Originally Posted by mcmann
Next question: would a bike with a waving oil filter (due to WP seal issues) take a bit longer for the oil light to go off at start up . . . To give you a heads up to check the oil filter?
Yes, the oil light will take a little longer than normal to extinguish, and you will have excessive (longer/louder than normal) cam chain rattle at engine start up as well since coolant contaminated oil will take longer to build up pressure and operate the hydraulic cam chain tensioner.
However, if you suspect that a WP might be going, a good check is to pull the clutch cover. Just put the bike on the sidestand and pull the cover, no oil will leak out from there when the bike is on the side stand.
If the inside of the clutch cover looks like this........
WP is shot. The clear clutch cover is really nice for detecting this early. From what I have seen with my bike, this happens way before you get a noticeably wavy oil filter. Although checking coolant level at the radiator will probably detect it even earlier, but its also possible that the WP may not be the cause of the coolant loss. In the picture above, when I pulled my filter, it was not noticeably wavy yet.
Although some folks have a different experience, I have not gotten more than 15,000 miles out of WP yet. Newest shaft version I have used was around the last year or two. I hear the CJ designs shaft holds up quite a bit better, but I have no first hand experience with it.
I wouldn't worry about venting the crankcase into the air box. I have never heard it being an issue on any of the 9X0's so to me it doesnt really make sense to try and fix something that is not broken.
One other thing to note is that many folks tend to overfill the oil, resulting in blow by to the air box. So oil in the airbox possibly may not be due to a bad balance shaft seal. To properly check the oil, dont simply warm up the bike at idle. I'm sure you already know this but, you must go ride it around and get it good and hot to properly check the oil level. Otherwise the reading will be a bit low and folks will tend to over service it.