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  1. #1
    CB750 Member Radioone's Avatar
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    Question Head torque question.

    I have been working on a 74 Cb750 k for several months and am ready to start on the motor. The bike was dis-assembled when I bought it but the previous owner said the motor had been “gone through” before he bought it but no other history. The gaskets appear to be new and the motor is clean like it might have a new top end. The motor is dry (no oil) and my guess is that it hasn’t run in many years. I checked compression and it is very low 30 psi or less. I poured oil in the cylinders before checking compression but no help. I also verified that the timing is correct (not 180 out). I think the next step should be to re-torque the head but not sure I want to remove the cam, tensioner, and cam towers. I don’t think I can check the torque without removing the rocker arms and cam towers. Do I have any other options before tearing into it ? Any comments or suggestions are appreciated.
    Last edited by Radioone; 11-14-2017 at 06:20 PM. Reason: Pictures

  2. #2
    CB750 Guru amc49's Avatar
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    Torque is not your issue if you only have 30 psi compression. If the gasket was loose and you are spinning the engine using starter and a battery then the gasket if leaking will squeal or make noise letting you know it's faulty.

  3. #3
    CB750 Member Radioone's Avatar
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    Thanks AMC, actually I haven’t tried using the electric starter, only the Kickstarter. Since the motor is removed from the frame, I didn’t know that’s an option. What is the procedure- positive battery post to starter and negative battery to engine case?

  4. #4
    CB750 Guru amc49's Avatar
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    Needs starter whirling it, all plugs removed and carbs wide open. Kickstart won't turn it enough to get a good reading. Carbs can be off the engine and better. Car battery better but car NOT RUNNING! Your cable hookup correct.

  5. #5
    CB750 Member Radioone's Avatar
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    Great idea, I will try that next. Is it ok to spin the crank with the starter without any oil circulating? Or is it sufficient to add a bit of oil in each cylinder before turning it over. Sorry for all the questions but obviously this isn’t my day job. Thanks again.

  6. #6
    Moderator dirtdigger's Avatar
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    Yes you need to have oil circulating otherwise you are turning the motor over with no oil in the bearings, its fast and easy to hook the oil tank and lines up and cost you a couple quarts of oil.

  7. #7
    CB750 Member Radioone's Avatar
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    I’m on it. Will report back with results. I have my fingers crossed. Thanks.

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