1961 Miyata Miyapet

[subrew]

I decided to start my next project, so I pulled this little beast over to the work area. It was made by the Miyata Bicycle Company, for only a year or two. I've only found some basic specs on it, saying it is a 50cc two-stroke, has a 3-speed conventional transmission (with clutch) and a 12v setup with an electric starter.

As purchased:

I spent about an hour Saturday morning doing some teardown:

Main wiring junction. This bike is very unique, in having a 12-volt system and an electric starter:

After another hour Sunday:

I wanted to see the condition of the top end on the Miyata Engine. It turns over very nicely, so I knew it wasn't frozen up. As it happens, the cylinder looks fantastic. Very clean bore, no scoring at all. And since I don't have any specs, I was curious what type of carb it runs, and what spark plug. Of course the spark plug has likely been changed, and who knows if it is the correct one. But at least I know the thread pitch and reach.

Interesting combustion chamber shape, with offset plug location:

An Amal 392 carb. I'll have to research this monster to see how big it is. PS: I don't have big hands, so you can compare the size of the inlet to my thumb in this pic:

Chris H.
http://subrewgarage.blogspot.com/

 

[swan]

Cool! I'll be watching, looks like fun.

 

[JustinLonghorn]

Yep, I am on board.

 

[subrew]

More details of this peculiar beast:

Seat pan. Not rusty, just covered in dried up old foam:

Seat pan, foam, and cover.

Expansion Chamber. Very strange, with the rear portion slipping into the main portion, and held on with a threaded rod running down the middle of it:

Rear shock disassembled:

The front shock and leading link assembly:

Stator assembly:

Instead of a flywheel rotating around the coil, the coils spin inside a stationary drum housing the magnets. Quite a bit different than other bikes of this era:

 

[stroker crazy]

Count me in - this is one interesting little beast!

Crazy

 

[subrew]

I discovered last weekend that the Miyata uses bicycle tire sizes. In this case, 22x2.25. I'll actually be swapping over to a set of 17" rims with some shorter spokes, so I can use a more standard 17" moped tire. Original tires:

I also got everything stripped and ready for primer/paint:

And the engine cleaned up:

Some paint work done, and wheels laced up:

In roller form:

A few more goodies installed:

I'll hopefully do a bit of wiring tonight, but we'll see. I may be a lazy ass.

 

[DrJ]

This thing looks great.

 

[my-79-750-k]

I'm watching this one like a hawk, this is one interesting build.

 

[HerrDeacon]

Very unique and cool, looking forward to the rest.

 

[Chucklhead05]

Very cool build. Love the 'vintage' color ya painted it. reminds me of my grandparents porch furniture.

 

[codys1024]

Very cool build. Love the 'vintage' color ya painted it. reminds me of my grandparents porch furniture.

lol good stuff

 

[milehighcj360t]

can we talk about the slew of awesome that is posted in your early pics? you've got quite the collection...

Oh, and this little bugger is turning out rather nice as well. congrats!

 

[Yamatech]

can we talk about the slew of awesome that is posted in your early pics? you've got quite the collection...

Oh, and this little bugger is turning out rather nice as well. congrats!

looks like he's got his hands full with projects. Dont be shy to send some my way if you feel the need to part ways with them haha.

 

[subrew]

I do have quite a few little dink bikes. Some or low mileage originals, some are $50 bikes that came in boxes, some or "restomod" style projects based on incomplete and tatty original bikes. I've been favoring building bikes, as opposed to restoring as of late, but this little Miyata has been fun.

Current Stable:

1966 Honda S65 - stock, original
1964 Yamaha YJ1 Riverside 55 - hot rod YSR50 engine
1964 Yamaha YG1T - stock, mild restoration
1970 Suzuki AC50 - stock, original
1964 Hodaka ACE 90 - period style hop up mods, more dirt oriented
1964 Honda C102 - stock, restored
1962 Honda Trail 55 Rat Bike - 140cc engine
1963 Honda C100 - Vintage Trials bike, S90 forks, Betor shocks, shortened frame
1964 Bridgestone S90 - cafe racer
1963 Bridgestone BS7/D - cafe racer
1966 Honda C110 - Bonneville project, completed, never made it to Boneville
1969 Kawasaki G3TR - Brat style, titties and dragon gas tank

I have a 1966 Suzuki K15 waiting in the wings, and a handful of Honda S90/CL90 parts bikes. I might build up a vintage race scrambler, and do a Hare and Hound with a local club.

 

[Yamatech]

Nice man, keep adding to the collection and someday you'll have a museum haha.

 

[barry]

Regarding the Carburettor as being a #392, let me explain that to you. Early Japanese motorcycles used many English Amal designs. They encrypted their name on many of the old carburetors using the number 392. In the older Japanese language, 3=MI, 9=KU, 2=NI. This is a Mikuni carburetor. Currently 3=SAN but back then and generations earlier 3 was MI. I have numerous old Honda's using different model carbs but with the 392 on them. Barry barrysulkn@aol.com

 

[subrew]

Interesting! So is it a Mikuni licensed from Amal? Because it clearly says "AMAL" on the carb.

 

[Rude Boy]

Sweet break down of those unique parts. cool project for sure.

 

[subrew]

A bit more progress. Including building up the seat pan with new foam. I wanted to try and use the original seat cover, just for shits. It cleaned up very nicely, and I was able to patch up a couple small tears. It still needs a little smoothing out on the sides, but seems to be getting better each day:

I also found a set of repro footpeg rubbers from a Yamaha YD1S with an almost identical pattern:

I also got the side covers installed:

I have a new petcock on order, after somehow losing the original. It likely would have needed a full rebuild anyway, but I hate losing stuff. It seems as if the threads are M16x1 and some moped and Ducati's use that pitch. One I get that, I'll throw in a new battery and see if it runs.

I'm also going to visit a chrome shop down south of me to see if I can get the exhaust and headlight ring replated.

 

[subrew]

What's that? It runs? Damn right bitches!!!!!

http://youtu.be/cbEJ3LP8lN8

New M16x1.0 Petcock and a battery gave me spark and fuel. It literally started on the third rotation, no choke needed. Didn't even have to adjust the idle speed or mixture.

Now I just need to make a list of all the little things, like re-chroming the exhaust, making new Miyata script badges etc. Lots of little details.

ps: I was apparently in 2nd gear, not having a clue which direction to kick for first. It isn't quite that gutless.