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Sparks Kokusan stator rewind, DC conversion,wiring upgrade

Joined Oct 2002
3K Posts | 21+
Sunland, CA
Greetings all,

This post has been a long time coming since my receiving of the Sparks rewound Kokusan stator. This started out to be a simple job, but, I ended up doing a bit of refreshing to other parts of the bike that delayed the posting of this thread.

As many of the 2004 owners will attest, the lighting output connection on the stator bus would regularly melt the solder off and you would loose your lights, meanwhile the output to the rectifier would go on without any reported problems that I know of. I remember this solder melting early on being attributed to the "dry" stator, but, as my research would prove out, the dry stator is subject to lower peak temperatures than the "wet" stators of the sister KTM machines.

By 2005 they seemed to have solved the problem, as I bought a 2005 stator from Motoxotica, and had no issues with it.

Some of the other refreshing I was doing was upgrading to a used 2006 tank, used 2007 radiator, this so I could add the cooling fan to my bike and have the thermal well for the fan temp switch.

So there's the history, and here-we-go.

Sparks has come up with a good rewind for the stock Kokusan stator, converting it over for DC operation. The usual practice of floating the ground, and placing the windings in series, ends up increasing the voltage to be regulated to between 120 to 140 volts. With his winding spec the windings are in series, and there is a slight wattage increase, but, the big advantage is that his winding spec has kept the voltage to be regulated to 60 volts, so as to avoid what he calls "warming the frame". I call it circulating current, which in the end will cause a lot of excessive heat.

Quote from Sparks via PM:

"The output voltage of this new spec is 60 volts AC at 8000 RPM, so that seems to work OK.
The original with the two separate windings gave 90 W regulated only 12VAC and 25 W Regulated and rectified DC for the battery. "


With the standard flywheel it's making 120W max this is from the reg/rec to the battery 7000 rpm 14.14 VDC at the battery. (note: this is with the TT 150watt reg/rect and is REQUIRED when making this upgrade.)

120 W RPM 110W
12.85 2000 12.85
13.00 3000 13.00
13.2 4000 13.50
13.80 5000 14.20
14.00 6000 14.28
14.14 7000 14.28

55W 1000 13.00
55W 2000 14.045

No load just the battery 1000 RPM 14.45 VDC

"The alternator windings don't even get warm that's after 30 mins running various RPM's and power so that's good."


Sparks had suggested that I use a larger wire from the battery to the new TT reg/rect as the stock wiring was a bit thin, and he was correct. I think the stock wire from the reg/rect to the battery is around 18 gauge, which is sufficient for the 25 watts or 2 amps that would be flowing through that wire for battery charging or running the fan, as that portion of the stock stator is only good for about 25 watts. The other 80 or 90 watts of the stator output was only regulated to 14vac and supplied the power to the lighting system. (The DC output wire on the TT reg/rect is 16 gauge, however, I ran 14 gauge from the reg/rect to the battery). It was at this point that I realized I should have bought the universal DC conversion Trail Tech reg/rect, instead of the one specific to the KTM/Husaberg as I cut off the multi pin plug and just used bullet connectors to tie in the new stator output wires, and the charging output and ground wires for the new reg/rect.



Sparks rewound Kokusan stator has a high degree of craftsmanship, and he also installed larger output wires from the stator up to where they connect with the bikes electrical system. The stock stator from an 05 is on the left, while the much beefier Sparks rewound stator is on the right.

0713081149_G.jpg


As several folks have found out, if you are doing a lot of slow single track riding the fan will stay on just about constantly. And, if you use the electric start a bunch, pretty soon you are going to end up with a low battery that will not start the motor, as the wattage that was before being used to charge the battery is now being consumed by the fan.

Thus, the conversion to straight DC power for lights, battery charging, fan and other accessories. This is done to put the full output of the stator to the battery and then tap all of the accessories off of the battery to keep the battery fully charged. Another advantage of having your lights come off of the battery is that when you panic brake and kill the motor the lights don't turn off, turning the "oh shoot" moment into one of stark terror in the pitch black.

