650 Mod's 78 Fighter Build

Don't we all wish we could have more saddle time... I can't complain as well as I closed in on around 5,000km this year on the old girl. Perfect, that's a good ball park for me. My rear right now has flat spotted so hard it's actually starting to feel soft and the front has some serious cupping going on.

Thanks for the tidbits!

I replaced my wheel bearings so my front tire doesn't get "cupping" anymore.
Steve

Hey Steve! The wheel bearings on the nose end of the bike are brand new as of last season with maybe 5,000 miles on them. I think what was happening here is just the compound of the tire wearing differently due to the road conditions up here. Alot of the secondary highways are "chip seal"- they lay ashpalt down then drop gravel on top, and it's up to the traffic to pack it in. So you can imagine how rough some of these roads are on softer compounds.

Any tips on where to get a decent gasket kit?

Devin

I hope everyone's riding season has been good so far. I've only been out for a few rides as the weather hasn't been too nice up this way.

One quick question about charging. When the bike is off, I have 12.3 or so volts on the battery. When the bike is running, i've got 11.8 volts. Rev up to 4500 rpm, I might be at 11.9-12 volts.

I know I should be running higher voltage while at that rpm, but i'm also running a dyna ignition. Is this where I should be running for voltage with this set up? Or should I start chasing my charging system a bit?

Thanks!

You bike's charging system definitely has a problem. Use the instructions in the CORRECT Kawasaki Service Manual to troubleshoot it and identify exactly where the problem lies. Remember that there were 4 or 5 different charging systems used on different KZ650 years/models, so be sure to find the manual for your bike's exact year and model.

Hi Ed,

Yeah, I was starting to think that way when it isn't jumping voltage at higher rpm.

I do have the proper Kawasaki manual for my girl (78 kz 640 c2). So i'll be digging into this a bit later and starting the process.

Thanks for the input!

I finally had some time to dig into the bike and get some testing done on the charging system. Checked connections to start, and all is well there. So I started going through the manual and working through the tests. The dynamo voltage test comes back completely dead, 0 voltage at all flowing out. So I tried the first resistance check (armature resistance), and got an ohm reading of 0.8, higher than the specified .32-.48 ohm. I then did the open resistance test to see if resistance was infinity, found it was not. So it looks like I'll be trying to find an armature/stator or the old girl...

Re-tested the stator and found that everything is ok with it. Dug into the charging system a little more and found melted connectors on the stator side of the connector with some melted wiring. Did the FSM test on the reg/rectifier to find it having an open short in it.

My question here is what causes the wires to heat up and melt? If the reg/rectifier goes, does the 75V coming off the stator heat the wires up and cause problems? Should I be digging further into this in case I replace the reg/rectifier and have it happen again?

I've ordered in a new reg/rectifier for the bike to swap in.

Dug into the charging system a little more and found melted connectors on the stator side of the connector with some melted wiring

This is a sign of a bad connection in the connector. The current will flow but could not really as should.
The result is the current rises = more heat at the bad connector = melting the connector housings = more current more heat
until some component will burn through = no current and voltage.

Ohm´s law U = Voltage (V), R = Resistant (Ω), I = Current (A)mpere

U = R * I
R = U / I
I = U / R

Rocco,

This makes perfect sense to me, thanks! I have to chsnge some wiring out before the new stator goes in, so i'll also be sure to check connectors along the way and the full wiring length for any cracks or worn areas. Thank you for the break down.

I think I found the deep seated cause to my charging issue on the 650. I have a 78 650, so I have the single phase stator. I'm running a Dyna ignition on the bike, so this is drawing more current than the system can put out (therefor low charging voltage).

I've read some posts on here about replacing the single phase stator with a 3 phase stator and reg/rectifier. But I want to make sure I'm getting the right parts to do it. I have a stator from a 1980 650 with the 6 prong connector to the reg/rec, and a reg/rec from an 81 750 with the corresponding 6 prong connector to the stator. Do I have the right parts chosen to do the swap out to make my old girl happy in the charging world?

Thanks!

Here, this should help you determine the correct parts.