Seth’s Shindengen SH847 Series Regulator Rectifier (R/R) Installation on a Honda Pacific Coast PC800

This page describes installation of a Shindengen SH847 series regulator/rectifier (R/R) on a 1997 Honda Pacific Coast (PC800). Results of various tests performed after installation are included.

Editor’s Note: The following information comes entirely from fellow PCer Seth. He did excellent research and produced a wonderful writeup of how to install a series regulator rectifier (R/R) on a Honda Pacific Coast.


This page describes installation of a Shindengen SH847 series regulator/rectifier (R/R) on a 1997 Honda Pacific Coast (PC800). Results of various tests performed after installation are included.

The R/R performs two functions: it rectifies the three-phase AC output from the stator to provide DC and it regulates the output to avoid overcharging the battery. The stock regulator is a shunt design which operates by short circuiting the stator windings when the battery is fully charged. The excess power is dissipated as heat by the R/R. The SH847 is a series regulator and operates by disconnecting the stator windings when the battery is fully charged.

Note: The SH847 isn’t cheap. Towing a trailer over The Mighty Mac up to The Very Boring Rally in Duluth, MN, without a charging system makes it seem worthwhile.


Having replaced all of the lights on Winglet, a 1997 Honda Pacific Coast (PC800), with LEDs there is plenty of power available for farkles: driving lights, heated lederhosen, Bushtec trailer, … . That is not what Mother Honda had in mind when the charging system was designed. The LED conversion greatly reduces the electrical load and shifts more responsibility to the regulator.

The stock R/R and, to a lesser extent, the stator are considered (by owners) to be consumable parts. The first is rather easily replaced. The second involves opening the crankcase and is, at best, a nuisance. (Been there, done both repeatedly, didn’t get the shirt. At least the engine doesn’t need to be removed from the frame like ‘oldWing’s.)

The series R/R design allows the stator voltage to rise, but reduces the load and the heat produced by the stator. High voltage is related to insulation breakdown, but so is elevated temperature. In my judgement the voltage (About 70VAC open cicuit, IIRC.) is not sufficient to significantly shorten the life of the stator and the lower temperature should increase the life. (Then there is thermal cycling causing physical damage to the stator and … .)

The plan is that this should be the last R/R and stator that Winglet needs. (This is what authors call “foreshadowing”.)

The Beast

It’s big, but fear not. There is a splendid place to hide it if you haven’t tucked an air horn or other farkle in the right fairing protector. It mounts securely to the frame within the structure of the fairing protector, though it does not use the frame as a heatsink. The weathertight connectors face aft to reduce exposure to road spray. Engine heat and exhaust from the radiator ductwork are not problematic. Ideally the cooling fins would be oriented from front to back to provide better airflow, but there isn’t sufficient space to rotate the R/R with the connectors and cables attached.

Tip: Click on any image to open a larger version in a new browser tab.

Fabricated mounting bracket, SH847 R/R and Honda R/R.


Despite considerable hunting, I have not been able to find a comprehensive specification sheet for the SH847 from Shindengen. The following specifications have been cobbled together, but are certainly not guaranteed.

Width120mm100mm between mounting hole centers.
Length135mmPlus mating connectors and minimum bending radius for wires.
Thickness40mmAbout 1 9/16″.
Current30AAverage @ 40°C (104°F) with no airflow.
37AWith 1 m/s (2 1/4 mph) airflow.
Peak Current50APC800 alternator maximum output is 360W or about 30A.
ProtectionVoltage & Temperature 


Sources of supply are shown, but feel free to shop around.

  • Shindengen SH847 Series R/R kit from RoadsterCycle. Tell Jack you desire the following:
    • SH847 Super Kit
    • Battery Wire Add On: extra 1 foot (extends DC leads from 36 to 48 inches)
    • Stator Wire Add On: 48 inches total (extends AC leads from 12 to 48 inches)
    • Request that the battery and stator leads be supplied unterminated.
      (The circuit breaker and rings terminals for the battery leads will be supplied with the kit.
      You will need to cut the wires to length and terminate them during installation.)
  • 1″ x 1″ x 1/16″ aluminum angle 4 3/4″ long.
    McMaster-Carr p/n 8982K39, 1 foot long.
  • 3/4″ pipe hangers, quantity 2.
    McMaster-Carr p/n 3006T87.
  • Various 6.0 x 1.0mm bolts and nuts.
    Excess length is not your friend. Nylon-insert lock nuts are a good thing.
  • Honda stator male connector.
    I happened to have one with pigtails sitting on a shelf. Possible sources with no guarantees:
    ElectroSport sells a mating pair that looks correct as “ES115 3-pin OLD STYLE Connector Set 1/4″”.
    Cycle Terminal sells a mating pair that looks correct as “Set SC250-3”. (Sumitomo Connector, 0.250 inch contact width, 3 poles.)
  • Braided expandable tubing.
    Tidies up the installation and protects the wires from abrasion.
    McMaster-Carr p/n 9284K612 (1/4″) will accommodate both the DC (2 conductors) and AC (3 conductors) wires.
    255°F rating with good resistance to hydrocarbons and oils.
  • Adhesive-lined heat shrink tubing.
    Prevents the braided expandable tubing from slipping and fraying.
    Without the adhesive lining heat shrink can easily slip off the braided tubing.
    Mouser Electronics p/n 517-EPS3003/848CLRBK 3M® p/n EPS300-3/8-48″-Clear 3/8″ inch expanded, clear, 3:1 shrink ratio, 230°F rating.
  • Miscellaneous consumables: tie wraps, DeoxIT® grease, …


