Note while this is specific to my air-cooled V-twin, I believe other air-cooled motorcycles could experience this problem. I've presented this problem to several people, but no one has a viable solution yet. I'm hoping someone here might enlighten me.

My '95 H-D Sportster 883/1200 (60K miles) is overheating. The oil temp (in the tank) runs as high as 230 deg F. It will heat up to 210 F idling or at 70 MPH, just faster with the latter. It didn't used to get over 200 F.

Bike was recently converted from an 883 to a 1200, but was overheating prior to this. Added an oil cooler with 180 F thermostat, but did not see any significant change. It was running on synthetic oil, but changed to standard (H-D 20W50) for the conversion. No changes.

Valves(Gauge Valves) showed evidence of running lean (grey). Had valve job performed. Rejetted carburetor (has high-flow air cleaner and aftermarket exhaust) with a 45 slow jet (40 original) and a 180 high-speed jet (170 original). The high-speed jet change did slow the heating rate, but did not lower the peak temperature. Went up to 190 high jet with little change.

I'm using the needle from an '89 Sportster (more aggressive "curve") and have installed new gaskets, etc. in the CV carburetor. No Dynajet. I also retarded the ignition about 3 degrees.

My gas mileage dropped from consistent mid-50's to less than 40 MPG. Some of that can be attributed to the conversion, but the mileage dropped to the mid-40's around the same time the bike started getting warmer than normal.

Something just isn't right. The temperature gauge is good. Oil pressure is good. The gas tank/filter may be dirty or clogged, which I'm checking out now. However, I don't believe that would cause the bike to run hot.

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