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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
identifying cams
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<blockquote data-quote="A-BCD" data-source="post: 22739" data-attributes="member: 50"><p>I wrote up about these in MPH642 July 2002 !! This is what I said:</p><p> </p><p>"I timed the inlet as close as I could to 105 degrees ATDC at full lift as recommended by Gary. I then clocked the valve timings and got these results:</p><p> </p><p>INLET OPENS 47 BTDC INLET CLOSES 76 ABDC</p><p>EXHAUST OPENS 76 BTDC EXHAUST CLOSES 47 ATDC</p><p> </p><p>EXHAUST MAXIMUM LIFT 102 BTDC.</p><p> </p><p>So all in all, very symmetrical !! As Gary's cams are very consistent, you would probably be quite safe to time them with inlet opening 47 BTDC, you can always check the position of maximum lift."</p><p></p><p>But to quote Ian Hamilton himself, from MPH 558 July 1995: "to time the cam you need to find the position of peak lift. This should be 102 ATDC for the inlet and 102 BTDC for the exhaust. The figure of 102 is nominal and can vary between 102 and 105.</p><p>For those that want the total picture, the inlet opens at 44 BTDC and closes at 80. The exhaust opens at 76 and closes at 44. These figures correspond closely to the 80/40 cam suggested by A. G. Bell as optimum forr a 300 degree duration cam."</p><p></p><p>Gary Robinson supplies these as 'Hamilton 105 cams' and says to time them with the inlet valve at peak lift at 105 ATDC. I believe Ian's theory was that this is the point of maximum piston speed, therefore you should get the maximum charge into the combustion chamber.</p><p></p><p>Cheers, Brian</p></blockquote><p></p>
[QUOTE="A-BCD, post: 22739, member: 50"] I wrote up about these in MPH642 July 2002 !! This is what I said: "I timed the inlet as close as I could to 105 degrees ATDC at full lift as recommended by Gary. I then clocked the valve timings and got these results: INLET OPENS 47 BTDC INLET CLOSES 76 ABDC EXHAUST OPENS 76 BTDC EXHAUST CLOSES 47 ATDC EXHAUST MAXIMUM LIFT 102 BTDC. So all in all, very symmetrical !! As Gary's cams are very consistent, you would probably be quite safe to time them with inlet opening 47 BTDC, you can always check the position of maximum lift." But to quote Ian Hamilton himself, from MPH 558 July 1995: "to time the cam you need to find the position of peak lift. This should be 102 ATDC for the inlet and 102 BTDC for the exhaust. The figure of 102 is nominal and can vary between 102 and 105. For those that want the total picture, the inlet opens at 44 BTDC and closes at 80. The exhaust opens at 76 and closes at 44. These figures correspond closely to the 80/40 cam suggested by A. G. Bell as optimum forr a 300 degree duration cam." Gary Robinson supplies these as 'Hamilton 105 cams' and says to time them with the inlet valve at peak lift at 105 ATDC. I believe Ian's theory was that this is the point of maximum piston speed, therefore you should get the maximum charge into the combustion chamber. Cheers, Brian [/QUOTE]
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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
identifying cams
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