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Thread: '82 GS650 - E vs. G Head - not what you're thinking...

  1. #1
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    Default '82 GS650 - E vs. G Head - not what you're thinking...

    Hey all,

    I have 1982 650E that I am rebuilding. Last winter I bought a replacement head and long story short, I ended up with a 1982 650 G head instead. I tried the swap and found out the mistake when the cams wouldn't fit, so I put everything back together and did what I could with what I had. I've continued to look for a proper 650E head and they have been hard to come by, so before I pull everything apart again I'm thinking about options:

    1.) I know the G cams won't fit with the E motor, but for the life of me I can't remember if the E and G heads were identical? - i.e. Could I use the G head with the E cams?

    2.) If I can't replace the head, how difficult is it to have two stripped cam journal holder bolt holes fixed? Currently they are helicoiled (stupid, I know....), would a proper repair be filling the holes with weld and re-tapping? or tapping the existing hole larger and enlarging the hole in the journal hole to accept a larger screw?


    Thoughts?
    1982 GS650e - Cafe or Scrambler...that is the question...

  2. #2
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    The heads are the same, but as you found, the cams ARE different.

    I have successfully installed an E head on a G.

  3. #3
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    Am I missing something here? If the heads are the same then shouldn't either cams fit??
    Current:
    Z1300A5 Locomotive (swapped my Intruder for it), GS450 Cafe Project (might never finish it....), XT500 Commuter (I know - it's a Yamaha )

    Past:
    VL1500 Intruder (swapped for Z1300), ZX9R Streetfighter (lets face it - too fast....), 1984 GSX750EF, 1984 GSX1100EF (AKA GS1150)
    And a bunch of other crap Yamahas....

  4. #4
    Nessism's Avatar
    Nessism is offline Forum LongTimer GSResource Superstar
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    Cam sprockets are different, eh?

  5. #5
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    Repairing the holes shouldn't be that difficult
    You stripped out the helicoils?
    Step one - buy a decent inch/pound torque wrench
    1978 GS 1000 (since new)
    1979 GS 1000 (The Fridge, superbike replica project)
    1978 GS 1000 (parts)
    1981 GS 850 (anyone want a project?)
    1981 GPZ 550 (backroad screamer)
    1970 450 Mk IIID (THUMP!)
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  6. #6
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    A helicoil for the cam cap bolts is a good solution.
    Cheap to fix, if that is all that's wrong with the original head I would say go for that option.
    Mixing cam caps and or cams can cause cam
    stick issues, use plastigage to check for proper play.

  7. #7
    rphillips is offline Forum Sage Past Site Supporter
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    Surprised to learn, just lately, the "E" has a roller bearing crankshaft & the "G" has a plain bearing crankshaft, I realize that is the bottom end, but if that main part of the eng. is totally different, a lot more may be different also.
    1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

  8. #8
    Nessism's Avatar
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    When in doubt, look up the part numbers and compare between models. I did just that and proved that the E and G heads are the same. Camshafts are the same. Camshaft sprockets are different. The sprockets need to stay with the base engine, because the cam chain is different between the models.

  9. #9
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    Quote Originally Posted by Nessism View Post
    The sprockets need to stay with the base engine, because the cam chain is different between the models.
    If the chain is different, it is because one might be a couple of links shorter.

    I forget which was which, but I seem to remember that one of the sprockets had 30 teeth, the other had 32. I found that because I had used the 'other' cam because the lobes looked better. While rotating the crank BY HAND for the required two full turns, the engine stopped SOLID after about 1 1/2 turns. Took the cam out, reset it, tensioned it, all that 'stuff', it locked up again. After the third time of ensuring it was installed correctly, I realized the sprocket looked a bit smaller, so I counted teeth and noticed the difference.

    Typing out that last part made me realize: the G has the sprockets with more teeth than the E sprockets.

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