moped points replacement draft Linda

Leon Swarmer /

Linda asked someone to write up a wiki page for points.

I have this started.

haven't touched cleaning and adjusting on the peds yet or four strokers and the pics aren't added yet, but I'd like to hear input.

yes, it is a draft and i'm plenty willing to change it.



For the purpose of this audience this will be written for two stroke, single cylinder engines unless I note differently. I'll add four stroke and multi cylinder engines at the bottom.

Contact points, ignition points are the same name for an essential piece of the ignition system.

What is a set of points? or What are points? Simply put a set of points is an on/off switch. ( pic 1) But it is a very special on on/off switch. It is spring loaded and usually closed. It is opened by a lobe or bulge (cam) that spins around and rubs a block. That opens the contacts about .015 inch (check your manual for exact measurements) and then the spring closes them soon after. Electricity from your coils under the flywheel goes through the points and then to your coil. The coil converts the 6 or 12 volts into high voltage stuff and sends it to your spark plug. Each time the crankshaft revolves the points open and close and send that voltage on. Sounds simple enough, right? The engine may be spinning at 4,000 rpm or more. That's a lot of opening and closing. In a one hour ride, we expect these to operate 240,000 times. They also have to open and close at the right time. The spark must hit shortly before the piston reaches top dead center. That give the fuel/air mix a bit of time to start ignition and to produce it's power on the way down. This is called timing. If the timing is off, the plug can fire while the intake port is still open and blow smoke through the air filter. .You won't be likely to start it. If the timing is way off the engine may start, but actually be running in reverse.

Because of the many ways of setting timing on different peds, that will not be addressed here.

Points give us trouble in many ways. They get old and worn. They can get oily or wet. Oil and water can conduct electricity way from where we want it. and lose all power. The wires going to them shake and break. The wires may rub against the inside of the flywheel and ground out. Mounting screws can vibrate loose (rarely) and the block no longer rubs against the cam. The spring can break and the points won't close. Screws or clips holding the wire to the points can disconnect. When I see peds running without a cover over their flywheels I can't help but think. "One splash of water can stop that bike."

To make our trouble worse, they hide under the flywheel. To clean or adjust points you need to be peering in a tiny space with a flashlight, a feeler gauge, maybe two screwdrivers in a place lower than your knees.

It is never fun. A lift or a table can hold a ped high enough to make the height better, but most of us don't have those.

So how do you replace points? Sorry, you gotta take off the flywheel. Many kinds of pullers are available and there is also the dreaded rubber mallet method. Here is where Honda owners are happy folk. The flywheel is bolted to crankshaft. With simple tools it can be taken off to easily expose the points.

(pic 2) . On this NC50 you can see where the gap should be measured, how the wires connect and a place for adjusting them. Take the sparkplug out of the engine. Disconnect the wires (keeping track of which ones go where) Unscrew the screw(s) holding the base of the points in place. Install the new points, but don't tighten up the mounting screws. Add the wires to it and nudge the points over to the crankshaft.

Hope you don't own a Garelli. Garellis have the cam for the points inside the flywheel (pic3)so they can't be set until the flywheel is in place. Motobecanes have a cam that is a separate piece (pic 4) that is mounted on the crankshaft. It must be in the right place or you will be in serious trouble. Ok, you can now turn the engine by hand (aren't you glad you pulled out the spark plug) Make sure you are turning it the same direction it runs. On the Honda Expresses with the tap starters you can have serious trouble if you turn them the wrong way. As you are slowly turning that engine you can see the cam on the crankshaft start to push the points away. You want the farthest place that the cam will push to be resting against the rubbing block. Gently push the assembly into the cam until the points open. Now grab your feeler gauge (pic 5), and get ready to put it in the gap. Slightly tighten the assembly mount. Open the points by hand and rest the feeler gauge between the round contacts (pic 6). With one hand you can use a screwdriver in the notch in the points to move the mounting plate to exactly where you want it. With your other hand drag the .015 (or your spec.) blade through the contacts, moving the first hand until there is barely a drag on the feeler gauge. With your third hand, tighten down the mounting plate. Again on the Garelli, the adjustment must be done with the flywheel in place working through the grooves. Check your timing. Cover everything up.

Put your spark plug back in, put away your tools and ride.

Re: moped points replacement draft Linda

Okay, I added a little formatting and copied it over to the wiki. Now, since this is the general forum, I'm sure SOMEONE will disagree with what you've written. Here's the cool thing, guys. It's in the WIKI. That means YOU CAN CHANGE IT if you don't like it. Sweet, huh?

Obviously it still needs the pictures, and I probably screwed up something by formatting it, or perhaps there's something else you people who understand points think should be added. All of that can be fixed/changed very easily, though. Leon got it off to a great start, but it's collaboration of many minds that makes the wiki truly great. So, let's collaborate, okay?

If any of you have problems with this or ideas for things to add but you don't want to mess with the wiki, post your collaborative ideas here and I'll fix/change/add/etc. for you.

Leon, on the pictures, you can upload them (just click on "upload file" in the wiki toolbox), or you can attach them here/give me a link to where they are, and I can upload and link them for you.

My comments:

1) THANK GOODNESS someone wrote this article! It was number one on the wanted pages list by a fair margin. Thank you!

2) The only thing I can think of that I'd really like to see added to it is a "dictionary" definition. Personally, I like the layman's definition much more useful, but for the sake of continuity, it would be nice to start it off with a short but technical definition.

3) I'm a little confused on some of the directions because I'm not sure how the Honda-specific directions mesh in with the general directions. I understand that the Honda flywheel comes off differently, but I'm not sure where/how/if the rest of the directions are different for mopeds other than Hondas. Maybe we could do like a general run-down, and then separate out the Honda stuff into another heading (and perhaps other brand-specific info)?

