Hello. I know you guys get tired of this but I just bought an Ironhead, never had a bike before and have stupid questions. First of all I have a mechanical background and do get my hands dirty. I have spent years with my head under the hood of a 68 FE Ford XL Fastback. So if I can work on a Ford I can work on an Ironhead right. That's what I think anyway.

Here's my question. I have read a lot about oil getting into the primary. I have the opposite issue. Since I just got the bike I thought I would change the oil. So I did. I topped off the primary side as instructed to just where the oil meets the primary oil fill hole, of course I topped of the crankcase side too. So I fire her up. Oil starts spewing from the crankcase breather tube on the right side. And most of the oil from the primary is gone. Rode the bike for about 30 miles before this with no issues, just low fluid level on primary side. Tell me what you guys think, any Correct info is appreciated in advance. Oh yeah 1975 XLH.
Not starting an oil debate but I put 50w on both sides.

 

Sounds like oil is leaking into your crankcase from the primary. I read about that issue on these pages somewhere. Inner bearing seal or primary bearing something as far as I can recall, needs to be replaced.

 

Usually on a Big twin it is the crankshaft seal leaking and the vacuum created by the upstroke of the front piston sucks primary oil past the seal and into the engine.(not sure about an ironhead) It also could be a cracked case or bad gasket. But you have to tear it apart.

I would recommend before you tear into it that you drain all the oil from the engine & primary and refill with the exact specified quantities and then re-try it to be sure. Your enigne could be wet sumping and you overfilled it when you topped it off which caused the oil pumping out the breather. This is probably not the case but I would rule it out before you tear it down. Use a cheap 15w40 HDEO like Rotella for this test. Make sure you have no obstructions in your breather system as well.

 

Hi Ironcam, just curious, by oil fill hole you don't mean the one halfway up the case or the other higher one do you? If so, way too much oil. Should be a oil level screw just above the bottom of the case by the footpeg. Maybe an inch or so above the bottom of the case.