COMPARE M8 CRANKCASE VENTING - A1 Cycle, Trask, Feuling - Kevin Baxter - Pro Twin Performance 

I'm running the Trask check M8 trans cover vented to my external breather system for the heads with a Y and everything goes into a DK Customs catch can. After installing the Trask trans cover basically zero oil comes from either vent and the catch can is always empty; this combination works awesome!

My motorcycle has the best ventilation system already engineered into it on my F117 fighter by combat motors

I have a 2018 CVO with a 117ci…..no sumping issues…..so not doing anything.

I would just like to add a note on the vented dip stick vs vented trans top plate on M8 softails. I recently finished installing a 128ci big bore kit bought from you by the way) on my '19 Breakout. I initially added a Feuling vented dip stick but had to remove it because it never would stop discharging liquid out the filter (enough that it was leaving an oil spot and contaminating my rear tire. After removing the Feuling dipstick I installed the Trask top cover and have not had any issues with it at all. I was surprised by this because I've been running a Feuling dipstick on my '19 Road King for some time without any problems. I don't know if the Softails have different configuration on their oil return system or if it was caused by the added displacement, but thought it was something worth mentioning here.

Great information as usual, I purchased a Fueling vented dip stick a couple years ago so I am glad it didn’t turn out to be a waste of money.. 😊

Several questions regarding this subject still remain, even after this video, which I appreciate your time and effort in creating. But what I have yet to find, does performing a breather mod, where it is vented either to the atmosphere or to a catch can, hurt engine performance in any way since you a removing a source of vacuum.? I have read articles and watched videos that state that having vacuum in the engine helps pull oil down the cylinder walls to avoid excess blowby. Some say the size of a Harley motor doesn't create enough vacuum to have an effect. But then there are companies like trask and fueling putting in check valves in to let air out but not suck any in, and others like the a1 and dk customs external breather solutions that are wide open

Awesome delivery , and well worded ! Thanks for these videos . As a “ senior citizen “ and having been owning old school Harleys from the 1970’s ( 13 so far ) from a 53 pan head to my now new FXLR 2018 Low Rider , I have been searching for a channel like yours for a long time . Appreciate you sharing your expertise , sir !

I went and got the Feuling vented dipstick and it has reduced how much oil ends up inside the intake by half. The only real con about the Feuling is the set screw for the cap should have been a standard size Allen screw because the one Feuling used is way smaller than any Allen wrench I have in my collection. My question is, would it be harmful to my M8 if I added the vented trans cover to work in tandem with the vented dipstick?

Thanks for the videos Kevin. I’m running the A1 dip stick on my 2018 107 with a stage 2 Harley toque cam so far no issues. I did put the catch can under the side cover to protect it from sucking in rain water. I only have about 5000 miles on the dip stick but I think it is helping the oil consumption which Harley says is exceptable.

Gday fellow enthusiasts Have fitted fueling dipstick and Trask top cover on 2020 deluxe Money well spent All good from Australia

2019 Road Glide with state 2. I installed a complete S&S cam chest. I vented the crank with Fueling vented dipstick and vented the primary with Harley’s own primary vent tube. I ran the bike hard from Chicago to Savannah GA and back on vacation. Zero oil sumping Zero oil in my throttle body Zero oil consumption! That’s running high rpm both ways. I’m happy to say I have a tight 107 motor and should probably leave it alone now. So, if your motor is relatively unmodified and still sumps oil or blows excessive into your throttle body you might have issues going on. Make sure your pre 2000 M8 has an updated oil pump and also a place to check is your piston oilers which require removing your cylinders. They could be loose or defective causing excessive oil to dump into your crankcase. Mine were loose from the factory. Yes, I also removed my jugs to check them and also to install better head gaskets with cometic multilayer steel slightly thinner to raise compression. Top everything off with S&S head bolts and rocker shaft studs. Basically replacing most of the weak links that came out of a stock Harley motor.

Running The Fueling dipstick. Zero issues

Kevin do you think even the new 22+ m8s suffer/need the crank case vented? Or even the transmissions? I was told that the 22 fxlrs I have, has a trans vent.

Kevin I loved this Video. I bought a new 21 Tri Glide and added a Catch can and purchased a throttle body vent from DK customs. I know many companies make great aftermarket parts for HD, just wanted to add DK customs to the mix. All these you mentioned I have purchased from and find all to engineer great products. Thanks for the education on crankcase pressure. Papa.

True that concerning the water/oil mixture via catch can. Installed DKs set up on both my scooters, one TC one M8, very happy with both, but you must remember to dump them out on occasion. Also installed Love jugs on the TC 110. They make significant difference in engine temp, although they do make rider and pass, right leg HOT… the price we pay for longevity.

