View Full Version : Vaccum in crankcase?

01-23-2004, 11:35 PM
This afternoon I removed the oil filler cap to add a snort to the K, and noticed a vaccum in the crankcase.

Granted, I parked it hot, and our weather has turned winter-time cold since I last rode.

I can see where it would be reasonable ... the engine is hot, gases are expanded, and then when it cools, the pressure drops, creating a vaccum inside. But I don't recall ever having such a vaccum in the K100 or the K75.

Is this (vaccum) a normal occurence, or do I need to be nosing around for some type of "issue?"

Thanks in advance,

01-24-2004, 04:38 PM
It's a wonderful thing to have such a tied engine.I would be happy about it.How many miles are on the engine?:)

01-24-2004, 04:58 PM
29,159 ... when I parked it just a few minutes ago.

01-24-2004, 05:28 PM
This makes me wonder if your crankcase breather hose is clogged. Then again I have no experience with these newer models (which based on the mileage I presume you have). I don't know if they have any type of valve, but the early model I had did not, which means that if my old K had a vacuum condition in the case it would equalise through that tube since it's connected to the intake plenum and the pressure flow in from the outside would only be slightly restriced, but certainly not blocked.
Of course you can also look at it this way- if it's holding that vacuum fairly well, then that vacuum isn't finding a place to suck in things that don't belong inside. But do make sure your crankcase venting is functioning properly.

01-24-2004, 06:31 PM

Well, I do know a K will not run properly with the filler cap off the crankcase.

- I don't have any leaks.

- It is not using any more oil than usual (about a half-quart per thousand miles).

Maybe I'm just paranoid.

Which reminds me, I forgot my meds this morning. :boldpurpl


01-25-2004, 12:14 AM
Which reminds me, I forgot my meds this morning.

I must've too when I looked again just now and realised how much stuff I mis-spelled (fixed now).