Howdy,
I just rerouted the crankcase vent line from the carb to atmosphere and I'd like to know what filter(s) are suitable to run on the end of the line. Someone mentioned a filter from a NAPA auto parts store? Any further descriptions and or suggestions would be greatly appreciated.
Thanks for the help.
BigR
I rerouted mine so that it exits at the bottom of the bike and have no filter on it. Tested it with and without a filter on a dyno and got better results without.
I ...Tested it with and without a filter on a dyno and got better results without.
Please tell us more. How much difference? Same dyno, same day, same temp, etc?
I have seen thorough documentation of dyno tests showing that there is no measurable HP difference with one of those crankcase breather valve/filters installed, but never a test with just the filter by itself. It would be interesting to find that something even simpler and assumedly even more free breathing, such as one of those vent filters made by K&N for this purpose, made a difference.
I use a filter on both vent ubes on mine. Yeah, I know, the chance of the thing actually sucking in a small piece of wood or something is really slight, but what the hell, the filters are cheap. Besides, it'll keep the spiders and bugs out of it. ;=)
__________________
BB
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I only have my dyno sheets for the first and last run. Other things were changed in addition to the breather tube. I ran the tube down behind the air cleaner, behind the bottom of the pushrods and over the timing cover to the bottom of the bike.
The breather do-dads are just another way for someone to make money,like selling snowballs in the winter.You will not find any power in one of those deals unless it's a vacum pump.
Your breather CANNOT suck anything in,because there's a one way valve(umbrella valve)in the rockerbox that only opens to internal pressure.Out the back breathers are a different story.
I've seen 2 to 3 h.p. on the dyno with an efficient breather system.
The major problems with a filter are: no one keeps them clean,and if you have a lot of oil discharge on a long trip it will restrict the efficiency.
Vent to the atmosphere, but be careful if you ty-wrap the hose/s,that you don't crimp them off.
John
johnsachs, what do you mean by "out the back breather". I have a 1990 Evo with no umbrellas in the rockers. Are you refering to 1992 and earlier? What are your thoughts on not running a filter on 1992 and earlier Evo?
I never run/ran a filter on a breather line.YOU WON'T SUCK ANYTHING IN.If you were able to suck something in,then there would be a lot of engine explosions from the line sucking fuel standoff from the air cleaner.
I put over 91,000 miles on an 88 softail springer. I ran the crankcase breather hose along the bottom right side frame rail back to over the top of the 2 short support pieces that bolt the exhaust bracket to the frame. Never used any kind of filter and never needed a top end on the bike except for cylinder base gaskets and rocker box gaskets. Sold it in 98 and the lady that bought it is still riding it with no top end yet.
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Ed Y
2002 FLTRI
I yam what I yam.
Not exactly sure how they came stock as I never had a new one. Probably either used to oil the chain or run into a T and went to the primary chaincase. Everyone I've seen was just run to ground though.
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Ed Y
2002 FLTRI
I yam what I yam.
Yes, another stupid question. Has anybody just put their finger over the breather hose while the engine is running at different RPMs to see if there is any suction?. I know I haven't ( I'm too fricken lazy to disconnect my filter to find out). Why do they sell air filters for crankcase breathers if they don't require them? Another ripp-off?? Does anyone know the real facts?
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