How To Get More Power From Your Honda Motorcycle XR650R

you’ve gone out and bought your dream bike, a Honda XR650R. You’ve spent the extra $$ to install the uncorking kit on it, and the improvement is phenomenal! This thing rips! Now, you take it out for it’s first night ride, and you immediately start looking for how to change the double “A” batteries that power the flashlight some Honda technician glued into the front number plate as a joke. So, you go out and buy a Mr. MegaWatt, quadruple beam, uranium isotope/halogen hybrid headlight and install it, only to find that the big XR is seriously lacking in the electron pumping department. Before you go out and spend the minimum 100 bucks to have your stator re-wound, plus endure the worry of EconoShip losing it on the to and from trips, take a few minutes and skim through this page.

Stator from US Model Honda XR650RHere is a picture of the stator from the North American Honda XR650R. The two larger, black tinted, windings at 11 O’clock are the ignition primaries. The other four, from 10 to 6 O’ clock are the AC windings for running the lights. Now notice the empty spots from 12 O’clock to 5. These are what you can mod to increase power output for headlights other than the night-light that comes stock. I found this to be an easy process. You electrical gurus might find better ways to do it, and point out any flaws, but I will tell you what I did, and can say it works. I put 70w of halogen on the stock stator with poor results. Yellow light at idle, and white light only at mid throttle and higher. The finished product provides bright, white, light at idle and it just gets better from there.

This mod will only cost you around $30, a few bucks more if you need to replace the left cover gasket like I did. See the note below the following parts list. It will take you a few hours to do. A vise with soft jaws to hold the core and a comfy chair to hold your monkey butt during the winding process are also a major help. Here are a few part numbers to help you along:

Magnet Wire, 1lb roll, #501-MW18H-1LB $ 9.08
3M Epoxy, #2216
Originally I was getting this aerospace spec. epoxy from Mouser. They no longer keep it in stock and require a large amount to be ordered. Many other suppliers carry it, but sell it by the 6-pack for around 100.00. You should be able to find single packs on the net.

Thanks to Craig for pointing this out, and finding a viable replacement made by Devcon. It can be purchased at many hometown hardware stores. I have not tried it on my own yet, but he and the specs say it will work. Craig states it was slightly harder to apply due to a thicker viscosity and shorter working time. He suggests making small batches and doing only a couple poles at a time.

New Gasket: 11395-MBN-670
If you are careful removing the cover, the gasket seems to want to come intact with it. Use a razor to make two cuts, one either side of the harness grommet, and remove that piece. Reinstall the piece and seal with good silicone after the wiring is done. Wish I had thought of this before I wrecked it!

Start the project by removing the left cover and stator from the bike. Don’t lose the two dowel pins at the 11 and 4 O’clock bolts. Lay the cover on a bench and remove the 3 bolts that hold the core, and the 2 bolts that hold the magnet pick-up. Before you pull the core off the cover, note the location of the two ignition windings, and the routing of the wiring under the core. If you have a digital camera, there will be no questions asked. Remove the core, and note the small dab of gray silicone inside the cover that prevents the wires from shorting to it. Now remove the small wire clamp on the backside and pull back the section of black insulation that covers all the wire splices. These wires are all made of single filament epoxy coated copper, so during the entire process flex them as little as possible to prevent breakage and cracking of the insulation.

Note the wires crisscrossing between the coils First weave is done in the right direction Wind the remaining coils in an alternating fashion
Using a vise to hold the core while you are winding is a major help in keeping things neat. It will also keep movement to a minimum, protecting the leads. Just don’t crank the pressure to it and risk damaging the windings. Take a few minutes to look at the stock windings encased in epoxy. Note the wires crisscrossing between the coils. One wire leads from coil to coil, while the other returns from the last coil back to the leads. Leaving 8 inches or so at the beginning, wind your newly acquired magnet wire a couple of times around the leads to anchor it, and begin weaving it between the coils as shown. Make sure that you make that first weave in the right direction. Once you begin the winding, keep a steady tension on the wire, being careful not to actually stretch it or damage it’s insulation.

As long as your first weave is done in the right direction, one of the tricky parts is done! If you begin winding the coils in the wrong direction, no harm will be done, but the voltage produced will be subtracted by the original windings, making a brighter light than stock, but not to the full effect possible. Following the next few pictures, wind the remaining coils in an alternating fashion, the first coil being wound clockwise, the next counterclockwise, the next clockwise, and so on. I found that winding a pass up from the bottom of the coil, down to the bottom, back up, down again, up again, and then using a few turns to get down one more time made the coil about the size you want.

The voltage produced is proportional to the amount of turns you make, so don’t make too few turns, but don’t make the coil too large, as it will be hell on the regulator and you risk the coils dragging on the flywheel. Sparks are cool, but not in this case! After you have wound all of your coils, alternating the direction between each of them, weave your wire back to where you started, as shown in the picture at right. Try to hold a steady tension, as this will help things stay where you want them to be. Remember, this thing is going to take a beating, between the heat and vibration, so you want everything as solid as you can make it. Leave 8 inches or so of wire free when you are done. Take a second to look at your work. Did you alternate direction each time? Are the coils the correct size, not too small, not too big? Are there any single wires that stick out further than the rest, risking touching the flywheel? Great job, your almost done! Just think of the moths you will attract on that next night ride! More to pick from your teeth, it’s hard not to grin while riding this monster!

