Engine position when adjusting valve clearance twins

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laxy
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Engine position when adjusting valve clearance twins

Post by laxy »

I have two manuals describing the procedure of adjusting the valve clearances on in my case 1960 650. The fred neil manual describes turning the engine over in its normal direction until the valve opens and set the gap 8thou at this point. The BMS book states turn the engine over until the valve opens then feel for the piston top and turn the engine over further until the piston is at the top of its stroke. I understand about the quietning curves on the camshafts but i
m unsure of which instruction to follow.any input appreciated
Plugsnpoints
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Re: Engine position when adjusting valve clearance twins

Post by Plugsnpoints »

laxy wrote:I have two manuals describing the procedure of adjusting the valve clearances on in my case 1960 650. The fred neil manual describes turning the engine over in its normal direction until the valve opens and set the gap 8thou at this point. The BMS book states turn the engine over until the valve opens then feel for the piston top and turn the engine over further until the piston is at the top of its stroke. I understand about the quietning curves on the camshafts but i
m unsure of which instruction to follow.any input appreciated
When I set the tappets on my twin I make sure both valves are closed-i.e. at TDC on the compression stroke. The other method I suggest is to set the clearance on the opposite valve to what valve is fully open, as in exhaust open, the inlet will be closed and vice versa (one cylinder at a time) You wont be able to set he valve clearance when the cam is trying to open the valve. I hope this helps.
g5wqian
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Re: Engine position when adjusting valve clearance twins

Post by g5wqian »

i adjust mine with the piston at top dead centre when the valves are both shut and not rocking .
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easy way to work it out is you want it so both valves are NOT rocking , if they are rocking you are on the wrong stroke .

one way round youll notice the valves "rock" as you turn engine over past TDC and the other way they will both be still, it is when they are at TDC and still you set the tappet clearance .

this then is when they are on the back of the cam on the clearance ramp [quietening curve ] and not between lobes .

mine are set to .006" thou , it is a bit fiddly setting to exactly .006" with these engines especially being the age they are now , i tend to pull my rocker down to .008" by sticking the feeler gauge between the rocker arm and valve stem and then fine tweak it to .006" .
laxy
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Re: Engine position when adjusting valve clearance twins

Post by laxy »

Thanks chaps for replies. Im in garage today fettling the CSR for the IJR at the weekend. See you all there.
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