BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: spike123 on 29 Jul, 2022, 12:19

Title: Camshaft
Post by: spike123 on 29 Jul, 2022, 12:19
Hi has anyone bought a hepolite camshaft for a65 with spitfire profile, I just have and the lobes hit my crankcase which I've milled to accommodate . However once I've teamed the bushes and put the cases together, the cam won't turn, I called srm because when I purchased theirs I didn't have a problem, he said that he was concerned that the profile of the lobes are not correct and the way they make the cams people are having problems with them being bent,
So just the heads up and don't waste your well earned cash and don't buy them
Title: Re: Camshaft
Post by: 1660bob on 06 Sep, 2022, 08:24
Hi, i bought a Hepolite camshaft for my A65 Star, standard profile rather than Spitfire as I wanted to keep to the original (1962) spec as far as practicable. I too had an issue with the cam tightening when cases were bolted up and eventually realised that the bearing journals on the cam were not absolutely concentric as it went "loose-tight-loose-tight" when turned. Annoyingly, I had to ream a little more out of my new cam bushes to get a reasonable compromise, and free off the tight spot.

It seems to me that the manufacturer is grinding the cam bearing journals in two seperate operations and they can be a little out of concentricity, not a lot, but they SHOULD be bang on. No isues with lobes hitting cases though. I have just started up the motor for the first time, it runs sweetly but HELL the valve train is noisy as.....so I`m looking into that today (see my seperate post....Bob C
Title: Re: Camshaft
Post by: Mark Parker on 06 Oct, 2022, 07:09
If you introduced more backlash in the timing gears opening up the bushes it will be noisy.
Title: Re: Camshaft
Post by: EDDIE SIMPSON on 07 Oct, 2022, 01:49
i bought some reproduced hepolite valve springs which i didnt fit or like. the wire was too thick and i was worried about coil bound at top speed. potential buyers should be wary of their parts when they are not reproduced to drawing spec.
mark parker your bike sounds so smooth . is the main reason the silencers or the valve gear arrangement?