Also, for me, as I plan on going to a HID main light, and helmet lights, the conversion to DC is required.

So, as I mentioned Sparks had suggested going to a larger wire from the reg/rect to the battery. Well, once I started to really look at the wiring scheme on my bike, I quickly found out that the wire was again a bit thin to be powering the upcoming HID headlight/helmet light set up. So, I just removed all of the stock wiring that connected the stator wiring to the stock reg/rect through a multi pin plug and installed bullet connectors on much larger gauge wire. As well, I removed the wiring going from the stator/reg wire interface to the headlight too. I replaced all of this wiring with much larger wiring as well.

0712081603_G.jpg


0712081604_G.jpg


To accomplish this task I ran two number 14 gauge wires direct from the battery, unfused to the new mini atc fuse holders that I bought from Autozone and mounted on the left hand frame rail just under the seat. I ran one of the #14 wires to one fuse holder, and then on to the reg/rect.

0713081948_G.jpg


The other #14, I made a pig tail for, soldered the wires together and split it to the other two mini atc fuse holders. The output of the other two fuse holders went up to the front of the bike with some nice duplex #16 gauge wire for the lighting duties. I did retain the stock wiring for the tail light set up.

0713081947c.jpg


Up front I cut out the stock mulit pin plastic plug's for the head light, and another unused one that I'm assuming was the stock connection point for the turn signals. This helped clean up that mass of wiring behind the head light mask. As mentioned before, I used bullet connectors to attach one run of the new #16 wire from one of the new fuse holders to the existing headlight wiring to the on/off switch and the ground. The other unused run of #16 for now was just insulated and tucked away for future use.

0713081947b.jpg


0811081552a.jpg


0811081552_G.jpg


0712081606_G.jpg


On all of the new runs of wire, one to the reg/rect, and the other two runs for the lighting, I dropped the grounds off at the battery. There are pro's and cons to this, I decided that I did not want to have all the grounds hooked together as the stock wiring had up by the coil. So, each circuit has it's own dedicated ground tied directly to the battery.

I used 600 volt wire for the added thickness of insulation for abrasion resistance, and I also wrapped all of the wiring in two layers of shrink tubing, for abrasion resistance, to try and keep it as sano as possible, and to keep water out of the crimp style butt connectors used.


0713081947_G.jpg


This is the positive side of the stock DC wiring bus, and goes directly back to the 10amp fuse on the solenoid block. The only remaining stock DC circuits are used to run the fan, and the start button for the elecy stary. I know the picture is a bit blurry but if you look close you can see the original DC connection from the reg/rect to the battery that is now covered with a piece of heat shrink. The other connection that is not visible goes to the plastic plug where the fan plugs in.

0712081611_G.jpg


GARAGE TEST:

After leaving the battery on the battery tender for a few days I fired the bike up and just took some voltage readings with various accessories on. I did NOT have an RPM meter so I cannot truly compare my readings with those from Sparks. I took my readings with a Fluke 77 electronic multi meter. I would also like to mention that I did not take accurate load readings of what the battery charge rate was before the accessories came on.

Battery before starting the bike was measuring 12.9 VDC.

Kick started the bike. Voltage at idle 13.8 VDC. Revved up a bit, 13.8 VDC.

Headlight on 60 watts: idle 13.6 VDC. Revved up a bit 13.8 VDC. (revved up a bit probably equals 3000 rpms or less)

Fan on ( about 28 watt's): idle 13.6 VDC Revved up a bit 13.8 VDC.

Headlight and Fan on: idle 13.0 VDC Revved up a bit 13.68 VDC.

