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  1. #1

    Join Date
    Jan 2021
    Posts
    6

    Default 74 xlch glowing cylinders

    Hi guys I got here from a Google search of my issue and read through this thread http://www.chopcult.com/forum/showthread.php?t=50933

    I'm having one of his issues but couldn't pinpoint what his solution was. Maybe oil pump being out of time, which I didn't even know about? Is that a thing?

    What happens is pressure is getting into the primary because oil just bleeds from every plug ion the primary. It also gushes out of that gearcase breather tube.

    My fear is it stems from when my oil pump plug worked out and I lost all my oil. The motor just kept going and I didn't even know until I stopped got off the bike and saw glowing red cylinders. Cracked the case somewhere?

    Thanks, hope to get some info!

  2. #2
    Senior Member

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    Join Date
    Apr 2013
    Posts
    9,597

    Default

    PRECISELY where were they glowing?

    Perform a compression test because what is not measured is not known. Then you'll know where combustion pressure is going and have an accurate picture of top end condition. Of course if it fails that's a top end pull. A leakdown tester is more precise and they're educational to own.

    Based on running out of oil I expect your top end is fried (they overheat first) but other damage may have been done due to lack of oil pressure.

    Don't spend any money until you know the full extent of the damage
    since a complete Ironhead overhaul is often more expensive than the motorcycle is worth. That's why many are parted out instead of repaired because only exceptional (or sentimentally valued) Ironheads are worth dropping serious cash. If you have deep pockets that may not matter. Your toy, your call but best to get all the cost info so your choice will make you happiest.

  3. #3

    Join Date
    Jan 2021
    Posts
    6

    Default

    I can't remember detailed exactly, it's been a few years, but looking back I remember seeing red hot steel and I think it was just generally right in the middle of the cylinder which I figure in my imagination was obvious because I was running it without oil for miles

  4. #4

    Join Date
    Jan 2021
    Posts
    6

    Default

    Thanks btw

  5. #5

    Join Date
    Jan 2021
    Posts
    6

    Default

    Definitely sentimental and it's still sweet! My uncle bought it brand new in 74, and I've been riding it for 25 years now, until now..


    Back in 80s
    Click image for larger version. 

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    Fixed up after it was worn down about 10 yrs ago
    Click image for larger version. 

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  6. #6

    Join Date
    Jan 2021
    Posts
    6

    Default

    Hey man, so if I do a leak down test that will tell me the percentage I'm losing. ...but I'll essentially be looking for the leaks which probably valves and is it possible what I described and pressure getting in the primary from a crack or could it ? There should be about zero pressure in the primary right? After typing that I'm now thinking I could just take that primary off and see what's happening with the engine running?
    Thanks

  7. #7
    Junior Member

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    Join Date
    Aug 2016
    Posts
    6

    Default

    Compression test will tell you if the topend is fried. Good first step. The ole ironhead is not going like running without oil.

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