1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

I've just received a 1978 Honda PA50 II from my stepfather, he's had it for quite some time, and it's not been used since he bought it in '97. Being a tech guy, I figure I can learn how to fix the thing, get it on the road, and tool 'round town in the thing.

So, one of the main questions I have, is how to start this thing -- How do I start this thing? I haven't done this, in case there is sand or metal shavings in the fuel-line. I'm about to go and get fluids to clean out the engine, and put the fuel mix together.

There are plenty of docs for modding, and fixing, but none with basic practices!

Re: 1978 Honda PA50 II resurrection -- howto?

If the bike is complete, there's a key ignition switch and a key.. turn that switch on. (otherwise remove the headlight and hotwire it)

set the Kill switch on the right grip to "run"

Engage the lever at the rear left wheel so the pedals spin the drive belt.. (the drive belt is on the left side.. Disengage this lever to pedal it like a bicycle)

Reach down and move the choke lever on the carburetor forward to close the choke. Got gas? Needs 2-stroke oil so use a 32/1 mixture.. Turn on the petcock at the gas tank so gas is flowing.

Pedal hard while opening the throttle a bit.. After it starts and runs for a minute, push the choke back (open).

Assuming you got lucky, vrrrooom.. away you go..

Re: 1978 Honda PA50 II resurrection -- howto?

I'd recommend an inline fuel filter as well, cheap, and can save you the headache of cleaning the carb.

Re: 1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

Thanks for the tips. Should I drain the gas tank and clean it first, or just let 'er rip?

I've attached a picture of the unit.


Re: 1978 Honda PA50 II resurrection -- howto?

well, it depends on how much faith you have.. stopping problems before they start is nice if it's possible.

I found that exact same bike at a wrecker a couple weeks ago and been working on it ever since.

As is usual for me i wanted to inspect everything. I took off the wheels to change a tire but also to check the brakes (and the rusted brake drums needed help).

I also pulled the head off to see the condition of the piston and cylinder.. guess what.. i found some rocky dirt in there.. someone musta pulled the plug and somehow kicked dirt into the combustion chamber.. glad i didn't just start it up.

My tank had been Kreemed so i pulled the petcock to look for rust.. the fuel filter in there was OK as was the screen tube. However, after a little running, i had idle/low speed running problems. The tank's cap was Kreemed too (oops) and so the tank vent was clogged.

Another other fuel/idle problem was leaks around several old dried O-rings and all the joints between the carb and reed block and cylinder were questionable. A coating of Permatex 2 (non-hardening) fixed this.

So, if i were you, i'd check things out before heading out.

Re: 1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

I've attached a picture of the engine from the front. It's all rusty. Of course, I understand that it's the inside that needs to not be all rusty. I'll have a friend of mine look at it this evening, and keep you guys posted. Thanks for the suggestions, I'm sure my buddy will take me to get a spark plug. Also, where do I get replacement screws? Home Depot? Looks like they're original, and rusted into oxidized metal foam.


Re: 1978 Honda PA50 II resurrection -- howto?

yeah.. your bike has been outside in a damp climate for a while. I would plan on replacing a lot of screws and bolts. Home Depot doesn't have a great selection of metrics but you'll find the smaller ones there.. If you have a Orchard Supply nearby you might have better luck.

Replacing the some of the phillips head screws with allen heads might be a good idea. Phillips heads are useless and strip easily when rusted. Allens can be cranked down without stripping.

The head and cylinder can be sandblasted and they will look good as new.. the iron cylinder can be painted with any hi-temp paint.

Be careful when compressing rings to replace the cylinder.. Rings are the hard, brittle kind of cast iron and will snap in two if you jam one. I'm running only the one top ring for this reason, but it runs fine. Racers run one ring deliberately for less friction. New rings are probably available at Honda.

Also be careful when torquing down the head bolts (and everything else) .. these small bolts and nuts dont need a lot. Plan on finding rusty and corroded stuff all over this bike and they will snap off easily.. Buy a inch-pound torque wrench and some WD-40.

