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¯\_(ツ)_/¯ UltraDork
3/26/18 7:45 a.m.

I have been chipping away at this thing so I should probably make a thread about it.  

A while ago, Ian F asked me if I had any interest in an old bike- of course I did.  Then when I found out what exactly it was, I had LOTS of interest in an old bike- the H1 is the stuff of legends, and while slow by modern standards, with early 70s brakes and suspension it was a bike too fast for its' own good.  This particular example was parked in the back of his mom's garage, and hasn't moved under its' own power since before I was born.  Ian may have a picture from the process of acquiring it, this is the only image I have of it before I started disassembly:  

The day I got it home, I assessed the situation- every cable is frozen, every piece of rubber dry rotted, the wiring is questionable, and the engine a complete unknown but with less than 5000 miles on the odometer I was hopeful.

¯\_(ツ)_/¯ UltraDork
3/26/18 8:05 a.m.

So I kicked things off by pulling the tank, carbs, spark plugs, and headers, and spraying fogging oil into the cylinders every weekend for a month.  I didn't want to spin the engine with any crud bound up in there, for fear of hurting something, so the bike looked like this for a while:  

Eventually the oil dripping out of the exhaust and intake ports started looking nice and clean, so I decided to kick it over and it spins nicely and makes "bloop" noises indicative of having at least some compression.  One of the cool things about 2 strokes is that you can see the pistons and rings through the ports, and they all look pretty good:  

If I want to try running the engine, I need fuel and spark, so I started by taking the carbs slightly apart.  The middle cylinder's carb represents a milestone in that it's the first time I've ever had dust come out of a carburetor:  

I'm soaking them in a pretty nasty ATF/acetone mix since all of the little brass bits are REALLY stuck and I don't want to ruin them when I try to take them out:  

For chasing down the spark, this awesome 70s service manual was included with the bike:  

I'm going to try to use the manual as much as possible, and the internet as little as possible, because I've never done that before and it sounds interesting.  The bike has no battery, and while it is kickstart only it probably still needs some amount of juice the produce a spark.  The positive battery cable is missing, but the manual says that brown wires are positive so I made a little jumper wire with a bullet connector and used some jumper cables and a spare car battery to give it power:  

Seems to be sort of working:  

Looks like the distributor cap and rotor aren't too happy:  

Per the resistance, voltage, and amperage tests in the manual, basically every component of the ignition system appears to be dead.  I can hear capacitors humming and it gets 12V in the places it should but that's about it- I'll need to spend some time checking over the harness since it appears the ignition switch was deleted at some point so who knows if everything is getting the appropriate signals.  I can buy a new harness if I need to but I'd like to determine what exactly has happened to this one first. 

And that brings us to present day!  If you know anything about these bikes feel free to chime in, it's not the first time I've tried to revive a motorcycle from the dead but it is definitely the oldest.

¯\_(ツ)_/¯ UltraDork
3/26/18 8:09 a.m.

I guess I should state what the plan is for this thing- I want to get it running and rideable.  Anything that's completely wiped out will be replaced with something slightly better than original parts, but I want to keep the look and feel of the thing as original as I reasonably can.  I'm starting by trying to get the engine running primarily to find out whether it will require a complete teardown or not, and will then move onto the chassis, suspension, and brakes.

Basically, at the end of this I want to find out what scared the crap out of people back in the early 70s devil  

Lof8 GRM+ Memberand Dork
3/26/18 8:25 a.m.

Very cool!  I'm in to follow the progress.

Mezzanine Dork
3/26/18 8:57 a.m.

H1! Power band from god, frame made of paper towel tubes.


I had one of these death machines years ago - they're amazing. I have no suggestions to add because you're already doing all the things. Keep doing the things.

Woody GRM+ Memberand MegaDork
3/26/18 9:34 a.m.

My friend's dad has/has one of those when we were growing up, and I think he bought it new. It is the single loudest motorcycle that I have ever heard.

Be careful with that thing. They are more dangerous than normal motorcycles.

adam525i GRM+ Memberand Reader
3/26/18 1:01 p.m.

I built a model of this exact bike as a kid from a kit my dad had saved, same colour and everything. He and my uncle had these when they were new, my uncle's only lasted a few weeks before it was written off and replaced with something else but my dads survived and was replaced by a 750 when they came out.

Good luck getting it going!


Ian F
Ian F MegaDork
3/26/18 1:38 p.m.

I'm still amazed after 40+ years of sitting, the tubes in the tires held air when we pumped them up.

¯\_(ツ)_/¯ UltraDork
3/26/18 1:46 p.m.

In reply to Ian F :

Not only that, they are still currently holding that air- I'm not sure if it's a lack of heat cycling and UV exposure, or a case of "they don't make 'em like they used to" but it's impressive.

Robbie GRM+ Memberand PowerDork
3/26/18 2:27 p.m.

So awesome.

Cotton PowerDork
3/26/18 2:59 p.m.

Oh man,  I love those bikes!

Woody GRM+ Memberand MegaDork
3/26/18 3:51 p.m.

Middle cylinder on my neighbor's always ran hot.

stuart in mn
stuart in mn UltimaDork
3/26/18 6:24 p.m.

My understanding is the CD ignition box (boxes) can suddenly up and die without warning, that could be your problem with sparks.

There is pretty fair support for the H1, both from places that deal in NOS parts as well as aftermarket parts suppliers.  If you can find a copy of Motorcycle Classics magazine there are ads for some of those places in the back pages.

