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I am preparing to install the SE Extreme Air Cleaner Circle on my 2025 SGU 117 Ci.
After removing the stock Hot Box I noticed no head breather bolts. I found a hose hooked to the aft side that appears to run from the top of the transmission cover.
It seems that HD Company did us a favor here . I can just reroute this hose down somewhere and put a filter on the end.
Then just plug the hole in new body and no hot oily oil filled vapor.
Has anyone else done this? Or maybe something similar? Seems awful easy.
Some stock pictures. The hose that brings the hot oily air. Inside of the hot box. Exterior side where hose hooks up.
[img alt="Hole where vapor enters box.
"]https://cimg0.ibsrv.net/gimg/www.hdforums.com-vbulletin/750x1334/img_3939_72f1398c3de1e5644534247ddf7a585c3f368b23. png[/img] Hole where vapor enters box.
I am preparing to install the SE Extreme Air Cleaner Circle on my 2025 SGU 117 Ci.
After removing the stock Hot Box I noticed no head breather bolts. I found a hose hooked to the aft side that appears to run from the top of the transmission cover.
It seems that HD Company did us a favor here . I can just reroute this hose down somewhere and put a filter on the end.
Then just plug the hole in new body and no hot oily oil filled vapor.
Has anyone else done this? Or maybe something similar? Seems awful easy.
Some stock pictures. The hose that brings the hot oily air. Inside of the hot box. Exterior side where hose hooks up.
[img alt="Hole where vapor enters box.
"]https://cimg0.ibsrv.net/gimg/www.hdforums.com-vbulletin/750x1334/img_3939_72f1398c3de1e5644534247ddf7a585c3f368b23. png[/img] Hole where vapor enters box.
Thanks for the comments.
Mike
I installed the same AC on my 25 RG, left it TF alone..no need to fuss, fret or worry about trying to modify or improve its design and functionality....just go ride and have fun
I wouldn't worry about the crankcase vapors. The new system has baffles in the transmission top piece in addition to the length and vertical path of the hose should significantly reduce oil residue entering the throttle body.
I know people do rerouting, me, I didn't bother - the new oil/air separator in the transmission cover does a good job. On my 5k service, when I took air cleaner for washing (I have extreme wedge) the intake was bone dry.
The stock OE black hose that carrys hot dirty oil to the Intake reroutes very easily to R!H side just behind the dipstick.
When I first removed the OE hot box i found 3 to 4 drops of oil on the intake only. This was after only a fifteen mile ride from the dealership after a 1000 mile service. I think with the engine running it will draw more vapor than one realizes!
After finding the correct fine threaded plug it was very simple to plug this hole in the new breather plate, stopping every bit of hot oily air from going in the bikes combustion chamber.
Now only a fuel and air mixture enters the intake like it should be.
I will keep an eye on the hose if it makes a mess or not. I saw a little chrome filter at my local car shop for $6 bucks that I could install on the end.
Ride safe and hot oily air
.
Last edited by MikeSGU; Jan 8, 2026 at 10:02 AM.
Reason: Picture not working
The stock OE black hose that carry’s hot dirty oil to the Intake reroutes very easily to R!H side just behind the dipstick.
When I first removed the OE hot box i found 3 to 4 drops of oil on the intake only. This was after only a fifteen mile ride from the dealership after a 1000 mile service. I think with the engine running it will draw more vapor than one realizes!
After finding the correct fine threaded plug it was very simple to plug this hole in the new breather plate, stopping every bit of hot oily air from going in the bikes combustion chamber.
Now only a fuel and air mixture enters the intake like it should be.
I will keep an eye on the hose if it makes a mess or not. I saw a little chrome filter at my local car shop for $6 bucks that I could install on the end.
Ride safe and hot oily air free!
well you did ask in the title if rerouting is or isn't necessary..all the responses are in agreement it's not on these new model redesigns..it really is much ado about nothing but some people just can't help but tinker with stuff, but it's your bike and you are concerned about it so commence tinkering..I'm sticking with tinker less, ride more
edit: worth noting that after 28,000 miles on my 2024 and 9000 miles on my 2025, each time I have swapped out air filters for clean ones, the inside of the AC, TB, etc. looked spotless, as if it just rolled off the assembly line..I could never have said that about any of my previous TC or M8 MY bikes.