I discussed these values with Sparks. We talked about one of our meters being off a bit to account for the .3 to .4 VDC difference. And I as I stated I'm not sure what my battery was pulling for charge, and it is the stock battery and is now 4 years old. Also, I do not have an RPM meter to accurately check the RPM's for a given load. I also noted that it very well could be the difference between the two different TT reg/rects, as the regulator is what determines the voltage level and could very well account for the small 4% difference in voltage levels.

FIELD TEST:

I went riding at my favorite high mountain riding area the other weekend and ran the whole day with the headlight on, and the fan ran constantly while riding. This riding is all 1st and 2cnd gear riding, with brief excursions into 3rd gear. So pretty much low to mid rev's the whole day. The electric start worked flawlessly during the day with never a hint of laboring due to low voltage. At one point, I left the headlight on for about 10 minutes while taking a break with the motor off, and I hit the button with the light still on, and it fired right up.

CONCLUSION:
After riding all day running the stator at roughly 90 watt's at slow to mid rev's, that's 75% output on the stator, everything worked flawlessly. In fact, as the day went on, the battery seemed to gain strength and turned the motor over more quickly.

NOTE: I WILL INCLUDE A SINGLE LINE DIAGRAM SOON TO THE IMAGES.

Parts list:
One Sparks rewound Kokusan Stator.
One Universal TT reg/rect for DC conversion, for batteries larger than 4amp hours.
25' #14 gauge 600V Red wire. (this is for the un fused sections from the battery to the fuse holders, and from one fuse holder to TT reg/rect + output)
25' #16 gauge 300V Black wire (for ground from TT reg/rect ground to battery).
25' #16 gauge duplex Red/Black 300V wire. (for the two runs to the front)
3-bussman mini atc fuse holders.
packet of 3/16" 16-18 gauge ring terminals (for the grounds onto the battery)
packet of 3/16" 12-16 gauge ring terminals (for the hot leads to fuse holders onto the battery)
6-#6 burndy 3/16" lugs.
packet of 10-12 gauge insulated butt splices.
packet of 12-16 gauge insulated butt splices.
packet of 10 male bullet connectors, fully insulated with slip on insulation sleeves.
packet of 10 female bullet connectors, fully insulated with slip on insulation sleeves.
at least 9' of 3/8" shrink tube, 12' would be best, comes in 3' lengths.
Box of various sizes of pre cut shrink tube in 6" lengths.
packet of 15 amp fuses
packet of 10 amp fuses
100 count packet of 12 or 14" ty wraps.
100 count packet of thin 6" ty wraps.

Tools:
Soldering iron.
Heat gun.
T&B, or other suitable crimping tool for the connectors.
Wire strippers.
Common sense.
Large portion of patience.

Basic Instructions, at least for the 04 USA model.

Disconnect battery ground wire.

Start out by removing the existing wiring that goes from where the stator wires connect to the bike wiring loom to the multi pin plug, including the multi pin plug, that connects to the stock reg/rect multi pin plug. Once you have cut the multi pin plug out, (remember to cut one wire at a time, not all of them together) cover the red/yellow wire that goes to the + DC bus bundle with a small piece of heat shrink to insulate it. This was the original rectified feed from the reg/rect to the battery. You can also do the same to the brown wire that was the original ground wire from the stock reg/rect, and goes to a bundle in a ring terminal that is secured by of the coil mounting bolts.

Remove the stock reg/rect and mount the new TT reg rect.

THE FOLLOWING STEPS REQUIRES PATIENCE AND COMMON SENSE, TAKE YOUR TIME AND PLAN AHEAD ON HOW THE NEW LOOM YOU ARE MAKING IS GOING TO LAY IN. YOU DON'T WANT TO CUT YOURSELF SHORT, BUT, YOU DON'T WANT A LOT OF EXTRA WIRE IN THERE EITHER. MAKE NICE ROUNDED BENDS IN THE WIRES, AND TAKE CARE TO MOUNT THEM IN A WAY TO BEST KEEP THEM FROM GETTING RUBBED THROUGH.

