DR Stator Rewire

It seems my DR needs some more wattage. Following the lead from Procycle I have rewired my stator.

Since I learn by example, and couldn't find a DR650 stator rewire with pictures, I decided to make one myself. Using my electrical/computer engineering know-how, I have, to my knowledge, successfully completed the transformation.

1. To begin remove the left side cover of the engine (i.e. stator cover). There is oil in it so have a bucket ready. There are 11 screws, one is longer than the rest, make sure to mark where it goes. Also, be careful not to damage the dowel pin. If you are careful not to damage the gasket (assuming it comes off with the cover) you can reuse. So don't damage it like I did!:excuseme: Also make a note of how the wires are ziptied to the stator.

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2. Next, remove the piece that holds down the wires with two philips head screws and then the stator itself held in with 3 allen head screws. I also removed the wire holder off of the stator for ease of access.

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3. Right now the stator is wye wound. We are going to rewire it so that it is delta wound.

stator_delta_y.png

wye_to_delta.jpg

stator_dr650.jpg

4. Notice the yellow wires running along the wire loops. Those are the wires labeled A, B, and C that come out of the motor and go to the voltage regulator. Their end connections are all connected together at the wye connection lead, or based off of the wye diagram they are all connected in the "center."

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5. Cut the wye connection, sever the wires and pull them apart. The whole thing is covered in a resin to prevent shorting so you'll need some needle nose pliers, but be careful not to damage the wires in anyway. Once cut you should have 3 different length wires. Then, lay the cut wires out alongside the yellow wires. Use a utility knife and gently cut open the the casing at the appropriate length. (cut as if you were whittling wood so as not to damage the wires underneath) It doesn't matter which wire is connected to which so long as the wye end of the coil isn't connected to its own yellow wire connection. To make sure you don't do this grab a voltmeter set to resistance and touch a yellow wire to each wye end. If nothing happens you're good. If the resistance jumps to some negative number you have the other end of the wire. :bonk:

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6. Connect a wye end to a yellow wire and solder. (I did this one at a time so that nothing got mixed up)

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7. Next you'll need some epoxy. (I had some general purpose from wal-mart that I am hoping will do the job) Mix the epoxy and cover up the spliced connection to prevent any shorting.

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8. Re-ziptie the wires back in place and put it all back together.

The Delta connection will produce 70% of the voltage output and 140% of the current output of a Y connection with the same windings. See Luke's post on Stators Demystified.

That is totally cool. Is it really that simple? Is there a downside? Thanks for the info.

Nice pictorial. :excuseme:

Yes, it's that simple. The biggest potential downside is accidentally damaging something in the process. Also the peak charging voltage will be about 13.2v down from the stock peak of around 14v. Still plenty to keep the battery up. I recommend that anyone doing this mod should install a good voltmeter to monitor system voltage.

Some epoxies won't hold up well to being bathed in hot oil. Ditto for zip-ties. The ones I used on the first experiment got brittle and cracked. Next time I might use some fiberglass string to tie the wires back in place. The solder joints can be insulated with fiberglass sleeve material.

Thanks for the info to allow me to do it ProCycle, I'm glad I have your approval. :excuseme:

My biggest worry is the epoxy. But I'm not too worried about it... The zip-ties I used look just like the ones I took off of the stator so I think I am good in that aspect.

So, what is the difference in power output vs RPM?

I think the actual power is the same, just more current at the expense of voltage. P=IE.

I think the actual power is the same, just more current at the expense of voltage. P=IE.

No. By converting from the Wye to Delta configuration you are lowering the resistance through each of the three legs of the stator. Total power output is increased by about 30% making about 60 more watts available.

Peak voltage is down about 1 volt. The stock stator makes peak voltage right around idle. The modified stator makes its peak voltage at around 2000 rpm. If you're stuck in traffic or idling along on a slow trail shut off the extra lights, heated vest, etc. or you may drain the battery. If you have a good voltmeter you can easily monitor the state of charge in the battery . Run it down as necessary but let it charge back up before shutting the bike off. Here is a chart showing the approximate relationship between voltage and percent of charge.

100 % 12.6v

75% 12.3v

50 % 12.0v

25 % 11.7v

0 % 11.6v

And so, were you able to measure the 30% increase in power?

What are the torque values for the 3 bolts that hold the Stator in and what are the torque values for the bolts that hold the Stator cover onto the block?

Also do you need to loctite the bolts? red or blue locitite?

My manual doesnt have this info and I am trying to swap my stator this week.

thanks!

What are the torque values for the 3 bolts that hold the Stator in and what are the torque values for the bolts that hold the Stator cover onto the block?

Also do you need to loctite the bolts? red or blue locitite?

My manual doesnt have this info and I am trying to swap my stator this week.

thanks!

Typical torque for 6mm bolts is around 9 ft/lb. They don't really need locktite and the factory doesn't use any but it won't hurt anything to use some low strength blue on them. Don't use red unless you never want it to come apart again.

Thanks for the response. the 6mm bolts are the stator but what is the torque for the case bolts?

Thanks in advance!

Thanks for the response. the 6mm bolts are the stator but what is the torque for the case bolts?

The side case bolts are 6mm.

So, the resistance is decreased through the coils which allows a higher amperage throughput, but at a lower voltage. The trade off being a lower voltage overall especially at idle?

So, this allows you to use more accessories without discharging the battery?

this allows you to use more accessories without discharging the battery?

Yes :excuseme:

Here's are some more pics for those daring souls who want to crank out a bit more electrical power from the stock stator.

More details can be found here --> Wye to Delta stator conversion

Here is where you will find the Wye connection terminal

wye_connection.jpg

Cut the three wires away from the terminal connection

wye_cut.jpg

I extended the cut wires with 19ga copper magnet wire

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Since I don't expect the varnish on the magnet wire to hold up to exposure to hot motor oil

the extended wires were covered with some black fiberglass tube. The new wires were routed

along the stator windings and over to the yellow wire connection terminals and secured with zip-ties.

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I chipped the epoxy away from the terminals where the yellow wires are attached.

The new black sheathed wires were routed between the stator ploes and soldered in.

It doesn't matter which terminal each wire is connected to as long as you don't make

a connection that loops back on itself. I used an ohm meter to identify matching wire

ends and then color coded the wires and the terminals red, green and gold so I wouldn't

accidently connect one wire in a separate loop. Look closely and you will see the wire

marked with gold is connected to the terminal marked red. Red is connected to green

and green is to gold. After soldering I gave these terminals a fresh coat of epoxy.

solder_connections.jpg

Edited by ProCycle

Thanks for the pictures ProCycle. It's nice for people to have more options.

I had thought about doing that but since I had no extra wire and didn't feel like chipping away the epoxy, I opted to simply splice into the yellow wires.

Forwarding a question from ADVRider.com. Can the stator rewire be done to all years or is there a cutoff?

Forwarding a question from ADVRider.com. Can the stator rewire be done to all years or is there a cutoff?

The delta mod can apply to pretty much any 3-phase permanent magnet alternator. This includes most bikes made in the last 30+ years. That would be nearly all electric start street bikes, dirt bikes and ATVs. If it has a battery and 3 yellow (or white) wires coming out of the stator it would be a candidate.

Some kick-start street bikes and most kick-start dirt bikes have single phase lighting coils. The delta mod would not apply to them.

Thanks, thats what I figured but you explain things so much better than I. :excuseme:

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