Topic: Weird points / high idle / electric issue

[tmgreene32]

I picked up my first bike a few weeks ago, so I'm learning as I go. Got a 73 CB350F. Kindof stumped on figuring out where I'm getting a short from (among other things) which I found out about while trying to fix my engine rev issue. Idle is ok, but it's getting stuck at high RPMs when I let off the throttle - i.e. 2rd gear, 5k rpms, disengage the clutch and stop, motor stays at 5k rpms until i hit the throttle quickly 2 or 3 times to get it down. Cable is not sticking. Anyways, sprayed the boots with carb cleaner, no changes. Thought it might be a timing issue, so went to change the point gap / timing (btw PO had put Hondaman's transistorized ignition on which is nice). Noticed when statically adjusting the points that the continuity test light was always on, the light was strong when I was coming around to the fire mark and instead of going off when the points moved it would just dim, which seemed weird. I ended up pulling the positive cable off the battery and running a continuity between that cable and ground on the bike I'm still getting "dim" continuity. Traced it back to a wiring harness near the rectifier, before whatever has the fins on it, if I unplug the harness the continuity breaks. In the picture attached, when the wiring harness on the right is detached, continuity breaks. When I remove the 3 wires from the rectifier on the left, continuity still exists. So I'm wondering what the thing with the fins is between the rectifier and the harness, and if anybody's seen this cause a short before?

[Bodi]

The "thing with fins" is your rectifier. The metal box with 3 wires is the regulator.
That is a selenium rectifier. These are obsolete and somewhat prone to failure and "leakage". Unless you're keen on keeping the bike stock that should be replaced with a silicon rectifier bridge. The easiest way is to get a combined reg/rect module to replace both units.
Note that selenium rectifiers tend to "leak" a bit after long disuse in storage. That usually cures itself after a while in use. They do not tolerate overvoltage well - even running the bike with no battery for a short time can ruin one. Overall, selenium units are dodgy and should be replaced IMO.
Hanging idle could be sticking slides/cables/throttle shaft, an air leak on the carb insulators, or lean idle mixture - but it isn't from the ignition timing.
Did you measure across the points to check them - coil wire to ground? The light should be on with the points open, going off when they close.

[evinrude7]

http://www.oregonmotorcycleparts.com/vregulators.html

[tmgreene32]

Thanks for the info! I ordered the rectifier bridge. For checking air leaks, I sprayed carb cleaner all over the boots on the intake without any noticeable difference. The boots on the air filter side are cracked, but that shouldn't be an issue right? I was going to do a carb sync when I get a chance next week. Throttle cables are replaced and they definitely aren't sticking.