Take two #14 600V Red wires and lay them out from the + side of the battery, up to the existing wiring loom that goes to the rear, up and around the CDI box leave yourself 12" of wire to play with. Cut and strip the ends where they are going to go on the + side of the battery. Twist the wires together and solder them. Put these two #14's in one of the Burndy lugs and crimp firmly. Slide a piece of shrink tubing over these two wires and use the heat gun to shrink it down. And just lay them over the frame to the left side of the CDI for now.

Tie in the new Yellow wires from the Sparks stator to the yellow wires of the TT reg rect. with the bullet connectors.

Cut a length of the red #14 300V wire that will be long enough to go from the new TT reg/rect, and follow the stock wiring loom back to where the CDI box is and around that little loop above the rear fender, be sure and leave yourself about 12" extra to work with. Where you ran the first two #14 wires. This will be the fused wire to the battery, and is your charging wire. Tie this into the Red wire coming from the TT reg/rect with your bullet connectors.

NOTE ON THE BULLET CONNECTORS, ALWAYS USE A FEMALE BULLET CONNECTOR ON THE HOT SIDE. THIS WILL PREVENT ANY FUTURE SHORTING WHEN WORKING ON THE BIKE.

Cut a length of the #16 black 300V wire and route it the same way, and parallel, as the above #14, but when you get right above the battery drop straight down with it. Tie this into the black wire from the TT reg/rect with a bullet connector.

Take the two of these wires together and slip another piece of shrink tube over them from the bullet connectors down to where the black wire will be dropping down to the battery, and shrink it. Then take another piece of shrink tube and put it over the remainder of the red wire going back to where the fuses are going to be. Just lay these wire next to the unfused #14's from the battery for now.

Now take the duplex #16 wire and lay out two runs following the stock wiring loom from where the fuses are going to go, all the way to the front. You are going to drop the black wires off at the battery, so you are going to apply the shrink tube in the same manner as the paragraph above, covering all four wires from the front back to where the blacks are going to drop down to the battery, the another piece just covering the reds back to where the fuse holder are gong to be.

Now we're ready to tie in the fuse holders. I did mine this way I mounted the fuse holders first with two ty wraps around the wires coming out of the fuse holders, then two small typ wraps on either side of the ty wraps holding the fuse holders to keep them from slipping off.

Then I tied in one of the #14 600V wires from the battery to one of the fuse holders with an inline #10 butt connector. Before I made the connection, I took a piece of shrink tube and slid it back over the wire, then made my connection with the butt splice, then slid the shrink tube over the splice to keep it sealed off from the elements. This would be the dedicated fuse for the charging circuit from the reg/rect.

Next, I took the other #14 600V wire from the battery and tied it into the remaining two fuse holders by using an inline #10 butt connector or splice and then twisted the two leads from the fuse holders together and soldered them and put them into the other side of the but splice. Again, I cut a piece of shrink tube and slid it back over all the wires and after making the connection slid the shrink tube over the connections to help keep out moisture.

Now that the feeds to the battery were connected I tied in the feed to the reg/rect to one fuse holder, and the two feeds to the front into the other two in the same fashion that I tied in the feeds from the battery to the fuse holders.

These steps here take some time to do the best job you can to keep everything neat and tidy and to keep the wires from being pinched, or placed in tension to that they will rub through.

Now it's just a matter of ty wraping this new loom to the existing one, and making sure that your wiring to the new reg/rect is tied down so it won't flop around under the tank.

The wires up to the front also need to be tidy'd up and tucked in well with the existing loom. In my case I put female bullet connector on the spare hot up front as well as a male connector on the ground. On the other I cut the existing wiring and added bullet connectors to power the stock headlight.

Reconnect your ground wire and your ready to go!!
 
Good report on Spark's Kokusan rewind. A full DC rewind is on my list so I can run HID.

