20 mph Honda PA50-II

ItsLookingUp /

I have a 1983 Honda PA50-II with stock CDI. I have heard that Honda made a model that was geared to a maximum of 20 mph. Can anyone verify that, or is it rumor? If it is true, my guess is that it has a different final reduction gear at the rear wheel. How can I identify a 20 mph model if it does exist? I've got the ped up to 18 mph. Every part that could be effecting the speed has been rebuilt or replaced. The list of parts which have been put into this ped now exceeds $700.00 so I'm not quitting now.

Re: 20 mph Honda PA50-II

ItsLookingUp wrote:


> I have a 1983 Honda PA50-II with stock CDI. I have heard that

> Honda made a model that was geared to a maximum of 20 mph.

> Can anyone verify that, or is it rumor? If it is true, my

> guess is that it has a different final reduction gear at the

> rear wheel. How can I identify a 20 mph model if it does

> exist? I've got the ped up to 18 mph. Every part that could

> be effecting the speed has been rebuilt or replaced. The list

> of parts which have been put into this ped now exceeds

> $700.00 so I'm not quitting now.

Well I'm not the PA50 expert around here, I've just spent a lot of time working on mine in the last couple months.

There were versions of the PA50 the I and the II. I believe 1979 was the last year they made the 20 mph model (the I). You can confirm that you have a II by looking just above the VIN sticker on the front of your bike behind the forks.

Here's my suggestion for you. Post a list of all that you've done here. Also go through Fred's guide in the resources section, and we'll go from there. Mine would only do about 25 mph when I first got it. Now I easily do 37 mph.

I posted a list of stuff I've done to mine yesterday. I also forgot to add that I put on a new drive belt. That made a huge difference.

Good luck, and we'll get you up and running soon.

Re: 20 mph Honda PA50-II

ItsLookingUp /

Thanks for the support. That's what keeps this bike from ending up next to the "parts ped" (an extra '81 Vespa Ciao; engine runs sweet but the frame is broken). I'm trying take 5 ped's out of retirement for the kids (and parents) of the neighborhood. Like Wayne, I'm quietly building a division. My primary motivation is to give the neighborhood kids (13 - 16 years old) a focal point. Most of the kids are finishing up their baseball season. Currently, there are 3 boys who own their own mopeds, in my driveway daily wanting to go "riding," and another four that their parents allow them to ride but they don't own their own ped... hence the Lexington Transportation Battalion (LTB).

The LTB has 4 loaner mopeds in different states of readiness:

'02 Tomas Revival (If I want to ride, It's not a loaner)

'85 Tomos Silver Bullet

'96 Manet/Puch Maxi

'83 Honda PA50-II

The Revival was purchased new, Thursday (Jun 20) and already has 148 miles on it.

The Silver Bullet was purchased late May in Cinn. OH from an 18 year old about to leave for Marine boot camp. It is the fastest ped with a bi-turbo exhaust. It can't be ridden at night. It was bought with a distroyed magneto. We are trying to convert it to a CDI. But, we don't know how to prevent blowing lamps.

The Manet/Puch was also purchased in Cinn. OH in late May. It was purchased as a running bike and is reliable. It needs things like a non-spit gas cap, a rear brake cable and turn signals. All parts have been ordered.

The Honda was purchased in northern Indiana in early June as a non-running bike. The trip to northern Indiana was to pick up a beautiful '81 Ciao and the seller said "hey, I've got another ped in the garage if you would be interested in two." My goal is seven, so I bought it!!!

That's the background on the Battalion. I will detail the repairs/renewals done to the Honda in a new thread.

I hope I can count on the other Divisions. You can count on us mobilizing to protect the southern flank if needed.

Re: 20 mph Honda PA50-II

So... When are you going to answer the question I asked about ..'How wide your belt is?'... (measure it)

I have a PA50I... they only did 21mph stock... but they were NOT restricted by gearing to do so... just by the way the motor was tuned..... after all... mine does 37mph now ... and the only 'gearing' change was the variator notches.

(and remember... at 18.... you are not far off from the 21mph they did stock)

I'm sorry... but these questions of ..'it runs... but it doesn't quite run right'... are just soooo hard to do over the internet... its about impossible for me to help.

... Poor communications always gets in the way.

I know you've done a lot of stuff to it... and it all sounded good to me.... so I just don't know.

$700 ???... wow... I have a grand total of less than $50 into mine (sorry)... and thats mostly an ignition switch and rear tire.

I'm impressed by your willingness to conquer it.

Your bike probably really just needs a good mechanic.

(see another post shortly about PA gearing)

Re: 20 mph Honda PA50-II

ItsLookingUp /

My new belt is 19/32" which isn't a lot more than the belt I took off. I also pulled the carb and verified the emultion tube was unobstructed. It has to be the variator system that is not working correctly. As I said before, the engine is tuned beautifully. The bike has a strong take-off an revs to a high whine. The front variator isn't closing very much. Therefore, the belt isn't dropping down the rear pulley. I have replaced the starting clutch shoes and the clutch shoes. The roller weights and end caps are new. The ramp plate does show some wear but nothing irregular that might be causing the rollers to stick. The rear pulley is tight but can be opened with a screwdriver. I am mounting the new belt on the front pulley and pulling the rear wheel back until I have 2 mm gap between the belt and the outside of the rear pulley, as the manual instructs. The bike has a good mechanic... what it needs is someone who is familar with the normal operation of the variator system. Never having seen a properly working system I can't judge whether the pulleys are operating correctly. I realize the board has an even bigger disadvantage because they can't see what this system is doing. The local honda service center claims they don't have anyone on staff that has ever worked on a PA50-II.

I am going to continue to persue the variator system as the problem.

