Just joined the Moped Army - tons a first timer questions

Hi All,

I just purchased a 1979 Puch Magnum II and wanted to create a thread to ask many questions I have as a new owner. I've read several of the wikis and also watched many youtube videos, but I've still got a bunch of new questions as a new rider/owner. I would appreciate any and all feedback on the below:

1) Rich/Lean: I'm having a really hard time figuring this out. I've attached a picture or the plug if that helps.

2) Oil on Spark Plug: I'm noticing oil around the spark plug. Is this normal?

3) Adjusting the throttle: I've noticed that sometimes pulling all the way on the throttle is actually less gas than twisting it ~85% of the way, is there a method to adjust this?

4) Springs for Brakes / throttle: the brake can be a bit sticky where the brake levers stick a bit after I've released them (same thing for the throttle). How can I increase the tension on these?

5) Choke: I have ta 1/14/164 bing Carb, and am unsure how to use the choke. The engine doesn't seem to idle well with the choke pushed all the way down. Where should this choke slide be positioned for typical riding and how is it used? (note: I edited this post to add this last question)

Thank you(edited)

image1.jpeg

Re: Just joined the Moped Army - tons a first timer questions

Lotsa Puch guys here to help ya out soon. Plug looks either brand new or lean.

Re: Just joined the Moped Army - tons a first timer questions

Nice looking bike.

1) Looks lean or dry (less oil in the premix) in my opinion. If you are not mixing sufficient oil to the fuel it can look leaner than it is, but I still think you are a bit lean.

2) Oil around the plug is from it weeping, that temp gauge pickup has work hardened and is not working as a good seal anymore.

3) Check your cable, no throttle the slide should be really close to closed (but not quite closed maybe 1mm-ish lifted from the floor) and wide open should be with the bottom of the slide level to the roof of the carb bore. Any higher will cause turbulence above the main jet and can cause stumbling at WOT

4) lube the cables well, same for the controls. If there is too much slop before the brakes even work then adjust by oozing the knarp and pull through more cable then tight it again, use the cable adjusters to fine tune. On the throttle use the adjuster to fine tune if there is slack in the carb cable, but only if there is slack. If there is binding, lube where it needs or replace the cable.

5) Unless it is close to winter, your choke should only be for just getting the cold engine to catch and run. On a two stroke if the choke is needed for an extended period there is something not correct and you need to do a tune up o the engine.

Hope some of that helps

Re: Just joined the Moped Army - tons a first timer questions

Thanks already for the help here a few follow up questions on these same points.

1) Im using a ration of 50:1 is this incorrect? Current jet is a 62, I could up this to say a 68 if you all think that’s advisable.

2) Very interested in learning more about this. Essentially your saying that the temp gauge (copper ring) has been harder and not there’s a small leak? Is this an issue?

3) I understand what you’re saying about the position of the slide, but how can I tell how the slide is positioned within the carb?

4) sounds like I should possible just look into getting new cables here.

5) Can you clarify - does this mean the choke “rod” should be pushed all the way down?

Sorry for all the silly questions. I’ve enjoyed learning this far here - it will take me sometime to get up to speed.

Re: Just joined the Moped Army - tons a first timer questions

Overpriced Parts /

Looks like you got a magnum mkll not magnum II

Choke slide needs to be clipped into lever/rod or it will fall down and bike won’t idle,

You push rod down to start cold, most all puchs with bing carbs after they sit enough to get cold like overnight for a few hours and still need the choke for a second or two.

The rod comes up when you turn throttle and after that you sill may need to pull by hand last 1/16 of if it sticks/stays down a bit,

You only need to have choke down for a few seconds after start then rev throttle to pull up,

Start when hot by full open throttle and release

Full throttle pull on some stock throttles can be 21mm if carb is only 14mm and idle screws adjusted for 2 mm open then throttle only will have to pull 12mm so only turning 1/2-3/4 the way,

Ya you could be lean at 62jet similar setups I run with performance pipe go 68 to 72 but make sure you have a 14mm intake,

Here is my 2 speed magnum that has stock cylinder most parts and pipe,

If your magnum don’t run somewhere close to the magnum in this crappy video,

Your bike actually should pull and be faster than one in video considering you have an expensive pipe and or maybe a kit on your bike, mine don’t (and it was hard for me to have a good run holding a old crap phone with one hand and riding one handed) then if not then your magnum MKII is not running good add or running right,

Mine starts easy too when cold basically one or two kicks with the choke on just for a second then soon as it comes to life I blip the throttle releasing/pulling the choke up,

Re: Just joined the Moped Army - tons a first timer questions

Got it. I believe I understand the choke now - thank you.

Also agree that it’s a MK II - sorry I did not mean to cause confusion.

I’ll intend to upset around a 70 jet.

For the weeping (oil around the spark plug), should I be concerned there? Is there a need or way to fix that?

