Update. I spoke with Jim w/2-Fast and he told me to change the fluid and go for another ride. I did so and the motor again ran well, and I didn’t detect any clutch slippage, I think? But the bottom line is the gearbox fluid became very discolored again, dark purple, after only burning about ½ tank of gas. It’s never fouled up the oil like this before, even after several rides, so I know something different is going on. So I called Jim back again and he told me to check several things.
1. Pull the spark plug to see if it is oil fouled. If yes, this could indicate that the crank seal is leaking and letting gearbox fluid into the combustion chamber. Apparently when this happens, some combustion chamber mixture can also be pumped back into the gearbox, which could be causing the discolorization. I pulled the plug and it looked normal. A little on the rich side but not wet at all. This fact combined with the fact that the motor runs well, does not spooge and does not smoke hopefully rules out the crank seal as a problem. Furthermore, the gearbox fluid level appears to be remaining constant. It could be dropping just a tad but I don’t think so.
2. Check the radiator fluid level for dropping. Coolant level is remaining full. No issues here.
3. Pull the clutch and look for signs of burning. I pulled it, and visually it looked OK. The fibers were very hard in that I could not scratch them with my fingernail. Possibly they are glazed over. I then took out my vernier caliper and measured the plates and springs against Kawasaki specified service limits. All the plates, fiber and metal, were under service limits. The springs were above service limits but just barely.
I called Jim back and we agreed that the best play for now is to replace the clutch. After all, it needs replacing anyway. I ordered OEM fibers, metals and springs, $166, and will install when they arrive in a few days. I really hope this is the problem in that this is an easy fix. It is the original clutch on a 98-model bike. The only thing that bothers me is that I really don’t think I can feel the clutch slipping, and my fluid never fouled up like this before the rebuild. Maybe the fact that the clutch is beyond service limits combined with the power of the new motor was enough to take the clutch over the edge.
I’d appreciate any feedback on this scenario.
Worthy of noting, Jim has been extremely receptive to my questions and has stated that he will be more than happy to fix anything that may have been related to his rebuild.