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I just changed the breather assembly in rocker boxes and when i started bike up there was a loud backfire then normal idle. I looked around engine to make sure there was no leaks and it seems like oil shot out the area behind the spark plug on front cylinder.
Nothing from rear cylinder. Let her idle and no more oil came out. Took a short ride and everything sounds and feels ok. No more oil after ride either. Any idea what could have happened that oil blew out that area?
Last edited by SmittyFXDL; Oct 28, 2019 at 07:08 PM.
Sure hope you cleaned those breather bolt holes realy really good before you put it back together. If you don't get all the oil out you can crack the head and well that's not good. Hope it's all good for you.
Sure hope you cleaned those breather bolt holes realy really good before you put it back together. If you don't get all the oil out you can crack the head and well that's not good. Hope it's all good for you.
Didn't clean bolt holes. Just followed along what manual showed.
I gotta think the breathers weren't breathing, pressure built up, and the "backfire" was something popping. Now, you have a new breather somewhere behind that spark plug...
1. The only place gasket wise that the motor can leak is the rocker base gasket.
2. As SB says, you can hydraulic a screw hole and blow out a piece of metal on the head.
3. I don't think a backfire can blow out a piece of cylinder head or the rocker base gasket without blowing out a bunch of other things.
4. It's possible that some oil may have trickled down and on start with the motor shaking (assuming FXD or Bagger) it simply rattled out. The backfire was unrealated but got you looking.
5. If you used new stamped steel breathers it's possible that you might have installed the valve upside down in one of the heads and have an engine pressure problem. More than likely tho the oil would have had to shot out the breather.
6. I guess it's possible that you could have had fumes just right inside a breather passage and the backfire lit off the passage if the breather is still connected to the intake. That might blow a rocker base gasket but it would be a stretch.
I'm more inclined to believe that it's simply residual oil from the work. Clean it off and put 100 miles on it.
1. The only place gasket wise that the motor can leak is the rocker base gasket.
2. As SB says, you can hydraulic a screw hole and blow out a piece of metal on the head.
3. I don't think a backfire can blow out a piece of cylinder head or the rocker base gasket without blowing out a bunch of other things.
4. It's possible that some oil may have trickled down and on start with the motor shaking (assuming FXD or Bagger) it simply rattled out. The backfire was unrealated but got you looking.
5. If you used new stamped steel breathers it's possible that you might have installed the valve upside down in one of the heads and have an engine pressure problem. More than likely tho the oil would have had to shot out the breather.
6. I guess it's possible that you could have had fumes just right inside a breather passage and the backfire lit off the passage if the breather is still connected to the intake. That might blow a rocker base gasket but it would be a stretch.
I'm more inclined to believe that it's simply residual oil from the work. Clean it off and put 100 miles on it.
I took rocker cover off to check the breather assembly and ask is good and tight. Buttoned her back up and took a 30-40 minute ride and no oil anywhere. Im now second guessing myself and wondering if oil dripped when putting rocker cover back on the first time.
Appreciate all the feedback. I'll post back if anything change. I think she's good for now.
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Breather assembly oil blew out on start up