Also for the intake, how can I check if it’s 14mm? Can I just measure the opening there? Is there a method that doesn’t require dismounting the carb?

Re: Just joined the Moped Army - tons a first timer questions

♣Slew Foot♣ /

Please drive across the United States in a snowstorm...

Sorry inside joke...

Welcome aboard my name is Slew Foot and I have a problem it's mopeds I thought this was mopeds anonymous...

Re: Just joined the Moped Army - tons a first timer questions

You may be able to anneal the copper lead. Get it glowing bright with a torch then quickly dip it in water. Might melt some insulation or solder tho.

Re: Just joined the Moped Army - tons a first timer questions

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

OP said....

3) Adjusting the throttle: I've noticed that sometimes pulling all the way on the throttle is actually less gas than twisting it ~85% of the way, is there a method to adjust this?

This soulds like you’re describing a lean bog. I’d try a larger jet.

Re: Just joined the Moped Army - tons a first timer questions

Lots of goodly help for you so I will just get on the #3

Remove the carb or have someone help if you don't want to disturb it. Twist the throttle to 1/2 travel and look inside the carb bore, the bottom of the slide should be 1/2 up... etc...

ALSO

There are no silly questions, you are learning, everyone needs to learn things somehow, soon enough you are going to be the guy kicking in suggestions for new folks.

> Jordan Carter Wrote:

> -------------------------------------------------------

> Thanks already for the help here a few follow up questions on these same

> points.

>

> 3) I understand what you’re saying about the position of the slide, but

> how can I tell how the slide is positioned within the carb?

>

> Sorry for all the silly questions. I’ve enjoyed learning this far here -

> it will take me sometime to get up to speed.

Re: Just joined the Moped Army - tons a first timer questions

The crush washer on the spark plug should be removed if you are using a temp gauge.

To do a reading of the plug the portion we are looking at wont tell you much. Basically if you look all the way down into the inside it should be a tan/milk chocolate color, black is rich and white is lean. Doing a plug chop is a fine way to tune, but I don't ever do it. I just start with a fat jet and work my way down then dial in the needle after.

Rich sounds like it is under water, the sound it makes is called four stroking. It is actually taking 2 full rotations of the crank to expel the fuel charge in the combustion chamber.

For the brakes it looks like you could use some new brake shoes, I would get a new set of cables while youre at ir. Also make sure the pivot points arent binding and the springs are intact.

The choke on a bing is for cold starts. You push it down, start the bike and when you twist the throttle it comes up and should stay up.

Re: Just joined the Moped Army - tons a first timer questions

Actually if the plug is white not with the chocolate Daniel above mentioned and this bike was kitted and has an aftermarket exhaust your first order of business is finding out if there is an air leak. That isn't necessarily a beginner step and I would hope somebody relatively nearby who is good at Puch mopeds would help you. It's always a problem on a bike with a previous owner who has modded the bike. If I say bought a puch from Ken roff I would know it was lovingly put together.

The worst is that there is a air leak that you don't understand yet and I go blasting around and seize an otherwise great engine because of the air leak. When I see a white plug , if it has been run ..it says I AM LEAN. .. AND and if the jetting range is reasonable then it says ..I have an air leak.

Maybe I would pm Ken roff with all that's on the bike and get advice from him.

Re: Just joined the Moped Army - tons a first timer questions

Thanks - great to see such an active community.

I’ve changed the jet to a 68. I also have a 72 if you all think that’s a better starting point.

I also notice that the although the bike runs fine and seems to idle fine, it will stalk on be when I stop and then slowly accelerate. Any thoughts here?

Also as for adjusting the throttle cable, I’ve got no issue taking the carb part, but can I just look at the slide without it fully assembled? Is that an accurate interpretation of how it will be positioned when assembled?

For air leaks I’ve tried the carb cleaning spray method. The engine does fully cutoff when I spray near the top of the carb (the part held down with two screws). I’d assume this indicates a leak, but I’ve already swapped out the gasket and not even have two gaskets sitting there and have truly tightened those two screws. Thoughts?

Re: Just joined the Moped Army - tons a first timer questions

Bings always leak from the top and 99.9% of the time from the clamp. In a 14 Bing typically youre gonna be in the 70s range, I would start with your largest jet and go down. A white plug doesnt mean air leak that is dumb as fuck. If it is stalling as you come to a stop it could be a clutch problem?

Re: Just joined the Moped Army - tons a first timer questions

I didn't say it means. I said it suggests.

Re: Just joined the Moped Army - tons a first timer questions

Great info, so I just changed the transmission oil, so I am guessing the stalling when accelerating from a stop is due to a clutch issue. Is it slipping? I'm assuming that's the issue.

I used 10W-40 Mobile 1 high mileage synthetic, but that was clearning the wrong choice. Any suggestions on how correct that? What oil is recommended, should I just stick with a typical ATF?

