Introduction

Regardless of the model year--'99 to present--the Road Star is designed as a no-apologies, big, bad, boulevard cruiser. As such, the electrical charging system is made for the K.I.S.S. principle--Keep It Simple, Stupid. But this can conflict with our bike's ability to transform its character.

The installation of passing lamps, a highly popular add-on, can tax the generator to near max if your Roadie is a model year 2004 or earlier. And many owners don't stop there: GPS, radio, accent lighting, heated gloves and clothing, intercoms, and other power-hungry accessories. Let's face it. We love transforming our bikes to suit us.

The electrical draw these options demand can quickly exceed the capacity of many stock systems. If you reject the notion that "less is more," when it comes to your Road Star, a charging-system upgrade may be a necessity.

There are three, primary, options for upgrading the charging-system:

• Yamaha O.E.M. Direct replacement stator and rectifier/regulator. This upgrades earlier model bikes--1999 to 2004--to have the same capacity as the later models. It also corrects an electrical imbalance in which the rectifier/regulator can burn out, or shorten the life of some of your electrical components. Note: The above is not a misprint. The stator and rectifier capacities were not upgraded and balanced until the model-year 2005.
• ElectroSport. This option adds roughly the same capacity than those available from Yamaha.
• RM Stator. This option adds roughly the same capacity than those available from Yamaha, as near as I can tell.

In addition, there are electrics-modification companies that will rewire your stator for more capacity, and there may be some other seller of aftermarket stators and/or rec/regs I don’t know about.

I opted for the Yamaha O.E.M. direct replacement parts, as my bike is a 2003, and my electrical power needs are moderate--passing lamps, GPS, and SpeedoHealer.

Here's how I determined what I needed: Before I added my passing lamps, my battery charger would show the 'charged up', green light in less than a minute when connected to my battery. When I added my passing lamps, it took several minutes to get the green light, no matter how long or short my ride was. Now that I have upgraded my stator, I am getting the green light even quicker than ever. I have concluded from this that my electrical system was just about maxed out before I upgraded my stator--where output from the charging system was barely equal to the bike’s needs.

The owner’s manual for my bike says that my charging system, via the stator, produces 21 amps, max. So I figure that the stock Road Star electrical components must draw about 17 amps (theoretically), since my passing lamps draw a little over 4 amps***. 21 minus 4 equals 17.

***Calculation: To convert watts to amps, you use: watts divided by volts. My passing lamps are 50 watts for both. Divide this by 12 (volts), equals a little over 4 amps that the passing lamps draw.

My upgraded stator produces 31 amps (max), so I feel I have about 5 or 6 amps of surplus capacity. I know; I know: 31 amps for the new stator minus 21 amps from the stock stator should leave 10 amps of untapped power. But I want to run my electrical demands at less than 85% of my charging capacity so as to keep components from overheating and burning out prematurely. Remember, this is all based on maximum output. I've read of too many stories of owners replacing their speedo or fuel sender unit or other component (multiple times), and I feel it just might be that those sensitive components are heating up because the total electrical draw for their bike is very near the capacity of their charging and regulating system.

Tip: On my bike, I have removed some stock components, but here's the reality: My bike has LED taillight and turn signals. Also I have removed my electric fuel pump. However, the taillight saved me only about 0.5 amps, and the turn signals use a load-equalizer which nullifies any gain from using LEDs. I also figured that any electrical gain from eliminating the fuel pump would be extremely small, given how infrequently it operates.

What's your total?

Important Tip: I have listed part numbers below. However, manufacturers change them for inventory purposes, and occasionally improve parts further. Therefore, be sure to check for availability of parts with better specs than those listed below.

• Stator, Yamaha part#: 5VN-81410-01-00, or Electrosport part#: ESG752.
• Regulator/Rectifier, Yamaha part#: 5VN-81960-00-00, or Electrosport part#: ESR440. Note: If you have a chrome cover for your existing rec/reg it won't likely fit over the replacement part. The newer ones are slightly bigger.
• Stator bolts (quantity: 3). Only needed if you destroy or bung the head(s) of these stubborn items. Yamaha part#: 90149-06019-00, or any M6 x 1.00 x 19mm bolts will do.
• Silicone form-a-gasket (like Versa-Chem 273 High-Temp, Black, Silicone, Gasket Maker), available at most auto parts and home improvement stores.
• Gasket removal liquid (like Versa-Chem Gasket Remover spray), for cleaning off the old gasket remnants. Available at most auto parts and home improvement stores.
• Generator cover gasket. Yamaha part#: 5PX-15461-02-00.
• Generator cover bolt washer. Yamaha part#: 90430-06014-00, optional but recommended. This is the little washer for the lower, long bolt.
• Exhaust header gasket, for the front pipe. Use either Yamaha part#: 3EG-14613-00-00, ($3 to $6ea), or AutoZone part#: Fel-Pro 23588, (less than $1.50ea).
• Dielectric (silicone) grease, to help reduce corrosion in electrical connections, available at most auto parts and home improvement stores.

