Does anyone know what the o.d. of the air inlet is on the air filter box ?
Thanks fellas.

[2015 Z Force 800 53/Trail EPS]

Does anyone know what the o.d. of the air inlet is on the air filter box ?
Thanks fellas.

Well, it's metric but when I first installed my new plumbing, I used 2.5" turbo intake aluminum off the boot and it fit perfect. Also later I redirected it and used a silicone 2.5"  45 off of the port and that also fit fine....so..2.5" for the Z's box intake port.

Once again to the rescue. thank you
Nmk.

[2015 Z Force 800 53/Trail EPS]

Welcome...lol 


What I always found odd was that at the top of the OE intake pipe where it turns toward the opening it chokes-down to about 1.75". Some manufacturers do this for EPA or sound control and to apply some vacuum on the airbox but those that do maintain a slight vacuum from about 2K and up. CFM's don't get that until about 3800 so..it can't be for noise or EPA reasons. It just must be because of the room that had to work with behind the grill. The air cleaner side is about 2.25" so..makes sense to me to go a little bigger on the box intake to kill any hint of vacuum restriction it would make. I have 3" all the way through on the CVT intake and all 3" after that section of 2.5" on the engine air intake. The engine seems to like it fine and with zero vacuum on the box, I get nothing being pulled-up the engine crankcase vent tube..almost not even vapor. I call that a win. 

Excellent reasoning NMK. I intend to try to make a close copy of your engine air intake plumbing for those reasons.
It has baffled me why CF Moto engineers would design and construct a tightly plumbed intake system, only to stop short at the grill and fail to connect grill and plenum but to draw air from the dirty dusty engine compartment through a hole on the BACK side of the plenum!

I can only guess that someone decided that there was an unacceptable amount of hiss and honk heard at the grill when the intake system was intact, and they decided that esthetics should win out over engine life. This unknown party must have decreed to interrupt the grill connection, make the hole instead on the back side of the plenum, and in a lame gesture to address the intake's new exposure to dust, drag an ill fitting nylon stocking style sock over the end.

I hope to be able to route the intake tube so that it doesn't run directly behind that nice flat spot on the low left wall behind the passenger seat. This flat spot looks like a good place to install an access plate like this one, and it looks like with the help of one of those oil dipstick extensions I might be able to actually reach the dipstick from a relatively easy spot with my big monkey mitts.

https://www.amazon.ca/MonkeyJack-4Inch-Marine-Inspection-Access/dp/B076F8BNZF/ref=sr_1_13?ie=UTF8&qid=1518715756&sr=8-13&keywords=deck+plate