Author Topic: B25ss Camshaft marking valve timing  (Read 185 times)

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cornishbeezergeezer

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B25ss Camshaft marking valve timing
« on: 17 March, 2019, 17:23:49 »
HI guys need some help, I have a 1971 bsa b25ss goldstar 250 and have had do do some engine work, when removing the inner timing cover the cam dropped out..... :-[  now this is the problem my bsa book says there should be a dash and a v mark on the cam, my camwheel has a DASH and a DOT... which are5 1/2 teeth apart..
if you place the cam so that the keyway is at 12 O'clock the DASH mark is 2 teeth anticlockwise from the centre line of the key way, and the DOT is 3 1/2 teeth clockwise from keyway centre line.
My BSA book says use the V mark which should be 2 teeth clockwise of the key way. THERE IS NO V MARK.
 so can anyone help me and tell me how i should set the valve timing... i will try to add a photo of my cam markings ....help please...

DerekAnderson8

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Re: B25ss Camshaft marking valve timing
« Reply #1 on: 17 March, 2019, 18:44:52 »
line up the dash mark with the mark on the crank pinion, you tube explains.

https://www.youtube.com/watch?v=myltpKxTxkY

 :)

cornishbeezergeezer

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Re: B25ss Camshaft marking valve timing
« Reply #2 on: 17 March, 2019, 19:06:54 »
Hi Derek  I have sen that video you have linked t but it contradicts with the BSA Manual which has this image...which is all confusing...

DerekAnderson8

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Re: B25ss Camshaft marking valve timing
« Reply #3 on: 17 March, 2019, 19:24:28 »
it says it there, later engines have only one mark on camshaft. Set it and turn engine over by hand if the valve fouls the piston you will soon know about it.

 ;)

Rupert

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Re: B25ss Camshaft marking valve timing
« Reply #4 on: 18 March, 2019, 20:33:38 »
Hi, don't trust the timing marks. I've built engines and set them as per the bsa manual and used the V and had valves touching the piston.
Whether the camwheel has a dash, dot, V or both, check the mark or find out where it should be as shown in Ratio vol 1 I.e, the tooth to use should be at 12 o'clock with both cam followers equally raised at tdc on the exhaust stroke.
If at tdc exhaust with both followers equally raised the 12 o'clock falls midway between two teeth advance the camwheel to the next tooth.