Re: Just joined the Moped Army - tons a first timer questions

Overpriced Parts /

> Jordan Carter Wrote:

> -------------------------------------------------------

> Great info, so I just changed the transmission oil, so I am guessing the

> stalling when accelerating from a stop is due to a clutch issue. Is it

> slipping? I'm assuming that's the issue.

>

> I used 10W-40 Mobile 1 high mileage synthetic, but that was clearning

> the wrong choice. Any suggestions on how correct that? What oil is

> recommended, should I just stick with a typical ATF?

No that oil would be fine but only for very hot weather you want it to slip not to grab at stop and it may slip too much when cold but it won’t hurt anything ,

I use 0w20-5w20 and 5w30 but only fill it to it comes out of the weep hole screw on sidecover about 9 ounces,

You’re probably stalling because you can’t idle because you don’t have your carb turned correctly and or not timed correctly but who knows,

The clutch lever is only for starting the engine the rest is automatic,

Yeah I think you’re getting off the path what’s the matter with your bike and you need to ride a good running bike to tell the difference and or find out someone who has bikes in your area to help you out,

Re: Just joined the Moped Army - tons a first timer questions

The bikes continued to drive with improved performance. I certainly don't feel a need to ride anyone else's bike, I'm just enjoying getting my bike in full working order.

Re: Just joined the Moped Army - tons a first timer questions

Always a good policy - don't ride others and don't let others ride yours (except for ones intended as loan rides) same as girlfriends / boyfriends / wife / husband / partners...

> Jordan Carter Wrote:

> -------------------------------------------------------

> The bikes continued to drive with improved performance. I certainly

> don't feel a need to ride anyone else's bike, I'm just enjoying getting

> my bike in full working order.

Re: Just joined the Moped Army - tons a first timer questions

Remove the temp gauge pickup then the plug compression seal. run the pick up between the compression seal and the plug. I had the same issue and fixed by doing this.

Re: Just joined the Moped Army - tons a first timer questions

Alright so I'm back with a few follow up questions. The bike is running great with the exception of starting acceleration after I've come to a stop. The bike basically sputters out.

As I mentioned earlier I changes to the transmission oil, so I think that's to blame. The oil that was in there was almost like liquid clay - super thick and opaque. I first swapped it with 10W-40, and had the stalling issue I mentioned. I then tried some ATF (also listed as CVT fluid) and still have the same issue. I suppose the next steps is to just try generic Type F oil, or are there other suggestions here?

Separately, but possibly related, the bike will shut off on me when stopped if idle for more than 1 minute, any thoughts on this?

Re: Just joined the Moped Army - tons a first timer questions

Brandon Weiss (Detective brandon to you) /

> Overpriced Parts Wrote:

> -------------------------------------------------------

> > Jordan Carter Wrote:

>

> > -------------------------------------------------------

>

> > Great info, so I just changed the transmission oil, so I am guessing

> the

>

> > stalling when accelerating from a stop is due to a clutch issue. Is it

>

> > slipping? I'm assuming that's the issue.

>

> >

>

> > I used 10W-40 Mobile 1 high mileage synthetic, but that was clearning

>

> > the wrong choice. Any suggestions on how correct that? What oil is

>

> > recommended, should I just stick with a typical ATF?

>

> No that oil would be fine but only for very hot weather you want it to

> o slip not to grab at stop and it may slip too much when cold but it

> won’t hurt anything ,

>

> I use 0w20-5w20 and 5w30 but only fill it to it comes out of the weep

> hole screw on sidecover about 9 ounces,

>

> You’re probably stalling because you can’t idle because you don’t have

> e your carb turned correctly and or not timed correctly but who knows,

>

> The clutch lever is only for starting the engine the rest is automatic,

>

> Yeah I think you’re getting off the path what’s the matter with your

> r bike and you need to ride a good running bike to tell the difference

> and or find out someone who has bikes in your area to help you out,

9 ounces? Every e50 ive ever had only held 5.75-6 ounces

Re: Just joined the Moped Army - tons a first timer questions

Might be a ZA50 based on the wheels and model number, hard to say with that picture and the aftermarket color scheme, could be either one. Post a pic of the other side of the bike or let us know if you're running a one speed or 2 speed motor.

I don't think your acceleration problems are due to your transmission fluid. That and your lack of idle once warmed up points to poor carb tuning or air leaks usually. You're leaving the choke OFF right? (pull tab is all the way up, not pressed in?) Have you adjusted your idle screw on the carb in at all? If you can get it to idle you can at least check for basic airleaks

Re: Just joined the Moped Army - tons a first timer questions

It’s a ZA50 (two speed).

It’s possible I’m running a bit lean. I’ve adjusted the idle screw to where it seems to run stable but doesn’t take off on me.

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