KZ650 Sleeper Build (KZ1000 engine transplant)

I did some investigation into my not so high charging electrical system today. Started it up with a known good SH775 regulator that was on my 750 that achieves 14.5 volts.

With that "good" regulator on I could only achieve 13.5 volts at 4000 RPM.

I also had another SH775 as a spare I tried, with the just about the same results (13.4 volts) so I disconnected the plug with the wires attached to the stator and it read 60 volts at 4000 RPM. To me that seems like a low reading, should be more like 70? so I suspect a new stator is in order??

I tried to read the resistance on the stator thru that plug but I got a infinity reading, weird how I was able to get voltage with no issues! 

Tomorrow I will take off the sprocket cover so I can disconnect the wiring and try that reading again right at the bullet terminals. It has to be taken apart anyways if I am replacing the stator. I am pretty sure I tested the resistance on that stator prior to installing it, should have noted it somewhere!

Not sure if its the rotor, probably highly unlikely. Still need to do some digging around before I get too excited, I think there is another stator here I can bench check.

I also found that its smoking a wee bit on throttle raps so I should probably drop down another pilot jet size. I never noticed the smoke too much till today.
 

A good strong stator will put out about 80 VAC.  Most likely a stator issue.

I would have thought it would have been at least 75 volts because that is what I would normally see in a KZ650. I did some digging online and found numbers ranging from 50 to 70V being normal for a Z1 :

z1ownersclub.co.uk/phpBB3/viewtopic.php?t=45636

Maybe at 4000 RPM 13.5V is normal for this system, should have buzzed it up a bit more. Light was on (Canadian build) but on low beam so not sure if that factors in. My test yielded 60V so sort of a mid range result.

I don't have a paper version of FSM so need to check again, and maybe the Z1 version as well.

I am just not sure if 13.5V is enough to charge the battery on a long ride.
 

The headlight on when testing is a good thing, you want load on the system (we used to test cars with "everything on including the rear screen heater) 13.5v is enough to charge the battery however if there is a weakness in the stator it will only get worse not better and a "partial short" will damage your R/R

Wookie58 wrote:

The headlight on when testing is a good thing, you want load on the system (we used to test cars with "everything on including the rear screen heater) 13.5v is enough to charge the battery however if there is a weakness in the stator it will only get worse not better and a "partial short" will damage your R/R



 

Found this on the web :

The minimum voltage to charge an AGM (Absorbent Glass Mat) battery is generally 13.5 volts. For optimal charging, especially during the absorption phase, a voltage between 14.4 and 14.7 volts is recommended. It's crucial to avoid charging AGM batteries at voltages significantly below 13.5 volts, as this can lead to incomplete charging and reduced battery life. 

13.5V - 13.8V: This range is suitable for maintaining a charged AGM battery, often referred to as "float charging". 

14.4V - 14.7V: This range is ideal for the absorption phase, where the battery is brought closer to a full charge.

If I am only generating 13.5 volts at 4000 RPM (normal highway cruising) that is the bare minimum. Its the time spent under 4000 that worries me as I am not always on the highway.

I have been down this path before with other builds so I think it may be in my best interest to look at getting a new stator.

A new stator on a Z1 as compared to a 650 is not a easy swap! Not looking forward to the prospect of doing the install all over again since the one I put on there is perfect and does not leak a single drop of oil.


 

I ended up buying a reproduction stator for a local company for about $180 delivered. The description says it is over wound to generate 10-15% more power output, I also believe it has thicker gauge wiring.

I was looking at a Ricks Hot Shot rotor, that would have solved the issue much easier but the exchange rate and taxes killed that idea. The rotor price with exchange rate and shipping was $410 and the duty/taxes were a additional $140 = $550 total. I can't justify that cost right now, but was happy to find a upgraded stator to try and solve my low charging issue.

 

I continued on today with a few small "busy" jobs on this bike.

I removed some shims on my center stand limit bar because the stand was hitting the LH muffler. The shims were made on the lathe because plain washers were too wide to sit flat.

I also worked on getting the petcock fixed so the outlet lined up with the where the gas hose needed to be and the lever handle could fully swing around as it was hitting the air box initially.

 

 

This is after I turned the outlet a bit to get it closer to where it needed to be and I used a small hammer to punch the lever closer in on the body then cut the excess off the roll pin with a Dremel pink disc.

I then cut out some heat shield material to fit to the bottom of the tank to reflect heat away at the cam cover and a few spots at the front where the oil lines sit next to the tank.

 

Trial fit was OK but the outlet fouled slightly on the oil line so I turned the body more so it was more parallel to the bikes center line.

 

It looks OK from the top with the plug wires out to the side.

 

You can see how tight it is to the carb top but it clears OK, filter clears and gas line has a bend towards the center then back into a top 5/16" "Y" fitting at the carbs.  

 

This is the lever fully opened.  

 

This is the lever fully closed. I hammered in the lever more than 1/8" and shortened that roll pin.  



This shows the routing of the plug wires to avoid the tank bottom on both sides.

 

 

Hopefully there won't be a issue with the heat wicking up from the engine, but better safe than sorry.  
The gas cap lid vent hole has been previously enlarged to increase the amount it can vent out. In the past with my 831cc 650 engine I could hear it hissing when I would pull over and stop on a stupid hot day.

 
 

Normally, I'm not a fan of high output stators for old UJM's, because any surplus power generated gets shunted back to the stator, which leads to overheat damage.  In your case here, using a SH775, it should be good, though.  Maybe a hedge against weak rotor magnets?  At any rate, good on you for going local.  I've read a few "rewind your own stator" tutorials, and one of these days I'll do the deed.  Not that I need one, mind you. It just seems like a fun project.  There is no reason a competent local shop can't do you right.

The stator I bought is a reproduction part probably made in China, its the same one that Z1 enterprises sell. I believe the extra power output is due to better materials and thicker wires than the original equipment that is now a 50 year old design.

The rotor I was looking at buying has neodymium magnets, so it has a much higher power output than a stock unit. 

The Z1 rotor stator combination might be one that could be modified for more power output. The rotor seems like it would be a easy to turn down and install a slip ring channel filled with rare earth magnets. Would be easy enough to press fit that ring on there and put a backing plate so it has no where to go. 

Have seen lots of these rotors turned down to make a button start drag bike starter system. But that is completely removing the outer material to save the inner sleeve, not quite the same thing.