Oil filler cap on a '96 FLHT - Harley Forum

DamageInc537 · #1 08-17-2009, 05:03 PM

I've had and issue with the oil cap on my '96 electra on 2 of the last 3 rides. The cap has popped off, and just kind of sat ontop of the filler neck, allowing oil to spray over the pipes and under the right bag. the first time it happened was after 45 mins in stop and go city driving in an ambient temp of around 85. that one i understood, because of the stop and go and hot conditions. It happened again on saturday within the first 100 miles of a 275 day trip. noticed it as i went to put my lid back on before crossing into VT. put the cap back on, no problems for the rest of the trip. the funny thing was on saturday, i was not in stop go, generally moving around 45-55 mph, in 85+ ambient temps. During the time that the cap popped I was in some twisties in southern NH hills, so i was generally up and down between gears. the oil cap is an H-D issue with the Digital temp read out, which i must have left on, because the battery is dead so unfortunatly i don't know oil temps. Is this something i should be worried about, or bring it to the shop for? thanks in advance.

unclepsycho · #2 08-17-2009, 10:04 PM

How snug does it fit?
How many miles on your bike?
If it is fairly snug, and popps off, then maybe your breathers are plugged, and the crankcase pressure needs a place to vent and that is the place that it goes.
Normal crankcase pressure shouldnt do that, but if the rings are starting to go, the blow-by could be causing it, but then again, that's what the breathers are for.

DamageInc537 · #3 08-18-2009, 05:06 PM

bike has 31.9 k for mileage and the cap fits pretty snug. is there a way to check the breathers? and i assume i can to a cylinder pressure test like i would in a car? remove plug, gauge in plug's location and crank starter a few times to build pressure? what am i lookin for if i do that ( pressure wise)? thanks for a point in the right direction Scott

unclepsycho · #4 08-18-2009, 09:44 PM

With 31k on the clock, I cant see it being rings, but all motors have some blow-by. only reason for breathers to get plugged with that few miles is from setting too long and maybe too long between oil changes. Might just take off the hoses at the head from the breathers, start it up and see if anything comes out.....
if nothing comes out the little rubber umbrella valve may be stuck shut from setting too long. You could open up the top rocker cover and pry it open, they are cheep, may as well replace it if you go that far..., or puff on a clean hose into the breather opening in the head, to see if you can break the umbrella valve loose that way.

Just a thought.

aceharleywrench · #5 08-19-2009, 11:27 AM

Check your oil level,if it's overfilled it will cause excess pressure.

DamageInc537 · #6 08-19-2009, 05:16 PM

awesome thanks.. will keep you all posted

DamageInc537 · #7 09-24-2009, 08:08 PM

so i found out that my oil filler cap is actually broken, and is prob. the reason for it popping off. apparently the cap is discontinued from HD and is now unavail. I had to go to CCI for a replacement.