Speaking of external breathers, and catch cans: do you think having the breather hose from each cylinder separate to its on catch can would be best or is 2 into 1 ok? I have a 2 in 1 hose set up, and I’m barely seeing any residue in the catch can, and I’m wondering if they are working against each other to prevent the external breather from working as it should.

I have a 2020 Triglide with about 8,000 miles on it. At the suggestion of a well respected builder here in Wi., I plan to leave it bone stock. At least in terms of any engine modifications. I have been giving thought to some sort of vent, mostly to keep oil mist from going into the combustion chamber. I have been checking the air filter for oil contamination and there is virtually none! However if I start to see any I will be looking into a vent that eliminates the breather tubes going into the throttle body. Love your videos!

What about running both dip stick and trans cover 🤔

Great information! Am running the A1 on my 17 Road King with 0 issues. Would be very interesting to know if there is a meaningful amount of cooling associated with not using a check valve.

Hello Kevin and thank you for another excellent video; much appreciated! Can one "over ventilate" a Harley air/oil cooled V-Twin (2021 M8 114 Touring w/Stage-2 in my case; perfectly maintained and no known or observed issues)? That is, if already running either a Vented Oil Dip (Fueling) Stick or the Transmission Top Cover (Trask), and then add a Filter or Catch Can to the head breather bolts (& air cleaner that does not allow feeding/venting back into the air cleaner/throttle body), would or could this ventilation [by both means] be unnecessary or excessive?

Lol back in 1995 build a 131 cubic inch evo lol, way before a lot of people and there a lot of bullshit products out there ,you got a 100 lbs of shit in a 5 lb bag! there not enough crankcase volume to displace the negative pressure. Bottom line & there never will be lol

Hi Kevin, Thanks for all the great videos. I have a 2018 Street Glide with the M8 107. I was hoping to get your opinion. I've been watching a bunch of videos about oil blowby and ways to avoid it. The vented dip sticks, trans covers, and rerouting head breathers to a catch can. I tried the A1 vented dip stick and ended up with oil all over the place. I saw another youtuber ( ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bIyaV8KP8HI.html ) vent the crankcase through the transmission vent and reroute the breathers to the top of trans cover, letting the blowby oil drain back to crankcase. That sounded good, not having to maintain a catch can, but it still doesn't allow for vacuum in the crankcase, and connecting the crankcase to the transmission did seem like a good idea either. What do you think about putting two fittings in the transmission cover over the crankcase. Rerouting the head breathers together and tee off to one of the fittings, and put manifold vacuum to the other fitting. Would that provide the vacuum needed for the rings to seal and keep the blowby oil mist out of the combustion chamber? I appreciate your thoughts and opinions. Thanks again for your time.

I have a 19 RGS,installed an S&S 475C cam chest kit with plate and pump.I also installed an A1 ventilator but I put a cheap Amazon check valve in the vent hose to maintain crankcase vacuum.

Hey Kevin, great video, I recently installed (2), yes two catch cans on my 16 Twin Cam Road Glide, one on each cylinder. The bike had 30,000 miles on it when I bought it, and runs well, but I wanted to see if I installed the catch cans, what color or how dirty of blow-by I would find, as we generally are guessing how a motor has been treated by the previous owner when buying a used bike with more than a few miles on it. So far I have found only clean colored condensation from each cylinder, so I think I picked a solid bike for the most part that was well taken care of internally. The reason for my comment today, is not only to endorse your video here, and the reasoning, but also feel the twin catch can system is a great way to monitor the blow by as the bikes mileage and age increases, while not the only indicator of an internal problem that is growing, a very easy way for the DIY guys to monitor the engine internals, and head off a problem timely, before it gets to the “big problem” stage. You do a great job, your a great teacher, and have a well thought out presentation, that keeps your viewers coming back I would bet, I know I do, I only wish I had more time to consume all that your videos offer. Thanks for all you give to the bike community, your channel certainly fills a void, and would be missed if it was not there. Blue Skies!

Late to the game.... but 2024 HDs (117/121) now have different vent routing from the factory and one off the top of trans/oil cover. Sorry Trask😉🤠✌️

Interview for Harley owners? How do you feel after purchasing a HD for $30,000 or more only only to begin noticing it start to use oil and need engine work with as little as 50k (or much less) on the odometer?

running external hoses to a tee then bottom of frame. no issues

Great video. I vented my 88TC breather bolts to atmosphere. Not sure what I’ll do with my 23 Street Glide ST. I’ll try to vent that the same way, but I need to look at it when it shows up

I’m running the Trask top cover. Would there be any advantage to adding either dipstick? If the A1 dipstick could actually lower engine temp I would consider it. My bike runs hot, hotter than I think it should.