Re: 1978 Honda PA50 II resurrection -- howto?

_Thanks for the tips. Should I drain the gas tank and clean it first, or just let

Re: 1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

Any idea what kind of screws this thing uses? They're pretty badly rusted, very unidentifiable. I'm gonna go get a gas can today, and some 2-stroke oil.

Re: 1978 Honda PA50 II resurrection -- howto?

All the screws, nuts and bolts are metric.

You can pick up a metric thread pitch identifier tool at any hardware store. There is also a guage available for both diameter and pitch.

Take it easy when you start it up.. listen closely for clanking metal or scraping noises.. if you hear anything, check it out.

a couple ideas

I'd take a wire brush and WD40 to the wheels and other chrome. Then wax it with some Mothers Wax.

With a few hours work, you can get it looking really nice.

Definitely drain the old gas. I second the advice about the inline fuel filter.

I'd give the carb a good cleaning too. Search the forums here for messages from Fred about his trick for getting to the carb. It's kind of a pain, but you have to do it.

Good luck.

Re: 1978 Honda PA50 II resurrection -- howto?

Copy of the manual at this addy...


Sturdy bike, known in Europe as the Camino, designs have been copied by many other manufacturers. Good luck!

Re: 1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

You guys have been great, and I learned alot durring the resurrection procedure. Also, thanks for the URL for the manual, helps quite a bit when trying to figure out how to fix this thing, and get the right stuff. Apparently, this thing was riden a few times, and then just left on the side of someone's house for 10 years. Asside from damage from rain, and lack of use, this thing is in mint condition, and everything works.

Only problem with this thing now, is the rust, and the bent front wheel.

Friend of mine suggested fine steel wool (instead of wire brush) to take-off the rust, and MY GOD does that make rust go away! brush lightly, and voila! Icky brown rust goes bye-bye! Amazing!

Amazingly, I was able to get it started without changing the 10-year-old gas. I pedaled my face off, but got it to run, and idle.

When we flushed-out the icky brown sludge-like gasoline, we put the petcock back in, and that broke-up the icky chunks covering the hole. Plenty of fuel flushed the rest of the icky chunks out, and the fuel system is now clean.

Next job is to unbend the front wheel (or replace?), and to put some sort of anti-rust paint on there.

So, two questions:

[] How do I unbend the wheel? It's definately round, but warped. I've never done this.

[] Which paint should I buy? The thing is yellow from the factory, but there are like 4 shades of yellow paint at the auto-place near me, I'm thinking school-bus yellow, or sun yellow, but just not sure.

Again, folks, thanks for the help, I'm excited to ride this thing 'round the SoSide of Pittsburgh, but still gotta get a plate for it.

Re: 1978 Honda PA50 II resurrection -- howto?

assuming it's a spoked wheel, the proceedure is a part of the process called wheel truing.

Out of roundness is cured by loosening a few spokes on the wider sides and tightening the ones on the narrow sides.. This squishes the wheel into a rounder shape.

This will likely make the wheel wobble side to side and that has to be fixed by =loosening spokes attached to one side of the hub while tightening the ones on the other.

It might take a couple hours to get the wheel round without a wobble in it if this is the first time you played with spokes.

If the rim has dings where someone slammed into a concrete curb, you can hammer on on the rim to take dings out. Low speed bikes can tolerate a few mild dings without being dangerous to ride on.

Here's a link to everything you need to know about truing wheels.


Re: 1978 Honda PA50 II resurrection -- howto?

_Out of roundness is cured by loosening a few spokes on the wider sides and tightening the ones on the narrow sides.. This squishes the wheel into a rounder shape_

well.. i was close.. actually it's:

Out of roundness is cured by loosening a few spokes on the narrow sides and then tightening the ones on the wider sides.

Re: 1978 Honda PA50 II resurrection -- howto?