• 5mm hex wrench.
• 8mm hex wrench for Removing/installing exhaust header.
• Modest metric or SAE socket wrench set, for removing the exhaust tail-pipe, as needed.
• T-30 Torx wrench, for the stator. This is for removing the stator from the inside of the generator cover. Note: I'm told that some Road Stars have phillips screws instead of Torx.
• A piece of strong string at least 6 feet long. Alternately, you can use an electrician’s Fish Tape. Optional, if you wish to route the stator wires through the same path as stock, without major disassembly of the bike.
• Soldering pencil, if you will not be using Yamaha O.E.M. replacement parts. This is to solder connectors on to wires. Alternately, you can use crimp-on connectors.

This project can be done without draining the oil from the engine, as long as you do not upright the bike. This means: Leave the bike leaned over on its side-stand. Once the generator cover is loose, you may lose a few tablespoons of oil, but unless your bike's lean-angle has been altered by lowering the suspension or something, no significant amount should spill out.

Tip: If you have lowered your suspension, you can increase the lean-angle by putting the tires on something (very stable) roughly the same height as the amount you’ve lowered your bike. In other words, if your bike is lowered 1.5”, you can lay a short 2x8” board flat under each tire. Or you can just drain at least some of the motor oil.

Remove the seat. Disconnect the positive battery cable.

Remove the left side cover. Then remove the right side cover. Remember, the right side cover has a small flange-head bolt near the joint between the two side covers.

Next unbolt the right-side floorboard bracket. It is held on by two button-head bolts going into the frame. Be careful to support the floorboard assembly as it comes loose. This assembly is still attached by the hydraulic hose and the brake light wiring. Use a tool box or other support to lay the floorboard assembly onto.

Warning: If you just let the floorboard assembly hang by the taillight wires or hydraulic hose, you run the risk of breaking the wires loose from the brake light switch, or damaging the switch itself.

Remove the front exhaust pipe.

Now unplug the stator connector from the wiring harness. This is found behind the frame’s seat-tube, just behind the rear cylinder. See photo below.

Tip: To make it much easier to fish the new stator wires through the space between the engine and transfer case, I recommend using an old trick: Tie and tape a piece of strong string with a secure, but small knot around the stator wires at the connector. Instead of string, you could use an electrician’s ‘fish’ tape. Just be sure it is secured well to the stator wires at the connector.

Now crawl beneath the bike, and pull the stator wires down and out from the corrugated wiring harness tube. Untie your ‘fish string’ from the old stator wire, but tie the string temporarily somewhere, so it won’t get accidentally pulled it back out.

Next, unbolt the two bolts holding the generator's oil-delivery-tube into the right side of the engine. It is much easier to remove this pipe and the generator cover as a unit, rather than to try to separate them while on the engine. See photo below.

Unbolt and remove the generator cover and oil delivery pipe, as a unit. All the generator cover bolts are the same size, except two longer ones:

• The central bolt near the top
• The bolt nearest the oil delivery tube

The bolt nearest the oil delivery tube has a copper or aluminum washer. Keep track of (or replace) this washer, and where it goes.

The generator cover is magnetized to the generator rotor. To remove the cover, un-bolt it, pull or tap it free of its gasket seal, work it off its alignment dowels, and then pull the cover free with enough force to overcome the magnetic force.

Tip: Stuff a rag or rubber glove partially into the big holes at the bottom of the generator area in the engine case. This will prevent small parts like alignment dowels from 'jumping' in.

Remove, and keep track of, the two alignment dowels. They have a tendency to slip out of your hands and fall in to very frustrating places, so be careful.

If your bike is a model 2003, or earlier, I highly recommend you do the Starter Spin Fix while you have the generator exposed. See the Fixing the Starter Spin Problem article in this website for details.

Turn the generator cover upside down (resting it on some clean shop towels or other protective layer). See photo above.

Remove the single bolt for the stator wire bracket--noting how it is positioned, for reassembly referrence. Next, use your fingers to wiggle, and pull loose, the two rubber oil seals for the stator wires. See photo below.

Use a T-30 Torx wrench to remove the stator from the cover. The three bolts are on with Loctite so they may not come off easily. Tip: If you must use heat to loosen the Loctite, be careful you don’t melt any wiring coatings. You may have to replace the bolts if they don’t come out without bunging up the heads. See the Parts section for part description.

