TOPIC:

As in the title says, after sorting out the mechanical problems from a new to me 1978 kz200a, the RR is putting up smoke signals after idling for 10 seconds. Besides the obvious (that the RR is toast), anything else that could cause this? I double checked the wiring diagram and everything is wired up correctly. It's not blowing any fuses, and I can't run it long enough to figure out if it's charging the battery. Am I doomed to just throw a part at it and hope it solves the problem?

Edit: I have a spare Sh775 series style RR, can anyone confirm this will work?

I would test the alternator output. I don't have a KZ200 manual, but the KZ250 should be about 75 VAC @ 4000 rpms. set meter to AC to check the stator, not DC. Disconnect the yellow wires from the stator & connect meter leads there. You'd need to fully charge the battery beforehand with a good motorcycle charger.

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Why test alternator output? Alternator output just gets higher and higher depending on engine speed correct, and it is the R/R's job to regulate that down to safe battery charging levels right? Couldn't I just test the DC power at the battery as the bike is running. If it increases past 14.6 with increasing RPM, then I would know the regulator has gone bad?

It's all part of the test. Do you have one or three phase charging system? Pics would help.
Steve

His bike is probably single phase w 2 yellow wires.

R-To-R: the stator test is easy & gives the opportunity to clean up the connections. you could also clean the reg-rec connections. I would charge the battery with a good motorcycle smart charger & do a load test. A good, fully charged battery is a must. My way is to check & set everything as per the factory service manual before replacing anything. you never know sometimes. Maybe your only problem is the voltage regulator, but I prefer to go ahead & check everything. do a check, double-check my work, then move on to the next thing. most stuff is pretty simple to test, so why not. I always make certain the battery is good before doing anything else.
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I am at work so don't have access to the bike, but it is this R/R. 2 yellow wires and 1 black into 3 prong connector, 1 white/red to starter relay, 1 gray to stator

The battery has been on a tender since yesterday evening, it should be good to go when I get home this afternoon. I will clean up connections and test stator output and report back.

The wiring diagram for the 1978 Kz200A1 shows only four wires to the regulator/rectifier. 2 yellow, 1 black, and 1 red/white.

Is there a chance the gray wire is actually brown? I've never seen an extra gray wire on a Kz regulator/rectifier. Is there a chance someone installed a reg/rec from another model?

On some Kz reg/recs there is a brown wire which is switched 12v and the regulator uses this to regulate voltage. If it is left disconnected, the regulator sends full alternator output to the battery.

The only other wire near the stator, besides the 2 yellow, is the light green for the neutral switch, but that does not go to the regulator.

loudhvx wrote: The wiring diagram for the 1978 Kz200A1 shows only four wires to the regulator/rectifier. 2 yellow, 1 black, and 1 red/white.

Is there a chance the gray wire is actually brown? I've never seen an extra gray wire on a Kz regulator/rectifier. Is there a chance someone installed a reg/rec from another model?

On some Kz reg/recs there is a brown wire which is switched 12v and the regulator uses this to regulate voltage. If it is left disconnected, the regulator sends full alternator output to the battery.

The only other wire near the stator, besides the 2 yellow, is the light green for the neutral switch, but that does not go to the regulator.

I have zero knowledge of the history of the bike. Definitely possible that this R/R is from another model or brand and not original to the bike at all. I will double check this afternoon, but I am fairly certain the wire is gray. I will also double check the routing of the "extra" wire to confirm where it is connecting to.