2018 Fat Bob Breathers Known Problem
#21
Here are a couple of links to diagrams-
https://partstream.arinet.com/Image?...partfinder.htm
https://shop.outpostalaska.com/oempa...R_-_FLFB,_FLSB,
Either one of these two EBS's will work with that A/C-
http://www.dkcustomproducts.com/twin...-dk-tc-brt.htm
http://www.dkcustomproducts.com/exte...-tc-brt-cc.htm
edited-
I see the links to the diagrams are not working.
if you go to this link and click Harley, and then to the year and model, and then to the air cleaner, you will see a diagram.
https://shop.outpostalaska.com/oempartfinder.htm
https://partstream.arinet.com/Image?...partfinder.htm
https://shop.outpostalaska.com/oempa...R_-_FLFB,_FLSB,
Either one of these two EBS's will work with that A/C-
http://www.dkcustomproducts.com/twin...-dk-tc-brt.htm
http://www.dkcustomproducts.com/exte...-tc-brt-cc.htm
edited-
I see the links to the diagrams are not working.
if you go to this link and click Harley, and then to the year and model, and then to the air cleaner, you will see a diagram.
https://shop.outpostalaska.com/oempartfinder.htm
Thank you for the link. It really helped me to understand what all is in there before actually digging in it. It looks like the house will have to be routed out of the rear of the backplate since there is not really a lip to drill through on the bottom of the backplate. I greatly appreciate the information and help.
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DK Custom (07-18-2018)
#22
I guess I need to go look this up in my Service Manual? I was led to believe that the new breathers on the 18's are now vented somehow through the tranny? Not sure how and obviously now wondering about accuracy of this statement.
Last edited by Rickr01; 07-18-2018 at 03:04 PM. Reason: accuracy
#23
I'm pretty sure they are still vented via breather bolts in the heads and the breather assemblies are in there as well and is the reason for the oil coming out of my air cleaner since the vents are routed back into the intake.
#24
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Nope, all that crap goes straight into your throttle body, gumming up the sensors. Then it goes into your combustion chambers, reducing power (no oxygen in that hot oily air) and building up deposits. This also changes your compression ratio, so the tune that initially worked well, is not so good after 5-10K miles.
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Kevin
Gear Up & Ride in! DK Custom 4th Annual Open House, June 8th. 🏍️ Click HERE For The Lowdown.
DKCustomProducts.com
#25
I'm not sure what they mean in the last sentence, "Engine crankcases now breath in this area?" Do the gasses go into this hollow sealed area then up to air intake? Anyone have a clarification?
Crankcases for the M-8 are all new, over 20 percent stronger, with a new front engine mount interface and a relocated oil filter mount being the most obvious changes. The crankshaft position sensor is now located on right side case at the bottom of the engine, a move also dictated by the addition of the new balancer. Inside the cases are new shouldered cylinder studs, spaced farther apart and reconfigured to handle the larger cylinders. The changes were made to accommodate the new gear-driven balance that lives in front of the crankshaft. The factory is quite rightfully proud of their investment in the high-tech machinery required to make these cases (not to mention the heads) right down to robotic powder-coating that (pardon the pun) “finishes” the process.
Crankcases for the M-8 are all new, over 20 percent stronger, with a new front engine mount interface and a relocated oil filter mount being the most obvious changes. The crankshaft position sensor is now located on right side case at the bottom of the engine, a move also dictated by the addition of the new balancer. Inside the cases are new shouldered cylinder studs, spaced farther apart and reconfigured to handle the larger cylinders. The changes were made to accommodate the new gear-driven balance that lives in front of the crankshaft. The factory is quite rightfully proud of their investment in the high-tech machinery required to make these cases (not to mention the heads) right down to robotic powder-coating that (pardon the pun) “finishes” the process.
The new-for-2017 interface between engine and transmission cases uses a new metal-backed gasket with beaded surfaces to seal internal passages between oil tank and engine. Makes sense, when you consider the engine now breathes into this area.
Last edited by Rickr01; 07-19-2018 at 09:52 AM.
#26
I'm not sure what they mean in the last sentence, "Engine crankcases now breath in this area?" Do the gasses go into this hollow sealed area then up to air intake? Anyone have a clarification?
Crankcases for the M-8 are all new, over 20 percent stronger, with a new front engine mount interface and a relocated oil filter mount being the most obvious changes. The crankshaft position sensor is now located on right side case at the bottom of the engine, a move also dictated by the addition of the new balancer. Inside the cases are new shouldered cylinder studs, spaced farther apart and reconfigured to handle the larger cylinders. The changes were made to accommodate the new gear-driven balance that lives in front of the crankshaft. The factory is quite rightfully proud of their investment in the high-tech machinery required to make these cases (not to mention the heads) right down to robotic powder-coating that (pardon the pun) “finishes” the process.
Crankcases for the M-8 are all new, over 20 percent stronger, with a new front engine mount interface and a relocated oil filter mount being the most obvious changes. The crankshaft position sensor is now located on right side case at the bottom of the engine, a move also dictated by the addition of the new balancer. Inside the cases are new shouldered cylinder studs, spaced farther apart and reconfigured to handle the larger cylinders. The changes were made to accommodate the new gear-driven balance that lives in front of the crankshaft. The factory is quite rightfully proud of their investment in the high-tech machinery required to make these cases (not to mention the heads) right down to robotic powder-coating that (pardon the pun) “finishes” the process.
The new-for-2017 interface between engine and transmission cases uses a new metal-backed gasket with beaded surfaces to seal internal passages between oil tank and engine. Makes sense, when you consider the engine now breathes into this area.
Last edited by Bowhunter8607; 07-19-2018 at 12:06 PM.
#27
Not sure what they mean in that last sentence either. Maybe they changed how the engine breathes internally but it still vents out of the heads and through the breather screws into the intake and that is why I'm getting the oil out of my air cleaner. From what I understand, which may be incorrect, there is a breather passage from the crank case to the heads where the breather assemblies lie within the rocker boxes. The air that is displaced when the pistons move down flows through the vent passages up to the breather assemblies in the rocker boxes. The breathers allow the air to flow outward through the ports on the right side of the engine. The ports have the breather screws which have the hoses connected to them to route the air into the throttle body and intake to burn up the oily mist instead of venting it to the atmosphere. Not sure if this helps but here are some pics of the breather assembly and the flow of vented air.
#28
#29
During operation displaced crankcase air is vented through the crankshaft roller bearing into the cam compartment. It then travels up the pushrod covers into the rocker boxes. There's an opening in the top of each breather valve. Between a labyrinth, breather element and an umbrella valve only air wth a very very small amount and oil mist should exit the bottom. The air then passes through a small passage in the head and out the breather bolts into the air cleaner. Looks good on paper...in practice not so good.
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Bowhunter8607 (08-06-2018)
#30
Finally got word that the breathers came in late last week. Have it scheduled to go back in on Wednesday to have the updated breathers installed and hopefully be done with the oil dripping out of my air cleaner. The bottom of my air cleaner is now saturated with oil so I am going to ask them to replace it as well under the warranty work they are doing since the bad breathers caused it to become saturated. Hopefully they will. Will also be installing an external breather kit to route the hot nasty air externally instead of back into the engine.
Last edited by Bowhunter8607; 08-06-2018 at 05:29 PM.