1971 Honda SL90K K1 #01

Candy Emerald Green / White

SL90K-201353

Completed January 04, 2012

This is a very unique bike here in the states.  This is a 1971 Honda SL90K Japanese Domestic, which simply means that it was a non-export model sold in Japan.  Apparently they needed a model with less cc's or less horsepower to meet regulations and they built this off of the SL100 platform.  I only know of a very few of these that exist these days and this one only showed 41 kilometers on the odometer when I got it.  It was hard to believe the mileage until we disassembled the engine and found virtually no wear on the cylinder / piston.  It did have a completed wasted cam journal and that may have been its' demise back in the day and that may have been why it was preserved. 

Unique items include; black frame instead of the traditional silver for the Honda Motosport bikes, center stand, buddy pegs, upswept muffler, smaller carburetor, different air intake boot to mate to carburetor, crossbar handlebars, addition of a tachometer, uses an SL125 headlight bucket to accept the two cables for the instruments, turn signals, unique LH switch assembly to accommodate the turn signal switch, helmet holder, SL90 side cover badges, seat cover much like an SL100 K0, but with a buddy strap, buddy peg perches welded to swingarm, unique routing of the coil wire, license bracket assembly made to hold Japanese license plate, non adjustable headlight (side to side), front headlight ears made to accept turn signals, wiring harness made to accommodate turn signals, bridge rectifier and 6v turn signal flasher, reflective tape stripe on front fender and all decals in Japanese writing.  Brochure pages below.

With the rarity of this bike I thought it deserved some professional pictures and those are next, followed by my normal ones by the pool.

             

                      

                     

 

My 'normal' pictures follow here......................

Unique reflective tape stripe on front fender.

Non U.S. non-adjustable headlamp & front turn signals.

Headlight ears made to accommodate the front turn signals.

The SL90K has a much smaller bore carburetor than the U.S. spec 100's

Badges that I had reproduced.

Two-up saddle with grab strap.

Upswept muffler to clear the buddy pegs.

Buddy peg mounts welded to the swingarm.

Rear turn signals mounted to the upper shock bolts.

Non U.S. spec taillight lens with orange reflectors on the sides.

Unique license bracket with different spacing for license plate holes.

This is how it bolts to the bracket.

Speedometer reading in km/h.

Unique switch with turn signal provision but the lever perch is separate.  Honda CL's and CB's had turn signals, but the lever perch's were built into the switch and they used different levers.

Bike came with a center stand where the U.S. spec bikes did not.

Another shot of the license bracket.

Bike came with a helmet holder where U.S. spec bikes did not.  Reproduced helmet holder sticker in Japanese writing.

Tire pressure warning sticker reproduced in Japanese writing.

Reproduced battery caution label in Japanese.

Good shot of the center stand mount.

Another shot of the smaller carburetor.  Presumably the smaller bore altered the H.P. for different licensing restrictions.

Grab strap mounting hardware.

The headlight bucket on this model had to be like the one for an SL125 with the cutouts for the two instrument cables.

v

Identification sticker reproduced with Japanese writing.

Close up shot of the reflective tape on front fender.

 

Assembly & Original Pictures Follow:

 

Day 1 Assembly started December 26 2011.

Even this Air Cleaner to Carb boot is unique as it has to neck down to the smaller carburetor throat.

Day 2 Assembly started December 27 2011 - Up on 2 wheels.

Day 3 - Going together with motivation

I'm using a set of original Honda levers with the clear coat still intact.  Been saving these for a long while for a worthwhile project.

Special derby cover with cutout for checking timing without getting oil all over the place.

IV Fuel bottle hooked up and engine is ready to fire.

This is the unique license bracket with a much narrower spread for the plate than the U.S. model.

Tire Pressure Decal - Reproduced with Japanese characters

Battery overflow hose routing - In Japanese

Helmet holder - In Japanese

Reflective tape on the leading edge of the front fender.  Picture of original laying on tire.

