit inline of the hose from the rear of timing case to top of oil tank? Cheers, Tony

Previously antony_ryan wrote:

Hi Guys, Does the PCV valve fit inline of the hose from the rear of timing case to top of oil tank? Cheers, Tony

Yes.

I think that all the usual sources of these valves are out of stock until sometime in Oct /Nov. must be the demand form all the British bikes!

I'm getting one from Holland Norton Works.

Hi Antony,

You might consider routing your breather pipe into a catch tank of some description. Much of what comes through this pipe is contaminated with water from the condensation that builds up as the crankcases cool after use. This manifests itself as white creamy mayonaisse in the top of the filler neck.

On my recently rebult 750, My oil tank vents into a HP sauce bottle and collects nil so far, My XS650 breather from the back of the timing cover breaths into a small vented drinks bottle beneath the carbs. This picks up little when tooling around at traffic speed, but en-route to the national rally (240 miles) at motorway speed it collected about 100cc each way. I think this is partially caused by oil flung off the timing chain ending up in the vicinity of the vent pipe. The next time the timing cover comes off I will fit a baffle to prevent this. The Mayonaisse is a thing of the past for me now.