I have the older uncle to that bike...a 1968 Kawasaki W2SS.  Rather than being a two stroke triple it's a 650cc vertical twin, a kinda sorta copy of an early 1960s BSA.  It actually shares a few components with the H1 - the wheels are the same, along with some other minor bits and pieces.

Your bike looks like it will clean up well.

Petrolburner Dork
3/26/18 7:12 p.m.

That thing is going to sound so sweet.  It's hard to beat the sound of a 2 stroke triple.  I've had a couple of them in snowmobiles but never a motorcycle.  

¯\_(ツ)_/¯ UltraDork
4/1/18 3:34 p.m.

Working my way through the ignition system, I've found a few broken wires and I think I'm missing the entire coil assembly.  The stator/pickup side of things also doesn't look great, there are missing screws and broken/frayed wires:  

The good news is that this is probably what stopped the bike from running a few decades ago- the bad news is that stock ignition system parts are obscenely expensive, and the only well reviewed aftermarket systems are intended for racing and don't have the ability to run lights.  More research is required.

Trans_Maro PowerDork
4/1/18 3:50 p.m.

FYI, multi-cylinder two strokes will have crank seals between the cylinders which are probably dried out by now.

If you get it running but it insists on running like crap, you may need to do a full teardown to get them replaced.

¯\_(ツ)_/¯ UltraDork
4/1/18 6:07 p.m.

In reply to Trans_Maro :

Thanks for the tip- I just want to see if I can at least get it to sputter to life, and will assess the situation from there.  I won't be surprised if it requires a complete rebuild, but the need to see if it will run with just some fiddling is too strong.

mikedd969 New Reader
4/5/18 5:17 p.m.

Very cool find!!! I can't remember the last time I saw one of those on the road.  

I rode one, once and only once, a long time ago, sometime in early to mid 80's.  It was absolutely terrifying, no joke, scared me half to death.  I'm no stranger to fast motorcycles, but one ride on that thing was all I wanted.  smiley

Ian F
Ian F MegaDork
4/5/18 5:42 p.m.

In reply to ¯\_(ツ)_/¯ :

Who knows what George did to the ignition system. Being an electronics engineer, one can assume he was the last person to have all that open before you. Add in a driving ego that assumed he knew better than the engineers who designed the bike (possibly combined with alcohol, lack of money and unreliable parts sources), and I can imagine all sorts of "creative" changes were made.  As my mother mentioned, he didn't really talk to her much about the bike. Even less (none at all) to me.

I wonder if you could get MegaJolt to work?

8valve Reader
4/5/18 6:49 p.m.

Looks like you have a very nice complete one.  My buddy has rebuilt some of these.. if any Q's I can ask.

¯\_(ツ)_/¯ UltraDork
4/5/18 7:07 p.m.

From what I've been able to gather, what we're looking at in that last picture is some sort of attempt to replace the signal generator pickup and rotor with... something not stock.  I think if I can source a good pickup and rotor I should be able to repair the rest of the CDI system as normal.

SaltyDog Reader
4/5/18 7:16 p.m.

Love these bikes.

As Mezzanine said, the scary part is the sudden, narrow power band and flimsy frames.

We called them Flexy Fliers back in the day.

I posted a pic of my old H2 in the Pics of your bike thread.


I'll take a look in the archives and see if I still have any manuals that might help you. If so, I'll happily send them your way.

Trans_Maro PowerDork
4/6/18 7:46 p.m.

A couple of the guys I ride with are Kawasaki weirdos. One of them has an H1 and I rode it once. Feels like there's a hinge in the middle.

That being said, Z1 enterprises is your friend in this matter: https://www.z1enterprises.com/

I'm 100% sure you can just find some good used parts to put the factory system back in and it will work just fine.

Don't go looking for trouble, those engineers were pretty good at what they did.

SaltyDog Reader
4/6/18 7:57 p.m.
Trans_Maro said:

A couple of the guys I ride with are Kawasaki weirdos. One of them has an H1 and I rode it once. Feels like there's a hinge in the middle.

That being said, Z1 enterprises is your friend in this matter: https://www.z1enterprises.com/

I'm 100% sure you can just find some good used parts to put the factory system back in and it will work just fine.

Don't go looking for trouble, those engineers were pretty good at what they did.

Agreed. particularly with the ignition. I was trying to spend money with Paul Gast, who was the authority on these things at that time and he said that the factory stuff was pretty fantastic, so why bother with anything else?

¯\_(ツ)_/¯ UltraDork
4/8/18 6:28 p.m.

While I wait for some guy on the other side of the country to harvest some ignition system parts for me, I figured I might as well get the fuel system in order.  The acetone/ATF bath did a good job loosening things up, so I took each carb apart and cleaned things, replacing gaskets and jets:  

and setting the float heights- these brass floats are delicate:  

Well that was tedious:  

Three times as tedious:  

In order to get the slides off the bike I needed to free the throttle cable.  The throttle assembly was pretty gunked up with old grease and came with pre-stripped hardware:  

I had to drill the screws out, so I need to find replacements.  With the slides free and the crazy 1-into-3 octopus cables removed I then rebuilt that end of things:  

Assembling these onto the carb while keeping the cable and gasket and needle all lined up is a real bastard, but by the third one I was pretty decent at it:  

Then I did the same for the silly 1-into-3 petcock:  

In theory, all I need to do is clean the fuel tank and run lines to have a fully functional fuel system!  Everything was in pretty good shape, just obviously old and rubber parts were brittle.  Hopefully this bodes well for other parts of the bike which are yet to be explored.

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