Running A1 oil cap. Venting heads to a catch can. $100, cheap insurance.

Great video. Just a thought, could the trans cover be vented to the throttle body vacuum port with a vacuum valve, post butterfly seeing as the trans cover does not really have any oil mist. My thoughts are keeping more vacuum on the crank case. Am I going down the wrong road with this thought? I am basing this on a standard car PCV system but no oil mist because the trans port is up high. Thanks.

I run about a quart and a half of oil in my bike. Never had problems with excess oil coming out.

Great video and i greatly appreciate your time and expertise. would the feuling dipstick not be rendered ineffective under hard acceleration? With the trans cover that much higher on the cases, would that not be optimal?

Hi Kevin, I have a 2022 Road Glide which comes with a Vented Trans Cover out the factory, does that mean I don't need any of the 4 products you've mentioned in the video? Looking to go as far as just a Stage 2 cam

Did a homemade version of the Trask..... bulkhead fitting, check valve, out to a filter. Checked my throttle body several times and virtually no oil.

Would it help a 20l8 H.D Breakout 114ci with less than 10,000 miles ?

I’m wondering if there are certain years that this is an issue with? I installed it on my 2017 and it smoothed the motor right out and I picked up 2 mPG. Did HD fix the issue in later models or are they still unvented? Thanks for your time.

What is your opinion about possibly sucking air without a check valve? Is there any possible negative side effects?

Hi Kevin I’m Robert love the videos you have helped so many people understand the science with these bikes I have a 2017 ultra limited 107 im running my tran top cover to vacuum ported catch can with baffle straight to intake port on back side of intake manifold with damper and vacuum gauge vacuum is 5 pounds I’m letting breather bolts breath in to catch can and stock oil pump cause with vacuum no aeration in oil and no pressure build up so oil pump will work better .better seal on piston rings and both vacuum/pressure release are serving a purpose in preventing blow by I think a awesome problem solver. Kevin do you think this is a good idea and how much vacuum do you think is best

Great video man. I have all my parts together for a SS stage 2 with the 475 cam chest kit. I bought the fueling vented dipstick. I guess if I have a problem with that I'll go with the Trask set up.

Thanks Kevin! Zero oil carry over so far at 22k miles on my M8.

Im using moroso catch can Seems to work great It catches quite a bit of crap in it! Empty it about every 1500 miles.

AWESOME! You set me straight on the venting from the heads. I WAS gonna get the Trask cover and vent the heads right into that via a Tee fitting, After listening to you, I'll stick with the catch can!! Thanks a bunch!

With my m8 107 buildup. 129 now. I installed a vented dipstick. I mounted the breather filter on top of the dipstick directly. NOT GOOD!!! Had blowby misting oil getting on the saddle bags. I ran a 3/8 rubber line after the misting on the bike issue to the top of the motor to rest on tip of the intake manifold with the breather filter installed at the end. I have 100 miles on the new performance build. So of course the rings haven't seated yet. Naturally there will be more blow by. Added....I was in 3rd gear at 55mph getting onto the freeway. I pulled 2/3 throttle went up to 65 mph and my rear tire broke loose!!! Scary, but cool!!! Weather was dry, road also. I'm assuming some misted oil got onto the rear tire. I haven't dyno tuned the bike yet. The thundermax is still learning the build up. I created a monster!!!!

KEVIN: I've asked this question on a previous video but was never answered so this is a good place to ask again. On that previous video you explained how some crankcase preasure is helpful in keeping the piston rings, particularly the second or middle ring I think, expanded and sealing properly. Would these vents eliminate most or all of that preasure creating another issue? Thanks FWS

Kevin, I talked with another M8 Harley owner who switched his factory air filter with an S&S Stealth air filter kit. I was tired of seeing oil splatter on the front of my left side bag as well as fouling up the cylinders, so I bought one & installed it on my bike. That seemed to have stopped that problem.

I have the Trask Check m8 in my 128 build and seems to be working well. Great video as always Kevin 🙌👏

Thanks Kevin great info as always. Does the A1 dipstick come with tube and filter or is just vented in the air?

I have a 2020 114 Heritage. Got bad sumping after 19k miles, yes even with the improved 2020 pump.. When new I put on the fueling dipstick and DKCustoms head breather both venting with filters. Always got drops of oil coming out of both filters during moderate to hard rides. After the sumping issue I replaced the 2020 pump with An S&S oil pump and cam plate along with a new sump plug. Bike is running fine and no sumping so far however I continue to get the same amount of oil seeping from both filters. Could there still be a problem or is this normal?

