charging system upgrade.

been through this in the past, but been away from the internet access for about a year. I have a 77 KZ 650 with a bad stator and solid state regulator/rectifier. I recall being told I can upgrade to a higher output charging system from a newer (79-81) bike, but don't remember how to find my past topics. Please help. Gas prices have finally made it more cost effective to repair the old Kaw than keep shelling out to the greedy oil companies. Old gal started on the first kick after being in storage since last Sept. Runs great too.

It would be more cost effective and MUCH less hassle to troubleshoot and replace the faulty components of the original charging system than to try to convert it to a newer system. It sounds like someone has already tinkered with it as they did not come with "solid state" anything originally. Also, I believe the 1977 charging system has as much, if not greater, output as the later systems. Ed

have been dealing with this problem over three years, as previously mentioned. Installed the DynaS and had problems starting with electric starter. Resorted to stricktly kick starting. She fires first kick, even after sitting for 11 months with just Battery Tender Jr. This particular 650 has some kinda wierd charging system that put out 9 amps max and was only used in the 77 KZ 650. needed more charging power anyway since I am planning a pair of Fiamm horns and more lighting for visibility to others. Took me damn year 10 months to get the bone yard guy to get off his ass and pull the parts I needed. Ole bike burned up one phase of original stator as well as other phase of reg/rect. Had to replace anyway, so the upgrade made sense. Looked at a couple schematics, and the closest I can make out to reg I have puts ignition hot to brown, ground to black, and green to exciter. Since I don't have exciter, gonna leave open. Wish me luck. Loads of thanks to the guys who helped me on this journey. KX RIDERS the best thing the web has to offer us Kaw Krazys

The 1977 charging system, when in working order, has more output than the 78 or 79 systems. When working correctly, I've seen a 1977 charge system get nearly 14v at idle. I'm not sure a 78 or 79 can do that (they are 1-phase).

The Dyna S uses more power than stock, so it will tax the system. However, the 78 and 79 models seem to have more problems than a 1977, when it comes to dealing with the Dyna S.

The main problem with the 77 system is the mechanical regulator. It's somewhat crude.

Since you are getting rid of the 77 system, you should upgrade to a 3-phase system found on later-than-79 bikes. Those have a 3-phase stator/reg/rec but use the same magnet/rotor as the 1-phase system.

When converting from a 77 system to a later system, you must change the cover, rotor, stator, regulator, and rectifier (as they reg&rec are a combination unit in the later systems).

By the way, you cannot use the regulator from a 77 system on the later systems. It uses a totally different principle for regulation.

Sorry for bringing back a 5 year old post....

I am looking for clarification on this topic.

I have a 1977 kz650c with a "custom" and "unique" electrical" system.

I have purchased a 1979 kz650 wiring harness, the intent of running the 1979 stator and r/r.

Can anyone advise me if I'm taking this down the wrong path? or if I'm right, then the part numbers I would need to do the swap.

Thanks in advance

Upgrade?????

Without a doubt, you are going down the wrong path since the 1977 KZ650 3-phase charging system was the best of the various KZ650 charging systems and the 1978/1979 KZ650 single phase is the worst. Why not simply fix the 1977 system?

There were basically 5 different types of charging systems used on the KZ650s.

The 1977 models used a 3 phase excited field system, with a field coil, rotor, yoke and separate voltage regulator and rectifier. This system uses a switched sense wire to the regulator to indicate system voltage and then either energize the field to increase or decrease the voltage created by the system.

For 1978 and 1979 the system was changed to a single phase permanent magnet type system. This system made use of a magneto/flywheel and stator and the regulator and rectifier were combined in a single unit. No sense wire on this system.

For 1980 a single phase permanent magnet was again used, it is much like the systems used for the 1978 and 1979 systems, but the combo regulator/rectifier changed, it has a switched sense wire to indicate system voltage.

For 1981, 1982 and 1983 the system changed to a 3 phase permanent magnet system. The magneto/flywheel and stator changed and the combo regulator/rectifier also changed. There was an additional change for the later 1983 H3 model after engine# KZ650DE052651 where a different magneto/flywheel was used. The sense wire was used on all of these systems.
Ed

This is why I thought of replacing the system. I was unaware of the electrical mess I was purchasing.

The harness across the top is the 1979 harness

From your post I take it you would replace the missing pieces and use the original system, correct?

Yes.

I agree that wiring is a mess, but rather than going through the trouble and expense of replacing the alternator, left engine cover, regulator/rectifier and any other smaller pieces I would find a 1977 KZ650-C1 wiring harness or use the wiring diagram to make one. You should be able to find a used harness at a bike breaker or if you decide to make one, most if not all of the connectors can be bought new and the wiring diagram is available online. Ed

Thanks Ed

I appreciate the quick and concise responses. I will start my eBay search.

Mike

If everything under the left-side alternator cover is all there, then there is not much missing. All you need is a decent regulator/rectifier. It appears you still have the mechanical regulator, and while that can be made to work, it can also be problematic from age/wear/maintenance.

You can get a new one, reasonably at www.Oregonmotorcycleparts.com . You want the VRREM7-KZ reg/rec.

If all you need is a rectifier, a 3-phase, 30-amp (or higher) model can be had for dirt cheap on ebay.

Good news, however I am still worried about the integrity of the harness, with all the splices and such. Doe you have a source for harnesses?

Also is the model you mentioned, the 2 in 1 version?