'91 EVO Breather Gear - Harley Forum

botzman · #1 02-18-2008, 09:11 PM

Hey guys,

As I stated in other threads, the more I look the more I find. Pulled the Tappet Screen other day and found some small black plastic pieces in there (3 of them). Almost look like a broken up sink washer. My guess is either the plastic breather gear or the baffle in the cam cover. The question is can I simply replace the gear or do I now need to be concerned with this crap making its way into the lifters, etc. Lifters have 50K on them. Maybe I should replace while Im at it. Man, this thing is becoming a money pit. I had checked the tappet screen in October and it was clear. Havent ridden much since then. Thinking maybe I caught this at the beginning of the complete gear failure. I will pull the cam cover tomorrrow for a good look. Botz

shovelmike · #2 02-18-2008, 10:11 PM

It sounds like you caught it just in time to avoid a major failure. I would replace the lifters. Make sure no plastic chips got into the oil pump, the plastic is much softer than the metal gears but could still jam them.

Trigger87 · #3 02-19-2008, 09:49 AM

I second changing the lifters. I did mine at 50K, and was told by the dealer that they should be changed every 20K just to be safe.

botzman · #4 02-19-2008, 01:16 PM

Hey all,

Opened the cam chest. No pieces in the bottom, breather gear in perfect shape as well as washer. Im stumped. Are there any plastic gears in the oil pump assembly? I do plan on replacing the lifters at this point. Thanks for your time guys. Mike

Trigger87 · #5 02-19-2008, 01:45 PM

I would have bet my paycheck it was the breather gear. I cannot think what or where that plastic would come from...sorry.

botzman · #6 02-19-2008, 06:17 PM

I looked through the cam chest carefully and also the oil passages I had access to with negative results. Im thinking maybe an old o-ring possibly or a piece of gasket, something that got chewed up. It was very brittle so Im not gonna worry too much now that I know the breather gear is intact. Picked up the lifters and now have everything to re-assemble. I guess I'll be holding off on a new bike after all the $$$ going into this one. Have a good day all. Botz

myt evo · #7 02-19-2008, 06:36 PM

Botz, If you're planning on replacing the breather gear replace it with a steel one like an S&S. Before purchasing one though check the bore where the breather gear goes for wear. I don't think there will be a problem with the stock size but they do offer them over-sized. They also offer a breather reed valve which takes the place of the breather gear. No lining up the gears, nothing, just pop it in. I believe it costs just a tad less than $100. I personally have never used one but the next time around that's the way I'll be going.

botzman · #8 02-19-2008, 07:18 PM

Hey MTY...How are ya? I was actually looking into that today. Havent decided what route to go yet. The plastic one is in great shape but Im not a fan of plastic in an engine. Thanks for the input! Botz

94flhtcu · #9 02-20-2008, 10:36 AM

Sup, Botz? I have been thinking, and the only other place that may have a similar "plastic" stuff would be the umbrella in the head. Like maybe the stem that sticks down into the center section of the rocker box. Other than that, I'd like to know where it came from. A chunk of a valve seal?

The only issue about the steel breather...if small metal chunks do make it here, the steel gear will trap them against the wall of the block, and cut grooves. With the plastic one, there's at least a chance it won't scar the case. Having said all that, I use the steel breather as well. It was also recommended to me to drill each of the holes that form the screen, out to the next diameter, maybe 1/8 of an inch. I don't know if it helped me, but it can be detrimental if ya drill off center into the next hole and get a tear goin. I can tell ya that it has no problem breathing and doesn't make a mess.

Hurry up, man. The days are getting longer...

botzman · #10 02-20-2008, 11:19 AM

94,

How ya been? My thought was possibly a piece of a valve seal as well. I dunno. Should have most of it back together by the weekend. I hear ya about Spring coming. Doc says no riding for 6 weeks which is right about when I planned on riding anyway....April 1st. Going out today to get the small things I need to re-assemble. Ill be ready......no worries here. Botz