I am one of the anti-fan guys, as I don't see any need for one, and I abuse my 550 in tight, hot conditions. Look in this months Dirt Bike Magazine and see the terrain the Texas National Enduro ran through. We made the front cover of the magazine! That is our club's property, and I ride it all the time. Nick Fahringer, riding a 450 on the National Enduro circuit, doesn't run a fan, and he is one the gas, believe me.

The problem with the fan is that the stock thermal switch is set WAY too low. I think it comes on around 180 degrees or so, which is well within normal temperatures and not near overheating. So, like you say, the fan runs constantly. Beside, when you install the fan you block half your airflow through the radiator, so of course it is going to run.
 
Johnf3 said:
Good report on Spark's Kokusan rewind. A full DC rewind is on my list so I can run HID.

I am one of the anti-fan guys, as I don't see any need for one, and I abuse my 550 in tight, hot conditions. Look in this months Dirt Bike Magazine and see the terrain the Texas National Enduro ran through. We made the front cover of the magazine! That is our club's property, and I ride it all the time. Nick Fahringer, riding a 450 on the National Enduro circuit, doesn't run a fan, and he is one the gas, believe me.

The problem with the fan is that the stock thermal switch is set WAY too low. I think it comes on around 180 degrees or so, which is well within normal temperatures and not near overheating. So, like you say, the fan runs constantly. Beside, when you install the fan you block half your airflow through the radiator, so of course it is going to run.

Thanks John,

I worked on this one for a while.

I've waited a long time to be able to put a fan on my bike. Most of the time I probably don't need it, but, there has been several situations where it would have come in handy in some pretty extreme conditions. I can see why some of the guys here on the site have gone with the higher temp switch. The only rebuttal I have is that the temp switch is 85C which works out to 185F. The thermo switch is at the bottom of the radiator, or the coolest part. Using a heat gun I have measured the temperature differential across the radiator sitting still between 25-40 degrees, so I would assume that the top coolant temperature is somewhere around 210 to 225 degree's. So, maybe in the future I'll look into trying to find a thermo switch in the 95 to 100C range. Right now though I'm more than happy with how everything is working out.
 
ok so being a thicky with regards electrics this means that by converting AC to DC you can no longer pull the battery out of the equation and run the lights etc w/o it?

it also means that you shove all the electricty through the battery and that means when you stall, when you stop etc that this stuff all still operates?

does the power to the spark go through the battery now? did it before?

i can understand wires being undersize etc. i remember converting my girlfreinds XR2 (thats a small ford hatchback 3DR from the seventies) to 100W bulbs and the fuse was always going so i raised the fuse level and the wires were close to melting!

i'll get this staright in the doc and also ask maddel to grab some of your photos. just need you to confirm my thoughts written above.

presumably sparks could have done this to the old SEM stator?

when is sparks going to do a kokusan mod to the SEM so all old models can be upgraded!!!

c'mon sparks!

regards

Taffy
 
Taffy said:
ok so being a thicky with regards electrics this means that by converting AC to DC you can no longer pull the battery out of the equation and run the lights etc w/o it?

it also means that you shove all the electricty through the battery and that means when you stall, when you stop etc that this stuff all still operates?

does the power to the spark go through the battery now? did it before?

i can understand wires being undersize etc. i remember converting my girlfreinds XR2 (thats a small ford hatchback 3DR from the seventies) to 100W bulbs and the fuse was always going so i raised the fuse level and the wires were close to melting!

i'll get this staright in the doc and also ask maddel to grab some of your photos. just need you to confirm my thoughts written above.

presumably sparks could have done this to the old SEM stator?

when is sparks going to do a kokusan mod to the SEM so all old models can be upgraded!!!

c'mon sparks!

regards

Taffy

There is not a lot more you can do with the SEM regarding more power from the stator due to the lack of steel content. But you can do pretty much the same mod as Dale did, all you need to do is clip the terminals off the two yellow wires from the stator and feed them both into one terminal, by doing this you are pulling full power from the Alternator and wire accordingly in to a Trailtech 150W regulator rectifier which then feeds directly to the battery.
I could do a three phase winding spec, this would pull more power but this wouldn't be cost effective for the extra wattage you would gain.

