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Thread: Cylinder Head Identification

  1. #1
    Registered User b25bsaboy's Avatar
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    Cylinder Head Identification

    Good afternoon to everyone,

    Several week's ago I bought a collection of parts for Airheads and Norton Commando parts. There was more Norton parts than Airhead but in the |pile I came up with a dirty pair of double plugged BMW Airhead Cylinder Heads. They were dirty as H*#l and took them and got them Vapor Cleaned at a local shop here in Calgary. The difference is amazing, but I have no idea what these heads will fit, thus I am asking if anyone has any idea what I have?
    On the inside where the valves are it is stamped 30/22.
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    Last edited by b25bsaboy; 10-26-2017 at 01:39 PM.
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 1992 R100RT, 2009 R1200RT

  2. #2
    Liaison 20774's Avatar
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    Well, they're obviously dual plugged. I see the date stamp of '77, so my guess is they're likely 1977 R100/7 heads. Here's a link to the heads on my '78 R100/7 after refurbishing:

    https://forums.bmwmoa.org/showthread...l=1#post854525

    The mold number on my heads appears to be a higher number than yours, so that's why I think they're for 1977. I'm not sure I'd know if they were R75/7 heads, though.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
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    I've got a set of spare heads that came from a 78 R100/7.
    Hope it helps.
    Steve

    20171026_185950 (Medium).jpg

    20171026_190018 (Medium).jpg

  4. #4
    Registered User STEVENRANKIN's Avatar
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    Serial number?

    Is that the serial number on the heads? The microfiche for BMW parts should be of help. St.

  5. #5
    Liaison 20774's Avatar
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    No serial number or part number on the heads. As a general rule, BMW never puts part numbers on parts. The number you do see in the figures is a mold number for which there is no information about.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  6. #6
    Registered User b25bsaboy's Avatar
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    Quote Originally Posted by STEVENRANKIN View Post
    Is that the serial number on the heads? The microfiche for BMW parts should be of help. St.
    Thank you for the comment, but Kurt is right about BMW not putting parts numbers on castings. What you do see is a foundry forging number.
    In comparing my heads on the other heads under my comment, it stricks me that the two heads are a matched pair.
    If you look at the L10 - R10 (left and right side)
    1 263 947 (L10((left side)) and 1 263 947 (R10((right side))?
    SiCu is a foundry metallurgical # of what the head material is?
    Si - Silicon, and Cu - Copper which is mixed in with the aluminum for heat treating to stress relieve?
    Last edited by b25bsaboy; 10-26-2017 at 02:53 PM.
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 1992 R100RT, 2009 R1200RT

  7. #7
    Liaison 20774's Avatar
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    The L10 and R10 probably indicates they are 1000cc heads. The SiCu does represent something about the aluminum alloy. I found an old post by Oak where he said the silicon was approximately 8% and the copper was approximately 3.5%. Oak was a metallurgist.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #8
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    does it make any sense to measure the intake and exhaust ports? didn't the the early R100 have 40 mm I, 40mm Exh. just wondering if that could get you one step closer.
    Louie..._/)....

  9. #9
    Registered User b25bsaboy's Avatar
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    Quote Originally Posted by louieskretas View Post
    does it make any sense to measure the intake and exhaust ports? didn't the the early R100 have 40 mm I, 40mm Exh. just wondering if that could get you one step closer.
    Your comment makes sense, as the chap whose parts I bought from also had a 1979 R100RT with I believe 40mm Bing carbs on the machine . Will go look see!
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 1992 R100RT, 2009 R1200RT

  10. #10
    Registered User Rinty's Avatar
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    Rick:

    Dave Anderson (Anderwerks) can figure out what they are, for you.
    Last edited by Rinty; 10-27-2017 at 10:30 PM.
    Rinty

    "When you don't know where you're going, any road will get you there."

  11. #11
    Measure the ID of the exhaust ports and the diameter of the ground/angled portion of the valve seats.
    Anton Largiader 72724
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    Virginia Motorrad Werkstatt BMW motorcycle service and repair in central Virginia

  12. #12
    Registered User b25bsaboy's Avatar
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    Quote Originally Posted by AntonLargiader View Post
    Measure the ID of the exhaust ports and the diameter of the ground/angled portion of the valve seats.
    Good morning Anton! BeforeI went to bed last night, took a micrometer out into the shop and measure the exhaust ports and they are .040 mm. So that answers a few issues.
    The 1979 BMW R100RT that was purchased along with the parts has .040mm Bing carbs on the machine.
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 1976 BMW R75/6, 1992 R100RT, 2009 R1200RT

  13. #13
    40mm (.040 is a very different number) exhaust ports pretty much narrows it down to a '77-era big-valve R100 head. I have a '79 R100RT in parts and I have those same heads. 44mm intake and 40mm exhaust valves.
    Anton Largiader 72724
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    Virginia Motorrad Werkstatt BMW motorcycle service and repair in central Virginia

  14. #14
    Liaison 20774's Avatar
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    Maybe Rick meant 0.04 meters!! I just measured the valves that came out of my '78 R100/7. The intakes are 42mm while the exhaust are 40mm.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  15. #15
    Quote Originally Posted by 20774 View Post
    Maybe Rick meant 0.04 meters!! I just measured the valves that came out of my '78 R100/7. The intakes are 42mm while the exhaust are 40mm.
    ... which FWIW is normal for a small-port (32mm carb, 38mm exhaust) R100 head.
    Anton Largiader 72724
    Tech articles
    Virginia Motorrad Werkstatt BMW motorcycle service and repair in central Virginia

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