Tech: BSA A65 Push Rod Location On Cam Followers

Tech: BSA A65 Push Rod Location On Cam Followers

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Have you ever installed a cylinder barrel and head on a A50 or A65 twin and couldn't figure out which push rod goes to which cam follower? If you are stuck and unsure you are not alone. Truth is lot of builders run into this problem. Today's blog post will show you how to avoid that error so you get it right the first time - lets get to it.

Where the mistake happens

The mistake usually begins when the cylinder head or barrel is removed during a top-end or a full engine rebuild. Many do not consider that each push rod is supposed to go on its own separate cam follower - remember BSA unit twins have one camshaft which means two lobes are for the intake and two lobes are for the exhaust - they should not be confused.

The correct way

BSA A65 Push Rod Tube Location


Alright so let's go over the correct way to install the BSA push rods over the cam followers. First, we we have to understand that there are four camshaft followers in line (this is where the confusion takes place). The two inner cam followers are correct for the long exhaust push rods while the two short inlet push rods are correct for the outer cam followers. Still not understanding? See the photo above -we made it easy for you.


There you have it. Now when you working on your BSA unit twin you do not have to scratch your head (no pun intended) trying to figure this one out. Let's face it - building an engine requires a lot of patience and time, we understand that you would rather be safe than sorry.  As always thank you for reading today's blog post if you would like to chime in please comment in the section below. Thanks for reading today!


  • Ian

    Help needed please. I am stuck in Germany rebuilding my 1967 A65 Lightning. After putting the cylinder head on I have a clicking sound. I have now (eventually) found that the 2 outside cam (inlet) followers make a metallic click as the cam goes over centre. I have tried to mix and match and to blue them but to no avail. Should I lap them in or better to replace.
    Any assistance is greatly appreciated.

  • nigel

    hi guys is the push rod to cam followers position on a65 and a10 the same

  • Jim

    This works for me good I forgot were it all Gos on my 1966 BSA Copper you all a big help .thanks

  • barrie heyen

    saved me a lot of trialing thank you

  • Paul Mooney

    CBS pulls through again. Thanks guys. Time to put my a50 royal star back together.

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