Regards

Sparks.
 
Taffy said:
ok so being a thicky with regards electrics this means that by converting AC to DC you can no longer pull the battery out of the equation and run the lights etc w/o it?

it also means that you shove all the electricty through the battery and that means when you stall, when you stop etc that this stuff all still operates?

does the power to the spark go through the battery now? did it before?

i can understand wires being undersize etc. i remember converting my girlfreinds XR2 (thats a small ford hatchback 3DR from the seventies) to 100W bulbs and the fuse was always going so i raised the fuse level and the wires were close to melting!

i'll get this staright in the doc and also ask maddel to grab some of your photos. just need you to confirm my thoughts written above.

presumably sparks could have done this to the old SEM stator?

when is sparks going to do a kokusan mod to the SEM so all old models can be upgraded!!!

c'mon sparks!

regards

Taffy

Taffy said:
ok so being a thicky with regards electrics this means that by converting AC to DC you can no longer pull the battery out of the equation and run the lights etc w/o it?"

I would think, that if you wired directly from the DC output from the reg/rect into the lighting system that the lights would still function correctly while the bike is running, just like the AC system did. Since in essence that's what you are doing with the battery attached. Just like in your car, the alternator carries all of the electrical load while you're driving, and recharges the battery, once the battery is fully charged the alternator is just carrying the electrical load, and the regulator is maintaining the correct system voltage. The difference on a car though if I am not mistaken is that the regulator regulates the field strength, or flux density on the rotor thereby making a car alternator much more efficient for a given size. Anyone with any experience will have suffered a flat battery due to a malfunctioning regulator that was supposed to de-energize the field in the alternator and did not. Whereas on our bikes the magnetic field strength or flux density is fixed. The battery is there as a source to get things going. However, Sparks would have to comment on this for conformation as I am not sure of exactly how the reg/rect would function given this scenario.

"it also means that you shove all the electricity through the battery and that means when you stall, when you stop etc that this stuff all still operates? "

Yes. As I have mentioned in another post on another thread, if you are riding at night, and you panic brake and kill the motor, the lights go out. Effectively turning an "oh shoot" moment into one of stark terror. As with a car, you have to be bright enough to remember to turn off the lights or you will run your battery down.

"does the power to the spark go through the battery now? did it before?"

No. And No. The ignition has it's own source both for the Kokusan and the SEM. The only bike that I know of that are that way are the KTM SX electric start models and their off road variants.

"presumably sparks could have done this to the old SEM stator?"

See Sparks response for this one. It's a good question and I had already asked him this question so that I can do the same to my 01 501. This will greatly clean up the set up on the SEM bikes since they have two regulators, one just for the AC, and the other a combo unit for charging the battery. I would think on the older models with the smaller electric starter this would be a huge help so that the battery would be at full charge when the electric start is called on, especially on multiple restarts, or after a tip over and some oil got into the carb. The same can be said for the Kokusan shod bikes as well, except in the case of the Kokusan, when going to the DC conversion, instead of having 1.78 amps max,available to recharge the battery, you will now have 8.6 amps max. That's a 384% increase in available battery charging power!!!

It's kind of ironic in a way b/c the SEM is rated at 140 watts stock, 70 watts per leg, and the Kokusan is rated at 115 watts stock, 90watts, and 25 watts per leg respectively. Sparks would have to confirm this.

UPDATE 8-11-08:

From Mr. Sparks in regards to running without a battery: "The thing about running no battery, if you dump the battery you will need a capacitor to soke up the excess load or you will blow bulbs for fun."

So it appears that you will have to put some small capacitor in there to take up the spikes.

Dale
 

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