-86 883/1200 conversion. Performance seems unchanged with engine hot, but it is almost impossible to crank over when hot. Like it has a lot of extra static compression when hot.
Could a collapsed intake lifter when hot cause this?
What pistons did you use? did you use the 883 heads stock? Did you get them ported? If you used flat top pistons with the 883 stock heads your compression ratio is very high. You must use the dished type pistons with the 883 stock heads or you can use the flat top pistons with 1200 heads or ported 883 heads. I did that two weeks ago and have to take it back down and add the dished pistons. Also the electronic ignition module for the 883 is different that the 1200 wich makes the timing off at higher RPMS. Also you are probably running dangerously lean. Rejetting the carb should help some. Check you plugs for color. If white then re jet and readjust the carburetor.