RE: "When I first removed the OE hot box i found 3 to 4 drops of oil on the intake only. This was after only a fifteen mile ride from the dealership after a 1000 mile service. I think with the engine running it will draw more vapor than one realizes!" .. I have always been in the habit of no short rides due to not getting hot enough, especially in colder months...the Owners Manual even says that frequent 15 miles or less rides in less than 60 degree F temps one should change their oil every 1500 miles..so yeah, Ride Hard and Put Away..DRY !
well you did ask in the title if rerouting is or isn't necessary..all the responses are in agreement it's not on these new model redesigns..it really is much ado about nothing but some people just can't help but tinker with stuff, but it's your bike and you are concerned about it so commence tinkering..I'm sticking with tinker less, ride more
edit: worth noting that after 28,000 miles on my 2024 and 9000 miles on my 2025, each time I have swapped out air filters for clean ones, the inside of the AC, TB, etc. looked spotless, as if it just rolled off the assembly line..I could never have said that about any of my previous TC or M8 MY bikes.
RE: "When I first removed the OE hot box i found 3 to 4 drops of oil on the intake only. This was after only a fifteen mile ride from the dealership after a 1000 mile service. I think with the engine running it will draw more vapor than one realizes!" .. I have always been in the habit of no short rides due to not getting hot enough, especially in colder months...the Owners Manual even says that frequent 15 miles or less rides in less than 60 degree F temps one should change their oil every 1500 miles..so yeah, Ride Hard and Put Away..DRY !
@mjwebb No worries on the comments of another view! As a matter of fact I like to hear all different views. One can make better decisions that way.
On my 2024 114 CI I did have to buy or make my own EBS kit. 24 114 ci
I drilled a hole 10 thousands smaller in the back plate to get a tight fit on the hose so it wouldnt leak.
On the 2025 117 CI due to HDs new design no kit is needed, and no need to buy any hose either. Just a small plug period. Which I did NOT know at the beginning of this project, hence the tittle.
My trip home from dealer was straight home due to my wife having foot surgery two days prior and I needed to be there for her. The temperature that day was 68 degrees F and it was hard to go straight home. The bike did warm up to 205 degrees F.
Before I usually ride we go about 8 miles to the gas station that sells non-ethanol premium. So it is unpractical for me to worry about miles before warm up.
Anyway thanks to all for all the comments and I assure you they are appreciated.
Really to old to tinker but I want my bike to last a long time and run fantastic . I hope someone will see this and realize thats its very easy to stop ALL fumes going into the intake!
@mjwebb On my 2024 114 CI I did have to buy or make my own EBS kit.
I learned on my 2020 RGS 114 which I left 100% bone stock...they broke a spark plug off when changing them while in getting serviced at 50,000 miles..had to remove the head which was replaced under warranty..I went and took a picture of the piston, which barely had any carbon on it whatsoever..I ran it for another 25,000 miles and when I traded it in at 75,000 the entire bike was 100% trouble free, never even had a small issue of any kind..regarding the breather system, it left me with the impression that if one runs their engine hard often, which I always have, carbon just isn't an issue..I always ran top tier premium unleaded, and SYN 3 engine oil in that bike, not that that mattered... . My wife rarely ran her 107 over 3000 rpms and at 20,000 miles was puking oil thru the breathers and had so much carbon build up they replaced the heads, under warranty thankfully...but old school blow the carbon out, Italian tune up or whatever, is what is most important as far as I am concerned, based on our personal experience anyway
I learned on my 2020 RGS 114 which I left 100% bone stock...they broke a spark plug off when changing them while in getting serviced at 50,000 miles..had to remove the head which was replaced under warranty..I went and took a picture of the piston, which barely had any carbon on it whatsoever..I ran it for another 25,000 miles and when I traded it in at 75,000 the entire bike was 100% trouble free, never even had a small issue of any kind..regarding the breather system, it left me with the impression that if one runs their engine hard often, which I always have, carbon just isn't an issue..I always ran top tier premium unleaded, and SYN 3 engine oil in that bike, not that that mattered... . My wife rarely ran her 107 over 3000 rpms and at 20,000 miles was puking oil thru the breathers and had so much carbon build up they replaced the heads, under warranty thankfully...but old school blow the carbon out, Italian tune up or whatever, is what is most important as far as I am concerned, based on our personal experience anyway
Yes I think actually riding spirited lets say helps. My 2015 Limited occasionally spewed oily crap coming out of the SE filter, and it was stage 2 with a TTS tune.
Dont remember on my 2008 SG Anniversary.
The new 117 CI motor sure is nice and has quite a few upgrades for sure!
Bike runs even better (seat of pants dyno) with the new A/C on it. Bike hits triple digits really fast. Took just a 10 mile test ride without momma.
Cheers,
Mike
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117 CI EBS not needed?