4) Unless you really want to, I don't think you need to go into cleaning the points because that's covered pretty well in Fred's Guide. Also, general flywheel removal is covered pretty well in the flywheel article, so that doesn't need much elaboration. Finally, on the 4-strokes, I guess I'll make this a question to everyone -- are many people going to use that info? We don't even have an article yet explaining a four-stroke motor, so explaining the points on them might be jumping the gun a bit. Leon, if you want to write it up and add it, that's fine, but I don't want you going to a bunch of extra work for nothing (unless you want to, of course).

Re: moped points replacement draft Linda

there is a really good description of the ignition system on the whole in A. Bells 2 stroke performance tuning book,

what eles is on ur list linda

other articles that need to be written

Just in case anyone else sees this and is inspired to contribute, here are the places to look for what else needs to be added:

1) The wanted pages. These are articles that people have linked to but do not exist yet.

2) My list of articles. I stole most of these from the wanted pages, but I organized them a bit and pulled out the ones I thought were most important/useful. A lot of it is pretty elementary, but it's all stuff that either I didn't know or don't know, so it IS possible for people to not know that information. You can see how much progress has been made since that list was started by how many of the links are now green instead of red.

3) The stubs. These are articles that people have stared but need more info. Some of these are in DESPERATE need of fleshing-out, so check out the articles and add where you can!

Also, Elliot, do you have a link for that book? It's mentioned in the Performance Tuning category, and I wanted to put in a link to it. I searched and I couldn't find it online... so if it's out there somewhere, I wanna know where!

Re: other articles that need to be written

Leon Swarmer /

From Wikipedaia

A contact breaker (or "points") is a type of electrical switch, and the term typically refers to the switching device found in the distributor of the ignition systems of spark-ignition internal combustion engines. (ok for peds, we dont have distributors,

modifies to this, l.f.)

A contact breaker (or "points") is a type of electrical switch, and the term typically refers to the switching device found under the flywheel of the ignition systems of spark-ignition internal combustion engines.

[edit] Purpose

The purpose of the contact breaker is to interrupt the current flowing in the primary circuit of the ignition coil. When this occurs, the collapsing current induces a high voltage in the secondary winding of the coil, which has very many more turns. This causes a very large voltage to appear at the coil output for a short period - enough to arc across the electrodes of a spark plug.

Leon again

mods for four stroke are pretty simple: They operate once every two revoltions of the engine and there are controlled by a lobe on the camshaft, not the crankshaft. They are not under the flywheel.

if someone is good on condensors, they can add here since it's a good idea to change the capacitor/condensor at the same time, and most are hidden there under the flywheel, too.

I'll consider the issues for other peds, too.

Thaks for putting it in place , Linda


Re: other articles that need to be written

Leon Swarmer /

pic 3


Re: moped points replacement draft Linda

Okay, I think I got all of that...

I wasn't sure where you wanted both of those pictures, so I just kind of picked somewhere. If you want them somewhere different or with other captions, let me know and I'll fix it. Also, on the NC50 points labeled picture, can you specify which shape corresponds to which part/function? It'd be great to have a labeled picture to go along with the first part about how they work.

I tried to move most of the brand-specific stuff to the end, but if I've missed something or messed something up, just say so and I can change it.

Re: moped points replacement draft Linda

Leon Swarmer /

how about?:

(pic 2) . On this NC50 you can see where the gap should be measured, (the lightning bolt) how the wires connect and a place for adjusting them (star) where the rubbing block touches the crankshaft (right arrow) and the top mounting screw (at the top of the triangle).

Gee Linda I bet it's killing you to look at such a dirty ped.

When I click on the enlarge, it didn't... maybe just my connection.

Re: moped points replacement draft Linda

Yay! That's exactly the explanation I was hoping for.

As for the dirtyness, well, the important parts are clean, right? That's what matters most. :)

Re: moped points replacement draft Linda

Leon Swarmer /

Anythign to make you happy. More pics later.

yep, it really needs to be clean around those points.

Re: moped points replacement draft Linda

Leon Swarmer /


On the Honda Expresses with the tap starters you can have serious trouble if you turn them the wrong way. could be moved down to Honda specific

pic of feeler gauge attached


Re: moped points replacement draft Linda

Leon Swarmer /

I obviously haven't figured out how to put them on the wiki

and yea, dirty points, too


Re: moped points replacement draft Linda

Leon Swarmer /

pic 6


Re: moped points replacement draft Linda

Leon Swarmer /

pointer ( ok , soldering iron it was just close) at rubbing block..if you want it


Re: moped points replacement draft Linda

Okay, I added the measuring picture and the rusty points pictures to the article. I made them them thumbnails just to try to keep all the info more or less together, but if they don't work for you, I can see what I can do to change it. I think there are at least a few people who have problems with the wiki doing strange things on them. I tried to put the picture with the soldering-iron pointer in, but the spacing refused to cooperate with me. I put the feeler gauge picture in the feeler gauge article and then linked that article to this article.

Just in case you want to have a little wiki fun too, here's how you add images:

1) Upload the image. break>

2) Go to the page you want the picture on. I usually open this in a new tab. Click on "Edit."

3) Re-type exactly (or copy/paste) the image name. It should be something like: Image:a really cool image.jpg. Then put [[ in front of it and ]] at the end. Now you'll have [[Image:a really cool image.jpg]] You can get more creative with it, but that's the basic idea.

Of course, if you don't want to mess with all that, you can always just send them to me and I'll be happy to do it. But now you (and whoever else might read this) know how to put images in should you so wish.

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