1974 XS/TX650 rebuild

[th62]

Stock, the lube system works like this: The motor is wet sump, so oil is contained in the sump. The oil pump is is mounted in the right side cover and linked to the sump via large gallery across the motor. So, oil is drawn from the sump, into the pump and out through a 10mm gallery toward the front of the right side engine cover. The gallery is bunged at the front of the cover and another gallery drilled at a right angle, just before the bung delivers oil to the right side oil strainer behind the round cover on the right side engine cover, the oil is strained and then fed through a small 8mm gallery across the front of the motor delivering oil to the motor. The system is low pressure due to roller big ends and mains, around 6-10psi cold, and around 1psi hot.

The modified system works thus: Oil is drawn from the sump via the oil pump, pumped up the 10mm gallery, past the right angle gallery to the original strainer (now blocked by the stainless screw in barb) out the stainless barb on the front of the side cover and on to the remote filter via a rubber hose linking the two. Clean oil exits the spin on filter via the push fit barb to the cooler via a rubber linking filter and cooler . Cool oil is then delivered to the round strainer housing cover, fills the void (left empty by the removal of the strainer) and into the 8mm gallery across the front of the engine delivering clean, cool oil to the engine.

The sump also contains a strainer through which oil to the pump is strained. Ideally, the spin on filter would be better placed here, however this involves fitting the spin on filter under the sump, leaving it prone to being struck by speed bumps, rocks and road debris. The standard sump filter is prone to being holed at one corner where there is a higher pressure load, so I fabricated a cover from light ally to protect the corner of the strainer.