Running issue on xj700 maxim

My xj700 maximx has a rough run. 3 out of 4 plugs lovely brown, 1 oily. Feels like misfire when starting off low revs tick over great. Choke seems to help. Any ideas please? I am new to these bikes, but had xj600 pre diversion 1991 3km for 12 years.... why I sold it, I can't fathom myself????

 

If it is actually oil on the plug I would be concerned about a problem with the rings or valve stem seal. Hopefully not. Have you checked the compression? If not, I would do that. Choke may be adding enough fuel to compensate for the oil if that's the problem. You might try opening the pilot screw on the bad cylinder and see if that gets it firing. It could even be as simple as a bad plug. Try switching the plug to another cylinder and see what happens. If it is not actually oil, but just unburned fuel, and none of the foregoing helps, then I would think that a carb cleaning might be in your future.

 

Black oily after running on the road or just idling a bunch?

 

After riding. I have swapped plugs for those recommended in the manual. Ran smashing..... for about 1 minute. I am concerned it seems pot 3 has misfire and white smoke from that exhaust pipe. Suggests a coolant leak and possible head gasket? No wonder the guy snapped my hand off to sell her to me. I'm gutted.

 

Just wonder if it's worth trying to get it repaired?? Getting parts in uk is not easy, and, if it is head gasket... no idea how much it will cost? Any ideas?

 

You should do a compression test or better still a leakdown test to see if the head gasket has failed. I doubt it is the head gasket. Is the high tension wire on the bad cylinder making a good connection with the plug cap?