[2015 Z Force 800 53/Trail EPS]

Yeah the compression seems good and the amount of blow-by needed to send oil to the airbox would be..IMO..impossible by leaking valve seals and guides alone unless one other situation exists that I'll talk about in a moment. They need to do a leak-down test to find where this leakage is coming from and confirm that the valve or baffle that is on the vent port is functioning correctly.

Now for that other thought. In my testing of my exhaust system before doing the modification I did I found that the system under hard acceleration will hold up to 4.3psi. I almost fell off my chair when I saw that as I was used to seeing ounces not pound on exhausts. When I took out the tail piece...the spark arrester.. that pressure was cut to 2.6psi. This is why I did my mod but..having that kind of pressure on the exhaust valve guides will force hotter gasses up the stems and take out the seals a lot faster then with low or what we would consider "normal" exhaust pressures. And if by chance that spark arrester gets partly blocked with carbon deposits, that pressure would be even higher. I suggest you..not the dealer, take the three retainer screws out of the arrester and remove it (cleaning it with a soft wire brush while out). Then test to see if there is any reduction in blow-by. If so..you...and the dealer.. have your answer. It will be too late for the guides and seals but at least it's not major.

I just noticed a bit of oil in the air box as well.  Not sure this is anything to be concerned about, but thought I'd throw it out there.  There was a about a 1/4" in the little clear tube on the bottom. 

Now this leads me to my other question.  I check my oil level and someone on here indicated to not screw the dipstick in to check the level.  My manual reads "insert the dipstick completely into the oil filler hole.." but doesn't say to screw it in.  Is is common knowledge that we are just supposed to place it in the oil filler hole to check the oil level?  My oil level is at the very top, if not a hair over.  Possibly too full causing this issue?

[2015 Z Force 800 53/Trail EPS]

I just noticed a bit of oil in the air box as well.  Not sure this is anything to be concerned about, but thought I'd throw it out there.  There was a about a 1/4" in the little clear tube on the bottom. 

Now this leads me to my other question.  I check my oil level and someone on here indicated to not screw the dipstick in to check the level.  My manual reads "insert the dipstick completely into the oil filler hole.." but doesn't say to screw it in.  Is is common knowledge that we are just supposed to place it in the oil filler hole to check the oil level?  My oil level is at the very top, if not a hair over.  Possibly too full causing this issue?

Really not enough to worry about but just as a reference, mine was doing that just about a third as much and quit completely when I changed my intake system...so..at least check your prefilter bag that's over the intake tube. Any vacuum on the box at higher RPMs will pull more on the crankcase. And just a side note, my shop manual says not to screw the dip stick in when checking..I believe.. but the owners manual says insert it fully so I go by the shop manual...and mine has been over full sense the last change..like 1/8" over the max line now for almost 500 miles...and no sign of oil in the box...at least none on last check a couple-hundred miles ago.

Here's from the service manual.

Well, my air filter was dirty, and ready for a good cleaning.  Maybe that prompted it.  It did just happen recently, and I'll do some higher speed driving here and there.  I'll clean it all out really well and keep an eye on it. 

[2015 Z Force 800 53/Trail EPS]

Well, my air filter was dirty, and ready for a good cleaning.  Maybe that prompted it.  It did just happen recently, and I'll do some higher speed driving here and there.  I'll clean it all out really well and keep an eye on it. 

Be sure to clean that prefilter. That's the one that will put vacuum on the box when dirty.

Well, my air filter was dirty, and ready for a good cleaning.  Maybe that prompted it.  It did just happen recently, and I'll do some higher speed driving here and there.  I'll clean it all out really well and keep an eye on it. 

Be sure to clean that prefilter. That's the one that will put vacuum on the box when dirty.

I did clean that one, but that outerwear really wasn't that bad.

[2015 Z Force 800 53/Trail EPS]

Well, my air filter was dirty, and ready for a good cleaning.  Maybe that prompted it.  It did just happen recently, and I'll do some higher speed driving here and there.  I'll clean it all out really well and keep an eye on it. 

Be sure to clean that prefilter. That's the one that will put vacuum on the box when dirty.

I did clean that one, but that outerwear really wasn't that bad.

We are talking about the one over the intake tube, under the cover in the cab..right?

Yessir. The little outerwear.

[2015 Z Force 800 53/Trail EPS]

Yessir. The little outerwear.

Cool.