  1. Cut the angle stock to length. Do not extend the length beyond that needed to support the R/R from edge to edge.
  2. Mark and drill the angle stock for the R/R.
  3. Notch the angle stock for the pipe hangers.
    metal nibbler is a handy tool for notching the stock. The 1/16″ you save will be nice to have later.
  4. Mark and drill the angle stock for the pipe hangers.


Note that installation of the SH847 leaves the original R/R and wiring in place. You can disconnect the SH847 and reconnect the stock R/R if there is some reason to do so, e.g. the frame is cold.

NB: Do NOT run the engine with both R/Rs connected to the battery at the same time.
You don’t want to find out if the overvoltage protection circuits in the two regulators get into an argument.
I don’t think they will, but with the price of Magic Smoke these days … .

  1. Remove the right Fairing Protectors (#7), left and right Air Duct/Maintenance Lids (#10) and left and right Side Covers (#11) as explained in Chapter 2 of the Honda PC800 Pacific Coast Service Manual. (Numbers refer to parts on Page 2-2 of the Service Manual. Subsequent pages in Chapter 2 provide details for removal/replacement of the various bits.)
R/R mounting location inside the right fairing protector.
  1. Mount the SH847 to the angle stock and tighten the bolts.
  2. Install pipe hangers on angle stock, but do not tighten the bolts.
  3. Install assembly on engine protector tube and tighten all hardware.
    (Okay, you might want to peek at the next step before you tighten down the pipe hanger bolts.)
Mounted R/R.
  1. Check clearance between R/R and crankcase.
    Look straight back from the front and confirm that there is clearance between the R/R and crankcase.
    Reposition the pipe hangers as needed to maximize the clearance.
  1. Unplug the original R/R connector(s), wrap with electrical tape and secure.
    (1989 PCs have separate AC and DC connectors at the R/R.)
  2. Unplug the original stator connector, wrap with electrical tape and secure.
  3. Remove the circuit breaker and jackets from the supplied SH847 wiring harnesses.
    The positive conductor (red) has a ring terminal connected to the circuit breaker.
  4. Connect the AC and DC wiring harnesses to the R/R.
R/R connectors viewed from rear looking forward.
  1. Route the DC wires (red/black) to the battery and the AC wires (3 yellows) to the stator connector.
    Keep in mind that there is limited space between the frame and Tupperware when everything is reassembled.
    Cut the wires to length (leaving enough extra length to terminate the wires) and remove the wiring harnesses.
Cable routing: stator (yellow arrow) and battery (green arrow).
Old (yellow arrow) and new (green arrow) stator connectors.
Circuit breaker adjacent to battery.
  1. Add the braided expandable tubing to the wire bundles and heat shrink tubing to the ends of the braided tubing.
  • Cut two lengths of heat shrink tubing and slip them over the braided tubing before running the wires through the braided tubing.
  • The braided tubing gets shorter as it is expanded to fit over the wires. Run the wires through the braided tubing before cutting the tubing to length.
  • Depending on the cable routing you may not be able to pass the stator connector through the chosen path, hence the recommendation to terminate the stator cable after adding the braided tubing and reinstalling the cable harness.
  1. Apply DeoxIT® grease to the R/R contacts and install the AC wiring harness.
    Attach the male stator connector to the wiring harness.
    Apply DeoxIT® grease to the contacts and mate the stator connectors.
  2. Apply DeoxIT® grease to the R/R contacts and install the DC wiring harness.
    Attach the ring terminals to the wiring harness and connect the circuit breaker to the positive (red) conductor.
  3. Connect the positive (red) and negative (black) ring terminals to the battery.
    Note: Do NOT reverse the polarity! Momentary contact is all it takes to brick the SH847.
    Aside: There is some rational to always connecting the battery ground, negative (black) on a PC, last and removing it first when fiddling with battery connections. With the ground connected you can accidentally short the positive terminal to the frame and other bits and pieces while fiddling about. With the ground disconnected the only place you can short the positive terminal to is the negative terminal.

