Puch Maxi Maintenance and Tools Guide

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This page provides an in-depth guide to the maintenance of a Puch Maxi or Newport. This is only a starting point, and can be used by new or experienced riders.

Cut to the Chase

You're likely dealing with a 35+ year old machine in bad shape. Use your brain here - it's time for a major overhaul, not simply a carb clean. Here's what anyone should do w/ an old moped that has not been properly maintained over the years:

TIP: use a flashlight to look at parts up close. Clean off grease with a rag to have a good look.

1. Drain all fluids. This means draining the transmission fluid (bolt is on the underside of the crankcase) and draining the gas/oil mixture. Hopefully if the moped has been in storage, it has no fluid in it.

2. Tear down tools. Make a detailed list of all tools needed to completely tear down the the top end, the bottom end (including clutch and flywheel), and the wheel hubs. This should include a clutch puller ($12.50), a screwdriver (free - I bet you have one), a flywheel puller ($13.50), an impact screwdriver ($9 at Harbor Freight), cone wrench ($5, get the cheap one), circlip pliers ($10-$20) (there are circlips on the front gear and clutch side of crank), a set of standard and deep sockets (price varies wildly, you may already own these, or if you're broke buy exactly what you need used or from Harbor Freight) (small deep socket to remove carb atomizer, an extension to remove the exhaust), and a rubber mallet ($10). If you owned absolutely 0 tools, you should be able to get all tools for under $100, assuming you're doing a lot of this used/Harbor Freight.

3. General tear down. Remove the carb. Then remove the exhaust. Then the clutch. Then the flywheel. Then the top end. Then the bottom end. Then the wheels. I put related parts into separate ziploc bags (e.g. all carb parts into one bag), and I label the bags with a marker, then put the bags into a box. Time = 15 min to 1 hour? (depending on your skill)

4. Detailed tear down. Completely tear down the carb. Now completely tear down the bottom end. Time = 30 minutes? (depending on skill)

5. Inspect your frame and crankcase. Look for any cracks, holes, or other damage. Determine if the damage is really an issue (sometimes what appears to be damage is only cosmetic). Sometimes there will appear to be cracks, but it's just manufacturing defects in the crackcase, or cracks in the paint.

6. Inspect everything else. You may need to clean off the gunk to have a good look. Make a very detailed list of all broken/missing parts. If you aren't sure about something (e.g. is my crank ok?) take it to someone who knows. Look at the service manual and ask around if you aren't sure about something. For example, here's a list for a moped in poor shape:

  • missing 1 engine support bolt (need new bolt and nut)
  • spark plug and wire worn (need new spark plug, boot, and wire)
  • fuel line and filter are old (need new fuel line, clamps, and filter)
  • bearings/seals (unknown age, replace seals definitely, bearings may be ok)
  • damaged piston/rings/cylinder. (either buy a kit, or cylinder hone+new piston)
  • all cables worn. (need new cable set)
  • tires are bad (need new tires, tubes, and rim strips)
  • brake pads worn (need new brake shoes)
  • drive and pedal chains heavily rusted and worn (need new chains)
  • cone nuts/cups/bearings bad in rear wheel (need new cups, cones, and bearings)
  • carb parts are missing (need a rebuild kit + missing parts)
  • finally, you will need all gaskets and the paper washers for the drain bolt and fill bolt for transmission fluid. Each time you replace the transmission fluid, you should change those two paper washers. It's also a good idea to replace your petcock as these often leak.
  • it's not absolutely necessary, but if you have the crankcase opened, and you're replacing the bearings and seals, it might make sense to upgrade to a performance crank. A new racing crank should cost around $100-$150. This way, you won't have to remove the bearings from the old crank, but can instead throw the whole thing away.
  • it's also a good idea to replace the clutch brass bushing. These wear out over time, and they cost about $7 for a new one

Don't just try to clean the carb and start it!! This would be the lazy/bad way to deal with a 35 year old machine. Don't you dare buy an aftermarket carb/exhaust/kit/intake yet!! Don't buy *any* parts until you've done a full assessment of what you're working with!! This assessment should only take an afternoon, and it will guide you through your build.

Now that you've done a full assessment of the moped, you can buy the parts you need, rebuild/clean everything, and put everything back together. If you tear it down and find that most parts are beyond repair, you may want to consider parting out the moped for the parts that remain, or buying a new engine that's in better condition if it's in very poor shape like the one listed above.

