Author Topic: Upshur Twin valve timing  (Read 282 times)

Offline GordonL

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Upshur Twin valve timing
« on: January 13, 2021, 02:05:07 PM »
I am looking for someone who has built the Upshur Horizontal Twin. The instructions on valve timing are very confusing. I presently have the intake valve opening at TDC and the exhaust valve opening at BDC. Due to the design it is not possible to change the timing of the intake without changing the exhaust by the same amount. Cams for intake and exhaust are fixed on a common shaft. If it is changed to make intake 10 BTDC it makes exhaust 10 BBDC. So far I am not having very good results with intake or exhaust. Also changing valve timing on one cylinder also changes timing on the opposing cylinder. I have reviewed the drawing and my build and I keep thinking that I am missing something. Input welcome.