Now is a good time to clean the generator cover gasket surfaces of old gasket remnants. Do this for the gasket surface of the engine case, as well as the generator cover. Be sure to wipe up any particles that may fall in. Be sure you clean off all silicone remnants from the oil seals and cover, too.

If you separated the oil delivery pipe from the generator cover for some reason, bolt them back together. Be sure both ends of the oil delivery pipe have their O-rings installed.

Next, bolt the new stator assembly into the inside of the generator cover. Torque the torx bolts to 5.1 ft-lbs, which is 61.2 in-lbs--not too tight. Be sure to use blue Loctite on the bolt threads.

If you are installing an ElectroSport stator, you might only be able to match two of the bolt holes. I have not seen this, but I have read that it was the case, at least for earlier units from ElectroSport.

Now apply RTV (silicone) gasket maker to the two, rubber, oil seals and push them in to place. See photo above. Do not wait for the gasket maker to dry. Install the generator cover before the gasket maker has cured. The assembled cover will hold the oil seals tightly in place while the gasket maker dries.

Before installing the generator cover, re-install the stator wire bracket inside the generator cover. See prior photo above.

Insert the two alignment dowels for the generator cover into the engine case. Then slip a new gasket over the dowels.

Tip: The generator cover is magnetized to the generator rotor. As soon as you begin installing the cover, it will be sucked in by magnetic force.

Bolt and torque the generator cover on, using 7.2 ft-lbs, which is 86.4 in-lbs. The long bolt nearest the oil delivery tube has a copper or aluminum washer. I recommend you install a new washer at this point. I didn't, and it leaked.

Bolt and torque the oil-delivery-pipe back into its hole in the right-side of the engine case, using 7.2 ft-lbs of torque. Again, be sure it has its O-ring installed.

Now run the stator wires back toward the corrugated wiring harness. Tie and tape the new stator wires just like you did for the old wires. Help get the process started by pointing the connector into the corrugated tube so that it won’t get hung up within. Carefully pull the string (and new wires) up through the tube to the point of connection under the side-cover area, near the bike’s center.

If you are installing a Yamaha stator, smear some dielectric grease into the contact points of both connectors and then connect them. If you are installing an ElectroSport stator, you will have to cut the Yamaha connector from the old stator, and solder it to the new one.

Alternatively, you could cut the stator connector from the bike, and connect the new stator with the generic connectors provided with the ElectroSport stator. Then smear some dielectric grease into the contact points of both connectors and then connect them.

The photo above shows the Rectifier/Regulator on the bike, with the connector unplugged. Remove your rec/reg by unscrewing the two bolts at the sides, lifting the cover-boot up out of the way, and then unplugging the connector. See photo below.

To install your new rec-reg, just bolt it on the bike, plug in the connector by just snapping it on, and then push the cover-boot back down over the connector. Done.

Reinstall the front exhaust pipe, preferably using a new exhaust gasket.

Tip: I do not recommend torquing the exhaust header-flange nuts, as the flanges on many aftermarket exhaust systems are thinner than stock, and bend easily. Just tighten moderately. Then after your first few rides, check the nuts again.

Reinstall the right-side floorboard assembly by torquing the two button-head bolts under the floorboard assembly using 35 ft-lbs of torque.

Then just reconnect the battery, bolt the side-covers on, and snap your seat back on. That's all there is to it.

Now you’re ready to add your favorite electrical accessories, knowing you won’t come out to a dead battery—at least not because your stator couldn’t cut it. You also won't be stranded somewhere because your rec/reg got fried.

Ride on.

Questions should be asked in our forum (Use discuss link below). The forum is very active and you stand a good chance of getting your questions answered there. If you would like to leave feedback for the author, or have additional information you think will benefit others, please use the comment section at the bottom of this page.

Discuss this article on the forums. (6 posts)

DISCLAIMER: This information and procedure is provided as a courtesy and is for informational purposes only.  Neither the publishers nor the authors accept any responsibility for the accuracy, applicability, or suitability of this procedure.  You assume all risks associated with the use of this information.  NEITHER THE PUBLISHERs NOR THE AUTHORs SHALL IN ANY EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, PUNITIVE, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OF ANY NATURE ARISING OUT OF OR IN ANY WAY CONNECTED WITH THE USE OR MISUSE OF THIS INFORMATION OR LACK OF INFORMATION.  Any type of modification or service work on your motorcycle should always be performed by a professional mechanic. If performed incorrectly, this procedure may endanger the safety of you and others on your motorcycle and possibly invalidate your manufacturer’s warranty.

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