Isn't the bypass valve in the block just to re route oil if the filter is clogged? If so, it won't really affect oil pressure. I believe the actual pressure relief valve is in the oil pump.When you say rebuilt, do you mean all the bearing clearances were checked and were within tolerance and or the crank was turned for new bearings? And the cam bearings are good?


70 Triumph 650 cc ECTA current record holder