Oil cooler and oil filter housing

82 Yamaha XJ650RJ Seca

The bike came with a Lockhart oil cooler. Do oil cooler perform much of a function on this bike? The plate between the engine block and the oil filter housing makes it a bear to change the filter n I do not like how close the rubber hoses pass by the exhaust. I have owned Airhead BMW motorcycles and on this bike a cooler does not make much of a difference in oil temperature.

What sizes is the oil filter bolt/oil bypass? A 11mm will not fit and a 12mm 6 point socket is very sloppy. I have measured the hex and found it to be .459 = 29/64 = 11.7mm. Sooner or later using the 12mm is going to round over the hex.

Third question. I had not ran the bike in a couple of months and the vacuum operated petcock along with the float valves failed leaking gas into the engine. I noticed the problem when the bike started leaking from the left side shift lever cover. Removed gas tank and drained the engine oil. I currently have the shift cover, clutch cover off the bike and the oil filter removed/oil drain plug out, allowing the gas to evaporate from the engine.
Should I remove and clean the clutch plates or is airing enough? I plan in the spring to run the bike a few miles and change the oil to make sure I cleared the engine of the gasoline.
I am planning to replace the float needle valves assemblies and install a manual petcock.

 

Rebuild the petcock..kit is like 20$ ... the oil cooler does help if you live in hotter climb , you may have an after market cooler so it is possible someone used a standard fastner rather than metric ??

 

The oil cooler does help ( but is not required). They came as standard everywhere but the U.S.
Lockhart is a US company, so all their fasteners during that era would be SAE, instead of metric.