Motorcycle Repair: 1972 CB500 Overheating?, maximum gap, exhaust leaks

Question
I have a 1972 Cb500, it's my first CB and I'm trying to restore it. It runs good at night or early morning when it's cool outside, but in the afternoon, about 90 degrees, after 10-15 minutes of riding it starts to die, bog and feels like it's only running on 2 cylnders. It finally dies after about 5 minutes of running this way. It takes about 15 minutes to get it started again. It has Unifilter pod filters on it and a 100 main jet, could it be too lean? The spark plugs show a light tan color. The previous owner installed automotive looking in line fuel filters, could it be choking the fuel supply? It starts great but idles around 2000 RPM and pops and cracks when idling, (it also has an exhaust leak at the head). After it dies out the engine feels really hot, like it overheated. Any help will be appreciated! If more info about the bike is needed feel free to ask!

Answer
Mark.... First, do a tune-up on it. Adjust the valves (.002" intake and .003" exhaust) and camchain tensioner. Check compression to ensure that you have four strong cylinders firing. Then, remove the points plate and check the spark advancer for proper advance/retard action. Lube up the points cam and reinstall the points plate. Set maximum gap to about .014" on the high point of the cam, then move the points plate around until the 1-4 points just OPEN. Then turn the motor over another 1/2 turn to get the 2-3 points set to open at the F mark.

According to online microfiche, the main jets should be 110s. Pod filters are not helpful for air flow into these engines. If that is all you have then, jet accordingly. Listen for sounds of pinging/detonation under throttle loads. These are signs of overheating.

The idle should be around 1200 rpms, if the spark timing is set correctly and carbs are clean and synchronized. You may need 115 main jets, but start with 110s.

Fix all exhaust leaks.... If you don't have OEM mufflers, more jetting may be required.

Check the fuel cap for proper cap venting. Petcock in fuel tank should have open passageways, once you take it apart. Inline filters won't really impeded fuel flow unless they are plugged up.

Bill Silver