Hey Kevin. How does venting the trans, vent the crank case? Are m8's that different?

Hi Kevin. What about the Air Cleaner ventilation systems?? DK Customs make a nice kit with a non re-circulating catch can. Some people make their own kit with some hose, clamps and a t-piece.

Really enjoy your videos, though mates reckon am somewhat geeky as enjoy technical videos. The vast majority of harley owners do not have the technical ability or confidence to vent the head breathers, particularly in the UK though no less in the USA either where ignorance is bliss. Many due to high moisture levels in our cold wet atmosphere have startup issues, cut out issues and high revs coming down gears clutch pulled after a good thrash. Trying to explain that moisture and oil vapour makes a creamy goop that is occassionaly hitting the IAT sensor in the fuel tract and causing the bike to hiccup. That harley will clean all the goop out of the path from head breathers to throttle body and that it will then take a few months to re-create the path to the problem all over again falls on deaf ears. I never had the issue on my first harley but definitely had it on my second, possibly because its less cold and wet well south of Scotland where my second harley came from. Looking to get a 2022 Low Rider S used with as low mileage as possible and vent both the crankcase and head beathers from the get go. Not too later fit the SS cam plate and performance oil pump plus lifters with billet collars. Later fit the Darkhose Crankworks Compensator as a cushed comp definitely seems a better proposition than what harley have been using for decades. I just hope I aint got any swarf left in my crankcase from assembly : O From extensive online reasearch crankcase top vents are far superior to what is effectively a poor catch can on a dipstick, these seem like a very messy option.

Kevin, another great video! Does the vented dipstick allow for a smoother revving motor? 15:37

I have a Stage 4 on my 2018 Street Glide, I installed the Feuling dip stick, it helped a little but at 80mpr I still have oil on my right bag, oil in the breather, my next thought is to do the $12.00 fix and vent it back into the transmission cover in the first port that goes back into the engine, I have the 1 breather can from the vented dip stick and always smell oil, so not happy with that

The information you share with your viewers is mind blowing!!! Thank you for such detail!!!!

Probably a foolish question, but having vented the crankcase through the transmission cover (ala Trask M8) is there any need to continue venting through the intake breather bolts? I don't know how to measure the volume of pressure to insure the transmission vent is sufficient and I don't want to blow seals or gaskets. It sure would solve the oil in my air cleaner if I could simply install solid bolts in the breathers.

Why not just cut a notch in the web under the trans cover and vent through the same vent as the transmission?

Long story short Harley built a pile of shit (again) and it's up to consumers to choose better motorcycles from this century

Check this out .sorry kevin , im trying to put you a picture of my piston top covered in baked on oil.

Mr Baxter, I have been looking in to the same products that you just did your video on. First some background on me. I'm just a humble Tech that works on Victory, Triumphs and Indian motorcycles. "Polaris" Indian and new Triumphs to be clear. I have done a few Top ends on Indians and have seen the carbon buildup on low mile engines from burning oil. So when I got my new 22 Road Glide I want to prevent what I have seen in a lot of big displacement engines and that is oil in the intake. In the research I have done the breathers that have a one way valve act like a PCV valve on a car. Vents the positive psi but keeps the vacuum in the crank case to help the rings seal and reduce "blow by". That is what I have found.

Are you in need of a Panhead 65 motor for your show? It would take me a week to get her out of the box and 2 days to build a shipping container. And I will pay for any parts. She's not for sale though. You would have to send her back home. She's in good running condition.

Always educational! Thanks for the knowledge Kevin.

Hmmmm, shoulda been done by HD. Now gotta spend extra to get the thing to run right?

From Kevin Hill : I did meet you b.w.w. in Colorado wanting to vent rear cylinder valve cover on hondavtx1300 isn't a bad idea toasting you k.h.

I use the fueling dip stick 114 with a red shift cam this system works great np crap in the catch can making 134 hp and 142 tork great runner

Awsome vid nice Procharger box in the back someone is gona get MORE POWER for sure

Please ,panhead rebuild first see what I have been doing wrong for 45 years

Why hasn’t HD introduced a fix for the venting issue so we don’t have to?

As always thanks for all the information! Much appreciated

Hello Kevin! You mentioned once before that the EVO's had thicker rings then the M,8's. When doing a big bore kit. Do they use thicker rings for M 8's? You also mentioned loosing crank case vacuum by venting breather to atmosphere. Is it possible to use the capped vacuum nipple on top of the EFI back into the crank case to reclaim manifold vacuum?