This is where you start shopping around, talking to people about options, and looking at different online sellers of moped things (lucky 2 strokes, moped junkyard, treatland, 1977 mopeds, myrons mopeds, etc.).

Welcome or Warning: Mopeds as a Hobby

In general in the US, since 1985 mopeds have not been bought and sold primarily as reliable transportation (tomos being the only exception). Availability of parts and repair shops today in the US is non-existent when compared with cars, motorcycles, and scooter shops. For reliable transportation only, you should think long and hard before buying a moped. This is really a subculture of enthusiasts, it's not a good idea to own one unless you're willing to put in the time to maintain it and do the research on your own (there are some shops that work on mopeds, but this is fairly rare). However, the enjoyment of a moped is in the tinkering, modifications, and aesthetics of a moped. Buying a moped is like buying a VW van, the people who love them pour money and time into modifications and they spend time doing research and doing at least some of the work themselves. Most people who want to just get around cheap buy a Honda Civic, not a classic car. The same idea goes for mopeds.

Bottom line: if you're wanting a moped for cheap transportation only and you have no interest beyond getting from point A to point B as cheap as possible, don't buy a moped. It may be a better idea to stick to scooters and motorcycles if you have no interest in the hobby aspect of mopeds, as mopeds take more attention and research than something like a Vespa scooter, Honda motorcycle, or a new cheap asian scooter. There are plenty of used scooters and motorcycles that can be had at relatively low prices, and even new asian scooters can be very cheap. Furthermore, Vespa and Honda for example are still both in business, have dealerships around the world, and have authentic stock parts available. Many shops know how to work on scooters and motorcycles. For a moped, you may be limited to one shop in your area (if you're lucky), and you'll be somewhat on your own to figure issues out.

Genuine OEM Parts vs Chinese Parts

Before you get too excited about those $4 bearings and $3 nuts you need for your moped, watch this video. It's highly recommended that to get your moped up to stock, you use a place that supplies OEM parts, and not go the route of filling your moped with Chinese garbage. Sure, you'll save money. But are the you really wanting these low quality parts on your moped?

One thing to note: just because you see a brand name that was great 40 years ago doesn't mean it's great today. For example, the new bing carbs aren't made to the same quality standard as the old bing carbs.

Here's a place that sells OEM parts.

http://www.myronsmopeds.com/

You know how with your car/motorcycle/scooter the manufacturer recommends that you buy genuine parts from the manufacturer? There's a good reason for that, and it's not so they can rip you off. The world today is FULL of cheap Chinese crap, made of low quality materials, and made to poor tolerances. This includes things from bearings to nuts and bolts to carbs to intakes and all the rest. You'll notice that things may not fit so well, or parts prematurely wear out.

The problem with mopeds is that they've stopped making parts, and now a lot of the parts are coming out of China. You can't just run down the street an get an OEM part anymore. Now you're having to find a few specialized dealers who still have some parts leftover from 30 years ago. As an example, you can buy new Chinese cone nuts from treatland, and they will cost you $3.50. If you want the Puch genuine cone nuts, you're looking at more like $25 per cone nut.

An OEM part with *always* be better than some cheap aftermarket part. Buyer beware when it comes to a deal that seems too good to be true.

Once your moped is running stock, feel free to add high quality aftermarket parts. These parts will always be branded, and they will be from higher quality companies like Polini, Malossi, Airsal, MLM. It is worth making your moped full of OEM parts + high quality aftermarket parts. Don't mix Chinese junk in with this.

Basics of the Puch Maxi E50 Operation

For additional information, see the E50 wiki page

It is good to understand how a 2 stroke moped works. This will help to guide you in the process. To understand the basics of a 2 stroke engine, read the wikipedia article.

1. Bottom end. This refers to the crankcase which contains the main gear and the crankshaft. The crankshaft is the heart of the moped, and it's connected to the piston, the flywheel, the clutch, and the main gear.

