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#894864 11/07/22 12:04 am
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Spino Offline OP
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Hi folks. I’m assembling a ‘68-ish BSA B44VS from a pile of parts and discovered that I have cam followers with different feet height. The little notes in the parts baggies indicate that the short foot goes inboard (i.e., the exhaust push rod). Cam follower height is same for either foot size, and diameter of shafts match.

PLOT TWIST: I believe some of the parts in this pile came from a round barrel motor. It’s my understanding that those older B44 motors used slightly shorter push rods. Indeed, I have a pair that measure 8 1/4” (old) and 8 3/8” (new). Maybe these followers are from the older motor?

Mostly I’m looking for a sanity check here, but also just downright curious. Sorry, couldn’t figure out how to post a photo. TIA!!


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Different feet height or stem height?

Look through parts book from 1966-1970 and see if they #'s are the same

Feet should have a 1 degree angle

We did a post on this, take a look, very detailed

https://www.classicbritishspares.com/blogs/news/bsa-singles-cam-follower-orientation

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According to Rupert Ratio (find his very useful books on BSA unit singles), the standard pushrod lengths (inlet and exhaust) are for B44 GP 8 1/4", and for B44 (non GP) 8 5/16". He also mentions that BSA thickened the feet of the flat cam followers in 1971, to combat cracking.


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Rupert Ratio does only list one length (other than for the GP) but the parts books list a different part number for the ‘67 round barrel and ‘68 square barrel pushrods, and Peter at Bsaunitsingles.com list different lengths:

41-0592 for ‘67 is 8-1/4"
41-0790 for ‘68 is 8-3/8"

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Looking in the B44 parts books and getting this on pushrods: B44 GP 41-590. The same number for other early round barrel B44s. From engine number EA-101 (round barrel) 41-592 (0592). All square barrel B44s, including the 1967 SS and VR, used 41-790 (0790).

So I think Ratio's info on lengths isn't complete and that there is a difference in round/square barrel pushrod lengths, as Peter Quick lists.


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Spino Offline OP
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Thanks! You’ve confirmed what I thought to be true about push rod length. As for the cam followers, I was talking about the feet themselves. Perhaps the explanation about an update for durability explains why one is thinner?

Here is a photo of the feet:

https://www.dropbox.com/s/c2yr0ld5z5mhhop/IMG_5205.JPG?dl=0

Last edited by Spino; 11/08/22 2:58 am.

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There were different parts numbers for 67 and 68-70 tappets: 41-0668 & 70-7739. I don’t know what the actual difference is.
There were also "thick feet" tappets used in B25 & B50’s that were "less prone to cracking", according to Peter Quick.
I believe (but am not positive) that they are interchangeable.

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Thick and thin feet are interchangeable but you have to check the tunnel in the crankcase for clearance when the foot is at its topmost position on the peak of the cam. When you put these followers in a C15/B40 case that tunnel needs shortening at the bottom as an earlier example of the required mods.


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