OK, in my continued edjumukayshion with my first Harley experience I need a question answered.

Does a hot engine always mean a lean condition and vice-verse, or, can a twin cam (regardless of 88 or 96) run too lean and not be too hot for the rider?

Just curious.

 

It is the ratio of air to fuel.

To much air-not enough fuel=Lean
To much fuel-not enough air=rich

The factory is forced to manufacture the engines lean to meet government emissions standards. They are also forced to use restrictive exhaust to meet noise regulation.
These two things make for a hotter running engine.

Correct these two things and you engine will run cooler and make sitting in traffic more comfortable.

To lean is not good, engine damage will/can occur. To rich can thin the oil and wash the oil off the cylinder walls and cause damage also.

Best thing is to get the Air/fuel ratio correct.

 

Easiest way to tell the general running condition of the motor is to perform a sparkplug check. Look at the straps on the tip of the sparkplug. An ideal running condition will produce a paperbag color, a lean condition will produce a white deposit, and a rich condition will produce a black deposit.

 

harley-jones and Sincecrazy are right on target. Also, to answer your question, "can a twin cam (regardless of 88 or 96) run too lean and not be too hot for the rider?", you're going to get heat regardless, so there are other methods to reduce the heat. Many of us put on mid-frame heat deflectors, true-duals (to eliminate the pipe under your right thigh), synthetic oil, oil coolers, fans, etc. and these things do help to some extent. But you're going to get some heat because you're sitting on top of an engine. But like was said, the mixture should be correct.

 

put on a thundermax, hi flow air cleaner, and set of good flowing exhaust, and it will run like it's supposed to.

 

Just to add one more thing about the plug reading.

With the ECU controlling the Air/Fuel mixture it is very hard to get an accurate plug reading. The engine can be lean at one rpm and rich some place else. That is why tuners place probes in the exhaust to keep mapping the Air/Fuel ratio at different rpm's.

In the old carburetor days you could do a full throttle run, hit the kill switch, pull the clutch in, stop and check the plugs and get an average idea of a rich/lean condition.

Today, looking at the plugs is a good way for a general idea, but you really can't do a tune by using this method anymore with the ECU constantly changing the Air/Fuel ratio throughout the rpm range.

 

First 1/2 of the question. The ideal af ratio for an internal combustion engine is 14.6:1 Idle and cruse with something around 13.5 under heavy load and 9.1 to 12.1 at excel (initial crack of throttle)
Now, Let us apply this to a HD V twin. The average motor (Remember I said average)can only run 13.9 to 14.2 at idle and cruse without detonation and over heating. The trade off with even those ratios is heat. All the other #s are somewhat consistent +/- a couple tenths.
second 1/2 of question. If your motor was run at maximum efficiency, it does and will fry your a$$. That is why people richen the af, add heat deflectors, oil coolers, and use true duels to relocate the rear pipe.
IMO HD has successfully continued to keep the air cooled V twin within federal emissions standards. The complaining of heat is just that, complaining. It's a harley, add your personal touches to it and if cooling it off is on your list of TTD, cool'er off. Can't wait to see how hot they will be with the new regs coming?