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Here is my short post on doing a breather modification to eliminate oil into the combustion chamber. I have to say that I am severely disappointed that I need to do this with an RKC engine with just a little under 15k on it. I have owned this bike since new and although i added V&H power duals and slip on mufflers,an Arlen Ness big sucker and a pc 5 tuner, I use this bike to tour and to ride back and forth to work. It is not ridden hard but it is ridden at highway speeds. It has begun to push enough oil into the breather to spit out on the bike and my clothes. I have contemplated performing the feuling cam plate and oil pump but damn, i have a lot of money in this thing already. Anyway, this mod will do for now until i figure out how deep i want to go on this. I love to ride and i bought this bike new. I am running royal purple in it right now and that stuff stinks to high heaven. I haven't ridden since i just completed this mod about an hour ago but hoping some of the odor my dissipate, lol.
I started out my my Arlen Ness Big sucker so I could always go back to stock
Removed ac cover and filter
drilling the ac cover. 21/64 drill or R if you have a complete index
Tapping out hole with 1/8 inch 27 NPT
1/8 inch npt x 1/4 hose barb installed
filled the holes with red rtv as shown on other threads. I had to clean a lot of oil out of the holes!
depth of hose barb
preassembly of hoses before installing ac
preassembly of automotive vent. required modification to get my hose to fit correctly
Finshed(for now) view at engine
filter nestled under frame next to oil pan
2013 RKC with 15 k miles and oil was coming out of the breather
view from curbside rear. will probably go with braided cover or smooth pipe for a cleaner look<br/>
Thanks to all of the people who have posted this mod before. It took me an hour and about 35 dollars plus the tap and drill i had to purchase which took me to 50 bucks including tax. All parts were bought at the auto parts store. 2 packages of 2 foot of 1/4 inch id fuel hose,2 packages of 4 hose clamps, 1 auto breather, 2 hose barbs for fuel system (1/8npt x 1/4),a 1/4" t fitting, plus 21/64 drill and 1/8 npt tap.
Nice write-up. I will be doing mine some day. Started noticing oil on my pants legs, too.
I don't know that RTV is a good product to use in a gasoline environment - epoxy would stick better, longer. But maybe OK for FI motors - not as much gas in the air filter like a carb'd bike.
OK, a little over 100 miles on the bike at highway speeds. No puking evident at the filter under the bike, no noticeable odor. Yes, I am running the oil at the full mark and always have since new. Yes, I understand that the recommendation is the halfway point. However, as i was lying under my bike checking for drips, I began to wonder if the vacuum created inside the throttle body would cause enough suction to pull some of the oil out of the heads breather system. i have looked at the mechanics and physics of the umbrella valve but wonder if the oil is misting enough to be lighter and sucked into the breather? I am at the end of the oil use limit although it still looks relatively clean I am sure it is breaking down. Not interested in an oil discussion but am looking for thoughts on eliminating the drip through the filter. I am not noticing any power drops from over sumping but i am thinking that still may be an issue. I am going to monitor the oil drips for the time being and after my oil change next week. I am not going back with the Royal purple as it might be great oil but man, the odor is terrible and noticeable to the riders behind me...
No real vacuum on that side of the throttle blade. I know there is a tiny bit but nothing in comparison to the other side. Don't worry about the RTV either as long as you cleaned the passages out well. No gasoline being passed and as stated before little or no vacuum being pulled on it. I have had mine done like yours for 5 years, except for a bottle instead of a filter, and all is well. Sure air passes over but no real vacuum is pulled.
my friend did that mod to his, after a while the filter will drip oil so you will have to clean it out
I did my mod a different way, used a canister that can be drained
Nice write up and plumbing job.Having owned numerous Harley's and wrenching on friends bikes,I have never encountered oil puking out of the breather unless the oil level in the crankcase was too high.I guess I have been lucky keeping the oil level about half way up the stick when hot.But, if I ever do get oiley pants from the breather,I now know a plumbing solution.
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Another breather mod, same old stuff