Testing and Results

Winglet was ridden with various electrical loads. It didn’t matter. The new R/R became lukewarm at most, but never hot. The stock R/R would have removed fingerprints in an instant.

The minimum load was without any accessories and all of the lights replaced with LEDs. With the stock R/R this would result in the maximum amount of current being shunted and thus the maximum heat generated. Aside: At idle with stock lamps and the brake lights on the battery would have been discharging. With LEDs that is not the case.

The following measurements were made with the ignition on and the engine not running. (For perspective, the stock headlight bulb draws 4.9A/5.4A.)

StateTotal LoadNote
Headlight and running lights.1.91A 
+ Driving lights on high.2.84ADenali D2 LEDs.
+ Brake lights.3.35A 

Maximum load was with a heated vest (about 45W), driving lights, Bushtec trailer and various minor accessories. (All of the trailer lights have been replaced with LEDs with the exception of the license plate lamp. It has wires soldered to the bulb and the bulb is glued in place!) Engine temperature was allowed to rise sufficiently to turn on the cooling fan.

Mann Tracht, Un Gott Lacht

The misfortune that followed provided an opportunity. Not long after installing the new R/R the Rick’s Motorsport Electrics stator installed about 15 years earlier developed a short to ground. (The original stator lasted about 8 years.) An ElectroSport stator was purchased and the experiment was planned. Various resources on the Internet suggested that a shunt regulator reduces the load on the stator when it shorts the windings. (Did you know the word “gullible” isn’t in the dictionary?) It seemed like a good time to get some objective data on stator temperatures under various conditions using shunt and series regulators.

Possibly applicable reading: Facts about shunt-based regulators.

Possibly applicable viewing: “Turbo Encabulator” the Original.


First, do no harm. I know that the stator is an unhealthy place with hot engine oil, hotter windings and machinery with a low tolerance for loose bits bobbing around. All of the materials going into that environment had to tolerate chemicals and heat. As a SWAG I chose 200°C (392°F) as a target temperature limit. The materials I obtained I dubbed close enough:

  • RTD: 1112°F, glass coated platinum element. “Capable of withstanding extreme environmental conditions.”
  • Conformal coating: Constant service temperature 320°F.
  • Wire: 28 AWG, PTFE insulation, 392°F.
  • Heat shrink tubing: PTFE, 500°F operating, 620°F shrinking.
  • RTV: Silicone, neutral cure, non-corrosive, 399°F.

Did you catch it? I didn’t. I soldered the wires to the RTD with an 800°F tip in the soldering station. Applied the conformal coating and allowed it to cure. Put the heat shrink tubing on and cranked up the Milwaukee hair dryer to shrink it … . Shrink temperature 620°F. 60/40 Sn-Pb solder melts at 370°F. D’oh! A little creative rearranging and I managed to get the solder to do its thing while the tubing shrank. (“Hats back on gentlemen, an idiot!”)

Aside: While taking soldering/brazing/welding classes I caused some confusion when I used the Milwaukee variable temperature heat gun to sweat solder 3/4″ copper pipe and fittings together.

A Littelfuse PPG102A6 Resistance Temperature Detector (RTD) was embedded between poles of the stator prior to installation. A Fluke 87 Multimeter was used in Min/Max/Avg record mode to capture the temperatures.

Wired Resistance Temperature Detector (RTD) with the stator.
Resistance Temperature Detector (RTD) between stator poles.

The wires were slipped through the jacket that protects the stator wires. Rather than make changes to the crankcase cover or seals I simply ran the wires out between the cover gasket and the cable seals. A generous dab of Permatex® Ultra Black® gasket maker is working nicely.

Resistance Temperature Detector (RTD) wires leaving the crankcase.
Test ride with Fluke 87 Multimeter.

Shunt vs. Series Regulator Test Results

At idle the series regulator supplied <= 3.75A.

Started the engine and allowed it to idle until the fan cycled on and off. 72.6°F ambient temprature, 71°F stator before starting.

  • The first test was run on battery only to establish a base temperature for the crankcase.
    The battery was recharged after the first test.
  • The second test was run with the shunt regulator to give it the benefit of a cooler initial temperature.
  • The third test was run with the series regulator.
 No RegulatorShunt RegulatorSeries RegulatorDelta (Shunt – Series)
Fan start:136°F198°F170°F-28°F
Fan stop:139°F200°F171°F-29°F

The engine was then run at higher speed (~3K) and the maximum temperature noted:

Shunt RegulatorSeries RegulatorDelta (Shunt – Series)

Additional tests were run during sustained operation at highway speed.

