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Identifing tube on XS650
- Thread starter AHOTHOMAS0
- Start date
Crankcase breather. Normally hooked up to the stock air boxes you no longer have (Looks like replaced by nylon stockings 
).
).AHOTHOMAS0
XS650 Member
The nylon was temporary lol, I just don't have the filters. The guy before me took em off. Can I just leave this tube open?Crankcase breather. Normally hooked up to the stock air boxes you no longer have (Looks like replaced by nylon stockings
Best to have some sort of filtration on the end.
Air will move in and out of the crankcase as the pistons go up and down. It may suck abrasive dust and other contaminants into the crankcase which is ungood.
It will also "exhale" oil mist and grunge up the bike over time.
If it doesn't run to the airbox, a lot of folks stick a small pleated filter into the end of the hose. Pretty sure if you search around on this board you'll find an example.
Air will move in and out of the crankcase as the pistons go up and down. It may suck abrasive dust and other contaminants into the crankcase which is ungood.
It will also "exhale" oil mist and grunge up the bike over time.
If it doesn't run to the airbox, a lot of folks stick a small pleated filter into the end of the hose. Pretty sure if you search around on this board you'll find an example.
Dude...
You have got some eagle eyes.
I'm constantly amazed at what you guys catch when looking at pics.
hovel
ol' stupid
I've made the mistake of tryin to use panty hose material for an air filter. My experience was that it will not pass enough air for the engine to rpm properly.
I'm confused and still learning. I mistakenly thought the one way valve as 5T has shown before was just to prevent any risk of something going back into the crankcase. It will also have the beneficial effect of reducing crankcase pressure? This is because the crankcase is no longer ingesting air through those vents?Some sort of one way valve on the crankcase vent so the crankcase runs at reduced pressure is a popular modification on these and many other parallel twins.
I'm shocked @5twins didn't mention that.
Ok, so another question, with these check valves installed on the vent tubes, does the crankcase not eventually create a vacuum which could be a bad thing?
Obviously you guys have this sorted; I'm just trying to fully understand it.
Obviously you guys have this sorted; I'm just trying to fully understand it.
I believe that in theory it would create a bit of vacuum in the crankcase. 5T had commented on this in a previous post.
Yes, it's also supposed to create a slight vacuum in the crankcase. This has a few benefits. It's said the motor will produce a bit more power like this although I can't say I've noticed. The bigger benefit I think is a reduced chance of oil leaks (less pressure pressing out on the seals). It may even cure minor leaks for you.
Yahoo! Thanks for the clarification
I am off to the store to buy those check valves you had recommended previously. You'll recall my screw-up from a previous post. I've been running the bike just dumping the hoses into a container, and its been ok, but could be better. Will post results on my own thread.
I am off to the store to buy those check valves you had recommended previously. You'll recall my screw-up from a previous post. I've been running the bike just dumping the hoses into a container, and its been ok, but could be better. Will post results on my own thread.
Some Norton guys did a serious study with sensors and oscilloscopes, and found the vacuum effect decreases as revs increase. So no it won't implode the motor or suck all your oil seals in. Nortons have a smaller crankcase volume (transmission and Primary cases are separate) so the effect is greater and they use reed valves which are prolly more efficient than a ball/spring check valve. ;^)