Remove loop that was used to anchor the wireCarefully remove the loop that you used to anchor the wire when you first started winding and twist it out of the way. Slide back the cloth insulation on the yellow/white wire and unsolder the bare wire from the insulated one. Take your wire that returns from the coils you made, and cut it to a length that will match the end of the yellow/white wire, and strip 1/8″ or so of the clear insulation from it. Remove any burrs on the end of the wire from when you cut it. Now solder it back into the connector on the yellow/white wire, making sure the connection is solid. Slide the insulation back over the joint. Your first of two connections is done! Take the wire that goes to the first coil you made and cut it to a length that matches the copper wire you removed from the yellow/white wire in the last step, and remove 1/8″ of the clear insulation. Use a mechanical connection, such as the crimp band removed from a ring connector, and place it over the ends of the wire you just stripped and the wire you removed earlier from the yellow/white wire. Solder it all together, and you are done with the electrical part of things!

For protection, put a 1 inch or so piece of heat-shrink over the mechanical connection, tuck everything together, slide the black sleeve back over the bundle of connections, being sure that all the small pieces of tubing have stayed in place over the individual connections. I found the tubing on the ignition leads needed special attention. Temporarily install the wire clamp back on. Bolt the stator and pickup back into the cover, don’t worry about torque, because it’s only temporary. Watch the routing under the stator. Check all your wires around the bundle and make sure none are touching the case, and try to separate them anywhere they are touching or really close to each other.

Aren’t those lights bright?!Now move to the connectors at the end of the harness. You want the green one and the white/yellow one. They have a clear plastic collar on them. Grab your trusty ohm meter and you should come up 1.0 ohms, plus or minus a few tenths, between them. If you have much less, or 0, you have a short somewhere or you made your tie in of the new coils wrong. If it is way high, you have an open somewhere. If the ohms are about right, temporarily install the cover and give the bike a try! With the bike running, unplug the headlight and check the voltage there. I get around 9v using a non RMS meter. An RMS type meter will give a true voltage reading, 12v or higher. Aren’t those lights bright?!

Ok, now that your done drawing every moth in the neighborhood into the garage and making the west coasters jealous of your free supply of electricity, pull the stator and clean it up nice with a good degreaser like CRC Lectra-Clean. You don’t want something that is going to remove more than just your greasy paw marks. If you use the CRC, word of advice, do it outside or you won’t even remember finishing this project, or maybe not even remember where the damn stator went anyways! ( I won’t do THAT again.) Remove the wire clamp one more time and squeeze the stator back into the vise. Remember not to crush those coils!

Work the epoxy into the windingsNow, mix up your epoxy, no rush here, the stuff has a working life of ninety minutes. Oh, and just in case Mouser ignorantly placed their sticker over the directions like they did mine, the mix ratio is three parts “A” to two parts “B”. Mix it for 15 seconds after you get a nice even gray color.

Using the supplied tongue depressor (hope it’s not used!) start slapping on the goop. Use it sparingly until you figure out the best way to do it. I found that leaving the stick flat on the coil and sliding it around the coil, as shown at left, worked well. Work the stick up and down to help drive the epoxy into the windings.

The goal with the epoxy is to seal everything as best you can. Work it around as much as you can. Cover your wires where they wrap around the original windings and where they come up to the splices as shown above right. You want to goop anything that looks like it can contact anything and vibrate.

Dab of silicone to hold wires in placeAfter you are sure everything is going to be locked in place, hang the stator someplace warm for 24 hours. Like I said, no rush. Make sure there is no epoxy on top of the coils, it will rub the flywheel. Now re-install the wire clamp and stator, again paying attention to wire routing under the stator assembly and the dab of silicone shown at left. Use a small amount of thread lock on the screws that hold it and the pulse pickup.

Now you can install the cover and be done with this business! You just saved yourself a hundred bucks and be among the proud few who can say, “Oh yeah, well I wound my own stator!”. The way I looked at it, was that I could spend the one to one-fifty and have someone else do it, or chance screwing it up and give it to them to fix anyway. So far it works, but I haven’t had much ride time with it yet. Two feet of snow doesn’t seem to yield to the heat of the Mr. Megawatt Halogens.

If you would like large versions of all the pics on this page, click here.


More XR650R electrical stuff can be found at Craig Blocks page.

If you’ve decided that you really wanted was to wind the stator on an XR80 or XR100, you’ll want to go to Peter Gailunas’ stator page.

For an XR600, go to All-Off Roads site.

If you’ve toasted the ignition on your XR, check out this page by JAW on the JustXR site.

A future project may be to put a breaker in front of the regulator. You can buy them fairly cheap at any truck stop, as most modern big trucks use them instead of fuses.

Ok, it’s been a year since I’ve done this mod to the BRP, and there have been no problems as of yet. BUT, a couple of guys have informed me that they have run into a slight snag. It seems as though Honda has thrown us a twist. Some are finding that if you do it my way, you get a parallel circuit instead of series, resulting in a low output. Just be sure to double check and get the wires right before you put the epoxy to it.

Another thing that has been brought to my attention, is the fact that it doesn’t matter which lighting coil wire you connect your new one to. Just be sure that a CW winding connects to a CCW winding, or vise-versa. Just remember that if you check the ohms of the completed coil and find it lower than what you started with, you goofed up somewhere. Thanks to those that pointed this out to me.

The mod seems to hold up to abuse. It was still working all the way up to July 26th when I had a major snafu involving a high rate of speed and a 1200lb hay bale. 2.8k to repair the bike and 140k so far to repair me. That will be another article.

Hopefully I will soon be rewinding the stator again to go with a higher capacity and dual output system.

One more thing, Ricky of Ricky Stators recommends removing the stock regulator and replacing it with a “Tympanium” 14 volt unit. Makes great sense to me. Also, he says a Banshee 30/30 bulb wired in paralell will work well. Kudos to Ricky for taking the time to email me those tips. If you blow your rig up using my directions, email him instead of me! 🙂