2. Top End. The top end includes the cylinder, the head, the piston, and the rings. The top end is held in place by cylinder studs that are attached to the crankcase. The piston is connected to the crankshaft by a wrist pin and a clip on each side of the wrist pin. There is a groove where a ring sits in the piston. This ring is compressed to push it into the cylinder, and there is a small gap ("ring gap") in the piston ring that should be measured prior to installation. When the piston moves through the cylinder, pressure is created between the piston and head. A spark plug is connected to the head. Air and fuel mixture move into the top of the cylinder and exhaust moves out of the bottom of the cylinder.

3. Clutch. The E50 engine uses a centrifugal clutch. This type of clutch is also used in other 2 stroke motorcycles. This clutch is automatic, and as the RPMs of the engine increase, the clutch arms move outward, and at some point by friction, engage to the clutch bell, and help to rotate the main gear. The clutch works in two ways:

  • starting. on the backside of the starter plate is a ring of cork adhered to the plate. When you pull the starter lever, you are forcing this starter plate against another plate to then rotate the main gear and start the engine. Once the engine starts, you release the starter lever, and the clutch stops spinning
  • engagement. at a certain RPM, the clutch arms will engage the clutch bell. The point at which the arms engage depends on the tension of the clutch springs, the weight of the clutch arms, and the amount that the screws for the clutch arms are turned. Tuning the clutch is beyond the scope of this page, and does not need to be part of first getting your moped to operate properly.

4. Electrical. When the crankshaft rotates, the flywheel also rotates. There is a stator behind the flywheel. When the flywheel rotates, current will flow through the coils of wire, and this provides the electricity for the moped (spark plug, lights, switches, etc.)

General Maintenance Up-Front Issues

1. Before you start anything, check your local laws on registration, licensing, insurance, and any other issues. You will want to take care of all of these issues before starting with maintenance. If for example your state requires registration, you may need to get license plates so that you can ride on the streets. It will be hard to maintain your moped if you can't legally ride!

2. You need both the owner and service manuals for your model. Many manuals are available as free pdfs online. You may want to print the manuals to have a hard copy, but this is up to you. If you can't find the exact manual for your moped, there may be differences. For example, the 1977 Puch Newport has wedge type handlebars and a different wiring diagram than the 1978 Puch Maxi.

3. There are no Puch moped dealerships, so some parts can be difficult to come by, though most needed parts can be easily obtained. Many of the parts you will need for the moped can be replaced with new parts available through places like treatland, Myrons Mopeds, or 1977 mopeds. However, many of these parts are no longer made and difficult to find. For example, if you strip the wedge nut on a 1977 Newport, you cannot simply buy a new wedge nut, so you'll have to find one of ebay, or fix the wedge nut you have. Triple tree tops are no longer sold, and are not as common as they once were. If the cups in your wheels are worn down, you cannot just order new cups from a dealership. To compare with scooters for example, I can go to a Vespa dealership any day of the week and buy parts in stock for a 40 year old scooter. They still have nearly every single Vespa part available. For mopeds, this is not the case, and sometimes you'll have to hunt for parts, even though the puch maxi is one of the most common mopeds.

4. The cost of maintenance is based on your available work space, tools, and experience. Someone with a well lit garage and work bench with a full set of tools and years of experience will have a far easier time than someone who is new to mopeds working in their living room

5. If you have just bought a used moped, the best option would be to do every single maintenance item listed in the service manual. The needs of your moped may vary considerably.

6. Do not buy a single performance part until your moped is running correctly as a stock moped. A correctly running stock moped means the following: it should start on the first kick, the moped should idle while the rear wheel remains stationary, and you should be able to reach 25mph. Until all of these can be achieved, you should never buy a performance part of any kind. Don't even think about buying a kit, performance pipe, or anything else until you're reaching 25mph. Otherwise, you're wasting money to try to make up for a problem you need to fix.

Recommended Tools

If you do not own any tools, the cost of tools can be significant. Additionally, there are many ways you can go about fixing things, so this is by no means the final answer. There are many ways to obtain tools, and the quality can vary significantly. Below are recommended steps, but nothing here is definitive, and many people will disagree or use other things, but this can be used as a starting point. If you find another way that works, by all means, go ahead, and please update this page! With experience, you can build up a tool set and buy higher quality tools.

1. Metric Socket set. There are endless options here, and any basic socket set will work. One issue, you will need a 30mm socket (this will use a 1/2" drive) to torque the steering head nut. A set of Tekton sockets is one options among many others. A 30mm socket will cost about $10. Keep in mind, you will need some deep sockets, like for your carb atomizer and exhaust. If you're starting out, you can probably get all sockets for less than $20.

