TOPIC:

The book says if your battery is too low I think under 90%, the rectifier won't charge it.
Theoretically, if you had too much of a drain on your electrical system, too much draw from the halogen, and too much draw from the coils, then you potentially could have been drawing more power then the rectifier could provide.

To me it sounds like a combination of problems.

The battery may be bad, or simply discharged a bit.

The regulator may be bad or it could be dirty connections causing a low voltage on the regulator's sense line. In the latter case, the regulator then compensates by over-charging the battery. Either possibility could explain the over-voltage you are seeing. It should never be above 15v, and with an modern regulator, it probably should never be above 14.5v or so. Or it could be a combination of the two possible problems. If you open the regulator per FSM and the regulator contacts look corroded etc. then it's probably a combination of the two. If the regulator looks shiny and clean on the inside, along with the contact points, then you likely have issues of voltage drops on connectors and switches due to dirt etc. The fuse holders are usually at the top of the list of likely voltage drops.

The voltage drop issue is exacerbated by the increased current-use from the Dyna S.

The good news is that it won't cost anything to clean the connections. The downside is that it takes a bit of time and effort... something for a nice warm day.

loudhvx wrote: To me it sounds like a combination of problems.

The battery may be bad, or simply discharged a bit.

The regulator may be bad or it could be dirty connections causing a low voltage on the regulator's sense line. In the latter case, the regulator then compensates by over-charging the battery. Either possibility could explain the over-voltage you are seeing. It should never be above 15v, and with an modern regulator, it probably should never be above 14.5v or so. Or it could be a combination of the two possible problems. If you open the regulator per FSM and the regulator contacts look corroded etc. then it's probably a combination of the two. If the regulator looks shiny and clean on the inside, along with the contact points, then you likely have issues of voltage drops on connectors and switches due to dirt etc. The fuse holders are usually at the top of the list of likely voltage drops.

The voltage drop issue is exacerbated by the increased current-use from the Dyna S.

The good news is that it won't cost anything to clean the connections. The downside is that it takes a bit of time and effort... something for a nice warm day.

Battery was brand new. However my mechanic did tell me, when I went to get inspected, that he had to add acid to the battery, which is an indication its getting to hot and overcharging. I called him the other day and he said the issue I am having sounds like reg/rec. Hes like 65 years old and only works on old bikes so hes knowledgeable. However I like wrenching my own bikes so im going to sort this myself.

Fingers crossed its just the rectifier. Also the fuse holder is in a sorry state. last summer the area around the primary fuse holder (the area inside the fuse box whcih holds fuses 1 2 and 3) melted around fuse 1. I just taped it back with electrical tape. I should have swapped in the new one. Will let you know how it turnsout.

Look at replacing your old fuse holder with a modern blade-fuse setup. Blade fuses are fare easier to get while on the road than glass tube type

Move0ver wrote: Look at replacing your old fuse holder with a modern blade-fuse setup. Blade fuses are fare easier to get while on the road than glass tube type

Thanks for this. Will do!

Ah, well if you've been having issues with overheating in the fuse holder area, there is a good chance that has a lot to do with the over-charging issue.

I don't think it will be the rectifier, since they usually fail hard, and when they do they either will smoke/melt, or you won't get any charging happening. You are getting over-charging, so that means regulator or bad connections/contacts. Usually when you get over-heated fuse holders, that means other parts of the harness will be dirty too since it all got the same heat/dirt/water history.

loudhvx wrote: Ah, well if you've been having issues with overheating in the fuse holder area, there is a good chance that has a lot to do with the over-charging issue.

I don't think it will be the rectifier, since they usually fail hard, and when they do they either will smoke/melt, or you won't get any charging happening. You are getting over-charging, so that means regulator or bad connections/contacts. Usually when you get over-heated fuse holders, that means other parts of the harness will be dirty too since it all got the same heat/dirt/water history.

Oh theres no dirt / water on the fuse box or harness. A few months ago, maybe 6, the bike shut off, I looked at the fuse holder and the main fuse melted away from the two snap holders they fit into. That area actually melted. I got a new fuse and simply electric-taped the fuse to the connections. Probably not the best idea. I will change the fuse holder first and THEN check the voltage across the battery. I took the battery out today and its charge level was 12.02. I now have it on battery tender charger, charging. battery is literally 2 months old. Yuasa lead acid battery. The fluid levels were fine, but the charge was low. Of course its been sitting out in sub freezing temps too. Now its in the warm toasty house, charging.

I meant dirt and/or water over the course of 40 years which has corroded or oxidized the fuse holders and their crimp connections to the wires. Even if someone cleaned the dirt out, the corrosion could be causing the reduced surface contact between wires and brass fuse holders. That results in excess heat and voltage drop.

Before you replace the fuse block, you're going to want to figure out what melted it in the first place...

Are kz650 reproduction harnesses available? It might be worth replacing the main harness and the reg/rec anyways for peace of mind.

Move0ver wrote: Before you replace the fuse block, you're going to want to figure out what melted it in the first place...

Are kz650 reproduction harnesses available? It might be worth replacing the main harness and the reg/rec anyways for peace of mind.

Yes, I have a reproduction harness that ive had for a few months. This is the state of the fusebox now.

And in re the melted fusebox, I searched the forum and found this is a common problem on some KZs and is not indicative of a greater problem:

"This has been a problem with these bikes since they were new. Fuse clips get dirty/corroded the fuse will heat and eventually melt. Also due to the heat most likely the plastic in the fuse box that puts extra pressure on the clips to make a tight connection to the fuse has melted, so insufficient pressure on the clips to the fuse it will run hot even with perfect contact. The best thing to do is change the entire fuse box to modern blade fuses. Otherwise tie a ziptie around the fuse clip to secure it to the fuse with more pressure."

Bike is in otherwise great shape. Testing the voltage across the battery the other day and it was 14v at idle, shot up 10 16v then 15 v at 3k Rpm and DROPPED to 12v at 5k rpm.

Here is the current fuse box and the new one I plan to put on tomorrow.

FYI these fuse box clips were prone to melting and was a common problem back in the day. I was going to switch to blade fuses, but bought the reproduction fusebox you see below before I knew switching to blades was an option. When the clips melted, I just wrapped the connector and fuse in electrical tape and drove it like that for a few weeks.

Well you know it’s charging! Possibly your regulator isn’t getting a proper signal, or it’s not working. Take your wiring harness plugs apart and look for hot spots or bad connections. Don’t buy a Chinese regulator.