Two up seat with grab strap.

Center Stand in place

This is the unique reflective stripe on the leading edge of the front fender

End of Day 3

Side Cover Badges (Finally arrived - Thanks to my reproduction guy)

Completed 01/04/2012

 

 

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Original Pictures Follow:

I'm looking forward to starting....and finishing this project.  This is a Japanese Domestic SL90K.  Apparently there was a cc limit for certain ages in Japan and they made a 90cc version of the U.S. spec SL100.  This bike is not to be confused with the U.S. SL90 made in 1969 that was the first to be introduced Honda Motosport lineup.  Completely different bikes.  The SL90K's had a centerstand, turnsignals, reflective tape on the front fender, upswept exhaust to make room for the rear buddy pegs and a seat that resembled the SL100 K0, but with a buddy strap.  As you can see, this model has differences from the SL90K K0 model in that this one has a black frame, crossbar handlebars and the addition of a tachomter along with the speedometer.  You will also notice that all the decals are in Japanese writing throughout the bike.  The odometer on this bike shows 41KM.  Not sure how it got into the shape it is in, but will see when it gets torn down.

This is how I found the bike with the ratty seat etc, but it does run well.  The strange part is that the speedometer shows only 40 Kilometers, but parts of the bike sure don't represent that low number......however, look at the front tire which appears to be original.  The mudflaps on the bike are not factory original, but the little reflective tape on the leading edge of the front fender is.

Here you see the crossbar handlebars and tachometer which the U.S. Spec SL100 did not have.

Here is one of the unique stickers with Japanese writing.  This is located up near the steering neck.

Here is a good shot of the upswept muffler which allows for the passenger pegs.  The mounts for the passenger pegs are welded to the swingarm.

Here is a shot at the original tire which also shows very minimal wear, but realistically.......maybe more than 40 kilcks.

I'm not 100% sure, but many of the Japanese scooters I've seen had the yellow reflectors built into the taillight like this one and this lens is in really nice shape.

The license bracket portion of the taillight assembly is bolted together instead of being welded like the U.S. counterparts.  The distance between the license plate holes is also different.

The seat has the grab strap and you can see the mount for the rear turnsignals which are missing from this bike.

The seat is styled after the SL100 K0 with different pattern from the SL100 K1. 

Unique to this bike is the turn signal switch incorporated into the horn button assembly.

Notice the absence of the on/off/on switch on the RH switch making both this and the LH switches unique to the Japanese Domestic machines.

Here is that speedometer that I've been talking about.  "W" Stands for Winkers.

Bike perched on the centerstand.

The rear sprocket on this bike looks larger than any I've ever encountered which also leads to some of the mystery as to why someone would change that out, add the mudflaps, remove the turn signals and then only ride a few kilometers.

I am currently having these badges remade.

Here is a good shot of where the reflective tape is on the front fender.

This is the non U.S. spec headlight or "bugeye" which is non adjustable from left to right as was necessary for the U.S. version of the SL100.

The headlight ears are cut to accommodate the turnsignals.

Turn signal mount on the LH side.

The engine number is on a sticker instead of being engraved in the engine cover.

Chainguard decal showing the tire pressure for 1 up and 2 up riding.

Welded on rear footpegs mounts.

Helmet Holder decal.

Footpeg mount welded to the swingarm.

The license plate bracket is a two piece item.  Looks like they took the U.S. spec model and just chopped it off.  The distance between the holes for the license plate is different for the Japanese tag.

Battery hose routing decal.

Placement of the Battery hose routing decal.

Placement of the flasher for the signals.  Glad that this was on the bike since the signals were missing.

Much different wiring than the U.S. spec model.  Assuming that is a different version of a selenium rectifier.

Probably not the original tool kit..............but a nice one.

Lots of parts to collect and will get started on this one.  Documented that they came in Candy Emerald Green, Candy Ruby Red and Candy Sapphire Blue.

 

DISASSEMBLY COMPLETE - November 2011

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