650/750 oil pan mods

I was looking to put a oil cooler on my KZ650 street bike that has a Spectre 750 engine in it.

The current Spectre oil pan has the oil level sensor but I modified it by taking all the guts out and cutting off/sealing up the wire. Unfortunately the O ring seal keeps on leaking despite being changed a couple of times over the last couple seasons. Frustrated by this I bought a KZ750E pan and a stock KZ650 pan in hopes of using one of those to replace it.

I already had a GPZ750 oil pan I earmarked for another project. Using that as a template I modified those other two pans to take oil cooler fitting like the GPZ has. Because of my leak with the Spectre pan I chose to weld plug the GPZ pan to avoid O ring leaks.

All the oil pans were tapped for NPT to -6AN fittings.

The GPZ pan just needed the stock inlet/outlet holes opened up and tapped 1/4NPT. The KZ750E pan casting was blank so new holes needed to be drilled and tapped. The KZ650 pan was drilled and tapped for 1/8NPT thread because I thought 1/4 may be too big for the shape of the cast lug.

The plug the separates the inlet/outlet flow on the GPZ pan is M14, I did not want to buy that tap or find those plugs. I did however have a 9/16-18 tap which is the size for -6AN.I had one -6 flanged plug that I cut the flange off on my lathe and a cut off -6 thread from a bulkhead fitting. The cut off thread needed a plug for the middle, pressed one in then cut a slot with a hacksaw.



From left to right - GPZ750, KZ750E, KZ650







KZ750E pan complete



KZ650 pan complete



GPZ750 pan complete (paint removed, no fittings)

The KZ650 oil pan will go on my bike with the Spectre engine in it. The KZ750E oil pan is going on a DFI fuel injected build I have planned. The GPZ750 pan is going on my 831cc Sleeper bike once I reassemble it.
 

Have you shimmed the oil pressure relief spring[(s) yet?


.

Nebr_Rex wrote:

Have you shimmed the oil pressure relief spring[(s) yet?


.

 

Yes, you can just make out the aluminum washers I made on my lathe installed on both valves. I made a few extras while I was at it.
 

Does the relief need shimming?  Is the oil pressure too low?

Nessism wrote:

Does the relief need shimming?  Is the oil pressure too low?

Shimming the valve is a modification for performance engines, two of my planned builds fit that category.

I did find that the used Spectre engine I bought was down on hot oil pressure as per the FSM test.
I admit I was a little bit lazy with that engine and did not check the oil pump or main bearing clearance when I split it to change the transmission gears. When I did that work it was on a cold garage floor in the middle of winter (excuses)



FSM calls out 28-36 PSI @ 194 F @ 4000 RPM. The actual test result showed 17 PSI with those conditions. Cold start pressure was around 60 PSI (I did test that)

When I bought the engine I had no idea of its mileage. Normally I would inspect or rebuild everything on a engine, but I don't know what I was thinking on this one.

To fix the Spectre motor I bought a low mileage used pump, took it apart and checked it for wear (almost no wear) I am also putting a oil cooler on it with a shimmed relieve valve. I am hoping the replacement pump fixes the issue otherwise I will need to pull the motor. The oil pump seemed to be the easiest fix.