The only thing I can think of to add to Sojourners excellent advice is the possibility of a vacuum leak. This would cause the hot pipe you describe. Check the clamps on the intake manifold between cylinders. Access from left side with 4mm (if memory serves) allen. I clamp the short end in a small pair of vise grips to make the reach easier. I find mine need to be snugged up every spring. Also check ALLvacuum lines.
Jimbo. 1800c, Drag Bars, Drag Pipes, Chrome Wheels, 31T Ring Gear, BadX Extreme Seat, SOTMC Shocks, 200 Rear Tire, Elimination of all Non-essentials, Kingdom of Kicks.