Wirenutt
XS650 Addict
About the most frequent issue with the engine internals would be the timing chain guide and tensioner. It consists of an aluminum frame with some type of plastic (nylon?) bonded to it. That bond will sometimes fail.
Any other parts that may fail are generally easier to get to. In literally every XS650 I've bought, the suction screen in the sump is ripped.
If the area under the left side case is wet with oil, the clutch pushrod seal may be leaking, or it may just be lubrication getting slung off the chain.
If there is oil leaking behind the oil tube going to the head right at the head/cylinder interface, retorque the head bolts in the proper sequence. That stops it 90% of the time. On one engine, I had to torque the head bolts an extra 5 ft-lbs above spec to get it to stop leaking. Not recommended, but it worked for me.
There's a spring in the electric start mechanism that may have gotten weak or worn - that will cause the starter gears to disengage during starting. The engine was not originally designed for electric start, it was cobbled in after the first two years of sales. All stock XS650s have a kick starter. 70s and71s do not have electric start.
Finally, the rotor in the alternator will fail. Not "may" fail, it will fail, but they usually fail gradually, and you can see it coming. Contact Jim on here to rebuild it for you.
These engines are almost as simple as a lawn mower engine. Sturdy, overbuilt, good performance, and with some care will last longer than you will.
Any other parts that may fail are generally easier to get to. In literally every XS650 I've bought, the suction screen in the sump is ripped.
If the area under the left side case is wet with oil, the clutch pushrod seal may be leaking, or it may just be lubrication getting slung off the chain.
If there is oil leaking behind the oil tube going to the head right at the head/cylinder interface, retorque the head bolts in the proper sequence. That stops it 90% of the time. On one engine, I had to torque the head bolts an extra 5 ft-lbs above spec to get it to stop leaking. Not recommended, but it worked for me.
There's a spring in the electric start mechanism that may have gotten weak or worn - that will cause the starter gears to disengage during starting. The engine was not originally designed for electric start, it was cobbled in after the first two years of sales. All stock XS650s have a kick starter. 70s and71s do not have electric start.
Finally, the rotor in the alternator will fail. Not "may" fail, it will fail, but they usually fail gradually, and you can see it coming. Contact Jim on here to rebuild it for you.
These engines are almost as simple as a lawn mower engine. Sturdy, overbuilt, good performance, and with some care will last longer than you will.
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