Another much needed straight forward video. Thanks

So I have done the trask top cover and external intake breather on my 18 RG also have pulled the plug in the bottom of the engine and all I got was a couple drops of oil so I don't believe it's sumping but yet I'm getting not just a oil mist but actually oil from head breathers should do you think I should check the breather valves in the rocker box or you think something else is wrong?

Too bad the discount code for A1 doesn't work anymore.

Another great video Kevin thank you so much. 🙏🙏

Love your videos Kevin. I throw your name out there every time I run across questions about where to find a engine builder. Keep up the awesome work!!

Hey, really well delivered lecture on Venting, however I noticed you didnt side on the check valve/vacuum debate, and I suspect the A1 cycle tran plate does not have a reed or a check valve either.. Now my opinion of the Trask..not olny does it (and the Fueling design) vent the crankcase, but are designed to help maintain some level of vacuum that might be present at times. I think its the better unit..except for the under side screws to access the Reeds,.. They can and if they fall out, there can be issues which can cause engine damage.. Trash should have put that access on top of the plate! So I just made my own crankcase vent with check valve system for about $30

Another good video Kevin thanks ! I do have a request though not sure if you have a video on head bearings I'm replacing my 99 road king front suspension with ledgend set up but want to do the bearings the bike has 52k and I'm hearing a clunk when I hit a big bump but the only thing I worry about is setting the bearing free play I of course have a manual and watched some videos but not good videos I can trust would love to see you do one. thanks for all the great information you share with us !!

thankyou Kevin A1 all the way.

Hey Kevin, Doesn't the addition of the oil pumps with the seal virtually eliminate the sumping and the need for added venting?

you can do both of them yourself for like 10$ for the intake and 0 $ for the dipstick or trans case... well they will cost you a one way valve price and in the dipstick a pice of screen and a couple cotton balls.

Do you need any of this systems in a Twin Cam engine? (2011 TC96B)

Thank you for the free education

I have two questions for you Kevin excuse my ignorance in the subject but could carbon deposit be removed to some degree by the old fashioned water injection system to the intake or would this only pertain to carb. equipped engines vs injection. Next question is could one use the Venturi effect by tapping into the exhaust outby the catalytic section (if any are present) in the exhaust? Love your videos.

I run the Feuling vented dipstick. I actually could tell a difference in the higher RPM's. I installed on a new FLTRXS as preventative measure.

Kevin great video. I have an external breather kit along with a catch can and a vented dipstick from A-1 cycles. I have no issues whatsoever and have peace of mind.

Always great info given in a clear and well-explained format! Thank you, Sir! 👍

Just bought the a1 cycles dipstick after watching this and you discount code saved me 15.00, thanks.

Excellent advice that I am working on, thanks.

Wipe it with a rag big dog..!!!!!….it’s a Harley….

👍🏻🇨🇦

Hi Kevin, thanks for this great video again! I've got a TC 88 from 2000 and I built a catch can for myself. I used a 2 inch 1/4 inch hose to get the oil and the dirt out and into the DIY catch can. This works fine. I had a look into the cylinder head with an endoscope camera. The motor has got 25.000 miles now and I saw a medium carbon layer on the pistons. I wonder if this carbon layer will disappear without a cleaner time after time or if I should use a special cleaner to get it away from the pistons? I' ve bought a special cleaner which can be used without disassembling the motor but I wonder if it is really necessary to use this cleaner or if the motor cleans itself after riding several hundred miles? I am curious about your answer! Thanks in advance! Boneskaker from Germany

Thanks for another great video on this topic. It really helps to comprehensively understand the issue.

I cannot seem to find the A1 cycle vented trans top cover. Can you guide me in the right direction to find it?

I have a 2020 SGS with a stage 2. I also installed a feuling oil pump, camplate and lifters with an after market air intake and a mid length Bassani 2 in 1 mid length exhaust . The bike is tuned with Harleys SE tuner. I installed the Feuling vented dipstick (Did not run the tubing) at about 3000 miles. I currently have 9000 miles and I have seen very little oil blow-by. So my questions are 1. With an M8 that is not really built do I still need this and 2. Does little to no blow-by mean the pistons are fine ?

Thanks for the info

My 19 road King sumped the transmission fluid into the primary. I vented the primary and solved the problem.

Always enjoy these discussions and learning. I like to build/rebuild Harleys but my frequency is maybe 1 engine every few years so….. I lean on the pros. Thank you.

Enjoyed this informational video. Thanks

I am looking forward to the panhandle!

Great information and understandable. Kevin you da man