BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: Dave1 on 18 March, 2017, 21:52:23

Title: Differences between A65 engines?
Post by: Dave1 on 18 March, 2017, 21:52:23
So I recently purchased a 1971 BSA A65 Lightning.

The engine in it is a 1965 Lightning rocket ( thanks to Julian on here for helping to identify). The engine needs work, and this has put me in a predicament. Would a 1965 cylinder head work with a 1971 oil in frame? Reason I ask I need to purchase new valve guides, the 1971 cylinder head, had different valve guides from the earlier engines.
Title: Re: Differences between A65 engines?
Post by: Bess on 18 March, 2017, 22:24:06
Hi,
    My recollection is that the 1965 head rear bolts are 5/16 not 3/8.  The rocker cover studs are smaller as the head steady is connected to the head not the rocker cover.