crankcase vent

rjw922 · Jul 22nd, 2009, 12:52 PM

My 87' FXLR has an S&S carb with the vent tube routed below the engine with a small breather/filter on the end. My question is that when the bike has not run for a long time, say about six weeks, it pukes a lot of oil out the vent. The previous owner did this set up and I know that it should be vented up to the air cleaner. Is this done to prevent fouling the air filter with oil?
It doesnt appaer to have much blow by or use much oil when run on regular basis.

NEWHD74FAN · Jul 22nd, 2009, 02:09 PM

Probably a little of both...bottom line, oil venting out "usually" means overfilling, splashing & siphoning due to improper routing of the hose/vent or honest to gosh blowby. That said, check location and routing of the tubing (use longer tubing if necessary above the engine exit aways before letting it exit below, so the oil mist is being vented and not "globs"...BTW what do you consider a "lot"?

2000classic · Jul 22nd, 2009, 04:00 PM

Ok, now I'm not real familiar with that model of bike so someone correct me if I'm wrong. Seems this is the standard location for the c.c vent. Down below the engine in 1987. Your puking problem comes about if the bike has sat for sometime? If oil tank is up high, you may have a check valve issue which is allowing oil to leak down when bike has not been ridden for a while creating a wet sump. Just guessing.

rjw922 · Jul 23rd, 2009, 10:13 AM

The service manual shows the vent hose going back to the air cleaner housing, but with the with the S&S carb and air filter the previuos owner ran the vent tube out below the engine. As far as oil fill level, it is between the marks. As far as the amount it pukes, when I started it this spring after storage it dropped about a half quart.
I thought maybe some one else had seen this before. I will try rerouting the line and see what happens.

Found an article in the help section about repairing the oil pump check valve seats. This makes sense and is something that I can handle.
Thanks for replies.

Jul 22nd, 2009, 12:52 PM	#1
rjw922 Start The Engine Ride: 1987 FXLR Join Date: Jul 31st, 2008 Location: MI Posts: 11 My Mood:	crankcase vent My 87' FXLR has an S&S carb with the vent tube routed below the engine with a small breather/filter on the end. My question is that when the bike has not run for a long time, say about six weeks, it pukes a lot of oil out the vent. The previous owner did this set up and I know that it should be vented up to the air cleaner. Is this done to prevent fouling the air filter with oil? It doesnt appaer to have much blow by or use much oil when run on regular basis.

Jul 22nd, 2009, 02:09 PM	#2
NEWHD74FAN Moderators Ride: 2004 Sportster XL1200RS Join Date: Aug 24th, 2008 Location: Camarillo, CA Posts: 4,907 My Mood:	Re: crankcase vent Probably a little of both...bottom line, oil venting out "usually" means overfilling, splashing & siphoning due to improper routing of the hose/vent or honest to gosh blowby. That said, check location and routing of the tubing (use longer tubing if necessary above the engine exit aways before letting it exit below, so the oil mist is being vented and not "globs"...BTW what do you consider a "lot"? __________________ Please stop by the "Self Help section" for maintenance tips, diagnostic codes and much more. >>Self Help Information and Tips<<

Jul 22nd, 2009, 04:00 PM	#3
2000classic Contributor$ Ride: 2000 Ultra Join Date: Nov 23rd, 2008 Location: Watertown, WI. Posts: 190 My Mood:	Re: crankcase vent Ok, now I'm not real familiar with that model of bike so someone correct me if I'm wrong. Seems this is the standard location for the c.c vent. Down below the engine in 1987. Your puking problem comes about if the bike has sat for sometime? If oil tank is up high, you may have a check valve issue which is allowing oil to leak down when bike has not been ridden for a while creating a wet sump. Just guessing.

Jul 23rd, 2009, 10:13 AM	#4
rjw922 Start The Engine Ride: 1987 FXLR Join Date: Jul 31st, 2008 Location: MI Posts: 11 My Mood:	The service manual shows the vent hose going back to the air cleaner housing, but with the with the S&S carb and air filter the previuos owner ran the vent tube out below the engine. As far as oil fill level, it is between the marks. As far as the amount it pukes, when I started it this spring after storage it dropped about a half quart. I thought maybe some one else had seen this before. I will try rerouting the line and see what happens. Found an article in the help section about repairing the oil pump check valve seats. This makes sense and is something that I can handle. Thanks for replies. Last edited by NEWHD74FAN; Jul 23rd, 2009 at 02:03 PM. Reason: Merged posts

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crankcase vent

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