Drew From Zhrodague /

I did some of this, to no avail. Stripped one of the things, and the wheel was still lumpy. I jumped up and down on it against a concrete step, turning it a bit each time to get the thing straight, and that has the greatest effect. I don't weigh much, and I tried to be nice to the thing while doing it.

This week, I tried to wire-brush the rust off the ancient fender, and was making some headway getting the blistered paint off, when one of the guys that works at the business downstairs from me produced at rotating wire-brush kit for a drill. This made excellent work of the rust, and the blisters.

Then I primed and painted the thing. Still needs more school-bus yellow paint on it, and I didn't do such a good job with the priming/sanding aspect -- the rust blisters are still visible. At least the color will be consistant. I'm excited about that at least.

I've also steel-wooled all of the chrome, and most of the paint with icky rust goop, and grime. This makes the color stand out a bit more, and makes it look more spiffy. I understand why people have full-on motorcycles, and I should take better care of my Subaru.

Thing kicks over after a while, but I think it's not getting enough air -- once it gets warm, it won't stay running for long. Part throttle gets it to limp but it will die at anything above that, and idle makes it stop after a while. I figure that either something's clogging the intake, or something is clogging the exhaust.

I've driven it 'round the neighborhood a little, past the harley bars. I've heard people pointing at the silly contraption, me peddling like an idiot to keep the engine running! I don't care, it's neat!

Can't wait to get a plate, and commute to my future job downtown, 'bout 2-3 miles away. Wonder where I can park this thing. I figure just chain it to a mailbox, or something...

Re: 1978 Honda PA50 II resurrection -- howto?

It will be even 'neater" when you don't have to pedal to keep the engine running.

You may have an intake restriction of some sort, perhaps just a dirty intake filter. The filter's removal point is near the front of the drive belt. You'll see a small black plactic rectangle held in by a piece of wire . Move the wire down and pull the long filter holder out. Wash the foam filter, dry it, and soak it with 90 weight gear oil and squeeze out the excess and reinstall it.

The muffler could be clogged with carbon. Instructions for cleaning it out are in "Fred's Guide" in the articles section of this site.

But there are other things that cause generally poor running. One is vacuum leaks somewhere in the fuel intake path. Any leak here will upset the fuel/air mix and will cause anything from mild to severe running problems. Old gaskets and O-rings dry out and shrink and therefore leak.

There is no shortcut to resurrecting an old moped. The entire bike needs to be examined, repaired and cleaned (carburetor _must_ be immaculate) where needed.

As far as cosmetics, i bought an automotive detailing book that covers restoration of everything from paint to chrome to rubber to leather and the information has saved me a lot of time.

Re: 1978 Honda PA50 II resurrection -- howto?

Your air filter might have completely degraded... I had a small bit of foam left when I bought my pa50, but it's quite easy to make a new one, just find some comprable foam and cut it to fit, and oil it as mentioned.

As for parking it, just turn it up and chain to a bike rack or something... if you have a lot of bike thieves around, I'd recommend using a couple of locks.

If you haven't already, you should clean the carb, it's a bit of pain with the pa50, but it's worth it.

Re: 1978 Honda PA50 II resurrection -- howto?

I may as well repeat the procedure i use for getting the carb out.

The engine hangs by a single large front pivot bolt. If you remove that bolt and raise the center stand, the engine/swing-arm drops to the ground. (bang! so be careful and support it and lower it slowly ) The bike will barely balance upright on the muffler, but it's stable enough to take a screwdriver to the 4 reed-valve screws. Now you can remove the carb/intake manifold as a unit.

First you must detach any cables, wires, lines that might get pulled too far when dropping the engine. Detach all that stuff.

When you put it back together, raise the engine first. Secure it with that long bolt.

Then re-rout the cables and wires so they won't interfere with dropping the engine the next time. Some, like the throttle cable and decompression cable must by detached every time, but many others can be routed round obstacles and this makes the job of getting to the carb much faster and easier.

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