Re: 20 mph Honda PA50-II

OK... well then there is this.. I think there IS a gearing difference between the I's and II's... it is the amount of 'ramp' on that ramp plate.

I don't have the II ramp plate in front of me to confirm this... but from what I've seen and done... they are different.

(I should know for sure when that ebay motor gets here!)

and... I made changes to my motor before I ever messed with the variator... so its possible (and likely).. that the I ramp plate does lower the speed compared to the one from the II.. (at the same RPM).

soooo... lets say that somebody put a I ramp plate on your II before you bought it ?

that is about the only logical conclusion to your situation that I can see.

One way to tell ??... We both measure the ramp 'displacement' and compare.

I just did mine... lay the bare ramp plate on a flat surface... take two measurements...

... the height of the bottom of the tip of the ramp from the surface .

... and the height of the inside of the center of the ramp plate from the surface.

mine are

.... 7/32nds.. (tip)


.... 5/16ths... center.. (actually .321")

So if I am right and the two ramps are different... but yours measures the same as mine... then you have a I ramp plate on a II.

Re: 20 mph Honda PA50-II

ItsLookingUp /

That is a good idea Fred. The ped is put up for the night, but I will remove the ramp plate and measure it tomorrow. When GK told me the 20 mph model was a PA50-I, I began thinking the same thing. When I bought the bike all the roller weight caps were broken so I purchased new roller weights and caps for the '83 PA50-II and installed them into the ramp plate. The rear pulley is very difficult to open and it is a lot of work, rocking the belt back and forth in order to get 2mm of the pulley showing and it makes the belt very tight. It seems overly tight, enough that it could cause excessive wear on the bearings. I look forward to measuring the plate and getting back to you. What state are you in?

Re: 20 mph Honda PA50-II

yeah... thats one other thing about the PA's... most belt drive systems (like snowmobiles) are not adjustable... because people can easily screw it up ... and the pulleys are designed to operate on fixed centers.

I have never had a manual.. so I have always just 'winged it'... and adjusted to what I thought was right.

I have also experimented... and tried it tighter and looser... and too tight will definitely take the top speed way down..

sooo.. you might also try that... just adjust the pulleys for a looser belt... and see what happens.

Re: 20 mph Honda PA50-II

ItsLookingUp /

I don't get any more top end with a loose belt, just more vibration. The bike takes off really strong whether the belt is loose or tight. My main observation is the front pulley barely closes, even if the belt is loose. Changing the ramp plate would be the easiest way for Honda to make a slower model. I think my first challange is to service the front pulley to insure it is ramping up correctly. The other half of the problem is making sure the rear pulley isn't too stiff to open. I think my problem is a combination. Having never worked on a properly working system, like you, I'm going on what "seems right." Thanks for your patience. I will post the ramp plate measurements by 6:00 EST tomorrow. I've read your other post, was I suppose to measure anything other than the new belt width?

Re: 20 mph Honda PA50-II

I live 40 miles NW of Detroit.

Measurements?.. nothing else... but try this....

... to see how far your belt is getting up the pulley... I just went out and used a set of old style calipers (similar to a compass).. and measured the burnished marks on the front pulley ... my belt has been running at a max diameter of about .. 2 15/16ths.

This is kind of hard to measure...because the line where the burnishing 'stops' isn't exact... but some careful eyeballing will get it.

If you are getting a lot less.. then we know that is the problem... (and I would bet the problem is that back pulley... take it completely apart and clean and lube it)

Now here is something you can do for me.... (actually .. us ) >>

I am trying to determine if the rear wheel drive unit of the I's and II's are any different..

soooo.... I need you to do this small test.

Its simple.....

> put the bike on the stand... remove the belt cover... rotate the rear wheel so the tire valve is at the bottom.

Then.. place a piece of tape... on the rear variator pulley at the top.. (or?)..

Then... rotate the R wheel one full turn... and count revolutions of the tape... then report that number.

I have done it already.

If you do it ... we can have more info on PA parts.

Re: 20 mph Honda PA50-II

ItsLookingUp /

Sorry about not posting last night... I spent the night in the emergency room with a friend. Anyway, here is what I found:

The burnished marks are up to a maximum diameter of 2 5/8".

One revolution of the rear wheel resulted in the rear variator doing 12 1/2 revolutions.

My ramp plate tip is 3/8" and the center is 7/16", these measurements were taken with the three ramp plate bushings removed.

My local Honda dealer confirmed that the '82 and '83 PA50-II had a design top speed of 30 mph.

I sounds like our ramp plates are different. I decided to replace the rear pulley. The bike has set for several years and I can't get the rear pulley working smoothly. (It's only money and not as satifying as a fast ped!!!)

Re: 20 mph Honda PA50-II

Interesting..... since my I also does 12.5 turns (so does Chris R's II)... I'd say we know now that the R wheel drive units are all the same... I was somewhat hoping they were different... So I would have a choice for a gearing change.

The ramp plates sound different too... but we may be measuring them differently.

...I thought the center measurement would be the same... and the tips different.

... but it sounds like they are both diff.. ????... hmmmm

I will compare the II plate when it gets here shortly.

annnd... it sounds like you are not getting movement on the front pulley... 2 5/8ths vs 2 15/16ths.... so that's gonna reduce yout top speed.

Imagine if we could get movement all the way up the pulley face... we'd be doing 50 or 60 or something.

I hope your replacement pulley does the trick... I am amazed they still have that stuff in stock.!

Re: 20 mph Honda PA50-II

ItsLookingUp /

I'm interested to here your comparision of the new engine to your 1. I believe we are measuring the same. You instuctions are clear and not ambiguous. The new rear pulley will be in on Friday. I believe it is sticking and under pressure it sticks harder. I hoping that is a major reason the belt can't ride up the front pulley.

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