Crank case Vent Inserts

[Viper]

I rebuilt my engine, and put new parts on.

I took the bike out a number of times, to tune this and that. Today i took it for a quick rip down the country road, and i don't have the breather tubes on the crank case breather vent, and i came back and i was missing a rubber insert which goes inside a metal pipe.

What difference does this make on the bike?

The bike will have airfilters on those vents, just i don't have one of the inserts anymore.

Any info would be appreciated.

 

[5twins]

Those rubber plugs are restrictors. You can run without them but the motor will blow out more oil vapor than usual. You could do what was done on some of the earlier models - cap one pipe off and run only one hose & filter. Or you can swap on the breather from an '80s model. It had only one hose nipple and the end was made smaller. There was no rubber plug, the restriction was cast right in the metal nipple.

 

[Mark Mickley]

Mikes xs sells a breather replacement that keeps a vacuum in the crankcase.

 

[malloym]

I know this experience first hand. I have a 75 and I was missing my restrictor.. actually on my year model one side is blockrf and the other has the insert.. I rode on a 200 mile ride with buddies and I lost 1quart of oil in like 100 miles... with those plugs out the motor will lose a ton of oil...