  • 63°F ambient temperature, the fan did not operate.
  • The battery was fully charged prior to starting and recharged during several miles of riding.
  • Data collection was started after riding several miles at highway speed.
  • A Fluke 87 DMM captured maximum, minimum and average values at 100ms sample time.
  • The sampling was stopped prior to exiting the highway and the recorded data was saved while safely parked.

The first test was run with the shunt regulator to give it the benefit of a cooler initial temperature. The second test was run with the series regulator.

 Shunt RegulatorSeries RegulatorDelta (Shunt – Series)

Conclusion: The series regulator lowers the stator temperature under all of the test conditions.

Honda Pacific Coast PC800 3D printed mirrors

Here’s an option to replace broken mirrors on a Honda Pacific Coast PC800 motorcycle. Because the mirrors are no longer offered by the manufacturer, there are only a couple solutions to a damaged mirror. You can buy one off eBay or a similar site for a lot of money (as of April 2021, I’ve seen a set of mirrors sell for $500). You can contact Alex in Russia to have him resin cast new mirror plastic parts for you. Or you can contact Ruud De Greef via Facebook to buy 3D models of the PC800 mirrors and 3D print your own.

This post shows some of the info that I’ve pulled off of Facebook from Ruud De Greef. The original post is here.

I have no experience with the 3D printing files and I do not know if they are any good or not. If you buy the files from Ruud and they work well or they do not work well, please let me know so I can update this post.

Note that it appears only some of the parts are available for 3D printing so you’ll still need some parts harvested from your busted mirror.

Some people in the comments on the Facebook post mentioned that there were 3D STL files available several years back but I haven’t been able to find the files yet. I’m not sure if Ruud’s files are from the old STL files that a few have mentioned or if they’re created from scratch.

Here is something about the challenges of 3D printing old bike parts:

Here is an old Reddit post that mentions someone at some point was 3D printing parts for the PC800. I haven’t been able to find any other information besides this:

I have the mirrors from the PC800 transformed in a digital format. You can now print your mirrors yourself. The costs are 120 dollars for all files (see photos). IMPORTANT: you don’t get a real product ..only the files for your printer! Please send me a PM if interested. Printer volume needed: 200 x 200 x 250mm

Ruud De Greef
16 hours print, Pet-G material, 0.4 mm nozzle,, 0.15 layer height.. just out of the printer, no sanding, just removing the breakaway support structure (2 minutes of work). BASF Ultrafuse ABS Fusion+ – Ruud De Greef

Laser Exhaust for the Honda Pacific Coast PC800

A very interesting exhaust system manufactured by Laser showed up recently on a Netherlands-based website as they parted out a PC800. A PCer in The Netherlands bought the parts and has installed them on his PC. I’ve collected what information I can about this exhaust. If you know anything else about it, please get in touch with me.

Based on the photos from the parts dealer, this exhaust fits into the same location as the stock PC800 exhaust. The muffler is in the stock location (no second muffler on the opposite side).

Here is the part number on the stainless steel exhaust. It seems to say:

BSAU 193 T2
e4 89/235-890

Here is a still from a short video of the exhaust system in place on the bike. You can see it bolts to the stock location. Video is below. You can hear a short clip of it revving.

The most interesting thing to me is this exhaust collector/resonator. It looks like a piece of art.

The muffler has the appropriate mounting tab to mount to the stock exhaust location on the PC.

This is a collection of photos of the two exhaust headers that sold with the rest of the exhaust parts from the PC that the parts dealer parted out. I’m not sure if these are special or different from what comes stock on a PC or if they’re the factory exhaust headers. My guess is they’re probably stock and not special.

Here is the sales literature for the exhaust. It’s from Jama Originals. Over the stock bike, the exhaust does slightly improve performance on the dyno according to this graphic.

Here is a photo of most of the parts that came out of the collection of exhaust parts that the bike breaker sold to the PCer in The Netherlands.

The OEM part numbers involved are as follows. I am not sure of the part numbers from the aftermarket company other than what’s written above.

18231MR5000 – for muffler

18320MR5003 – exhaust pipe

18392MK4000 – exhaust pipe

18320MR5003 – exhaust pipe part 2

18300MR5870 – exhaust silencer


A Laser exhaust recently (July 2021) was posted for sale on a Dutch website. I grabbed a few photos of it and have added them below.