2. Piston stop, $7.25

3. Flywheel puller, $13.50.

4. Clutch puller, $12.50

5. 1/4" and 3/8" torque wrenches from Harbor Freight, $11 each on sale. There are many sizes of torque wrenches for reaching different specifications. You will need a torque wrench where the torque specification you're trying to achieve falls within the middle range of the torque wrench. For example, a 3/8" torque wrench has a range of 5-80 ft-lbs. It is not recommended to use this torque wrench to achieve values that are right on the ends of the values, therefore for a 6 ft-lb bolt, you will want to use a torque wrench. Many people recommend Harbor Freight, as the 3/8" and 1/4" torque wrenches go on sale for $11 each. You need to follow all torque specifications listed in the manual.

6. 15mm Cone wrench, $8.54. This is needed to remove the cone nuts on your wheels to access the ball bearings.

7. Bearing pullers, free. These can be borrowed from any auto parts store with a refundable deposit. You will need these for doing a bottom end rebuild.

8. Impact screwdriver, $9 from Harbor Freight. You will need this to remove the screws on the clutch cover and engine case, a normal screwdriver will be very difficult.

9. Feeler gauges. These are necessary for setting your ring gap, setting the spark plug gap, and setting your timing on points.

10. Timing gun. Once you've set your timing, it's good to check your timing with a timing gun.

Recommended Fluids

1. Two stroke oil. There are many options here, so there's no hard and fast answer. One option is Amsoil SABER® Professional Synthetic 2-Stroke Oil, $12/quart.

2. Automatic transmission fluid. Again, no hard and fast answer on this one. One option is Cool 2 Cool CTF-R Clutch Fluid, $13.95

3. Loctite 242, $4. When you install any fastener, it is good practice to apply some threadlocker to obtain a better connection.

4. Compressed air can. You'll want this for cleaning out your carb.

5. Carb cleaner. When you clean your carb, there are several methods. You can buy a can of compressed carb cleaner, you can soak the carb in pinesol, or and you can use compressed air to blow out the jets. You will also want a very thing piece of wire to clean out the jets, a small guitar string or piece from a wire wheel can work. Thicker wire will not be able to get into the main jet hole.

6. Permatex® Copper Spray-A-Gasket® Hi-Temp Sealant, $10 (used on gaskets in contact with the cylinder)

7. Phil Wood Grease, $10. Used for greasing up ball bearings

Recommended Parts

This section really depends on the condition of your moped. You may not need to buy a single part, or you may need to buy a considerable number of things

1. Spark plugs ($4 each, buy several), new wire, and new cap ($3). I recommend purchasing new NGK spark plugs, and NGK boot, and a 1 ft section of wire. There's no need to buy a premade boot and wire, you can make this yourself with NGK parts.

2. Ball bearings and grease. You will want to replace the ball bearings in your front and rear wheel (some have caged bearings that do not need to be replaced. A set of ball bearings for a wheel is $2, so it's good to spend the $4 and replace all ball bearings in both wheels (if they both have them). You also need some grease, Phil Wood for $7 works.

3. New fuel line, 4 fuel line clamps, and in-line fuel filter.

4. Drive chain ($24.50) and chain breaker ($27). If your chain is old and damaged, replace it. If it's just dirty, you can clean and grease it. Instead of a chain breaker, some people have used a bunch and socket.

5. Pedal chain (about $10) and chain breaker (about $10). The pins are different than the drive chain, so either get two chain breakers, or use the center punch.

6. New tires, tubes, and rim strips. There are many tire options, one popular option is the Gazelle M62 tires. However, these are larger than stock, and there are issues with fit in the front fender and rear swingarm. Tires are about $60 for the pair, tubes are less than $10 each, and rim strips can be obtained from a bicycle shop (motorcycle shops may not have this small size on hand). Velox rim strip cloth is a popular brand. If you're replacing your tires, it's a good idea to replace the inner tubes and rim strips at the same time.

7. Bicycle pump. You'll want this to pump up your tires. It is good to check your tire pressure regularly, while the moped is cold.

8. Carb rebuild set. If your moped has been sitting for decades, you will likely want to rebuild your carb to replace every single piece in the carb that isn't metal. There are carb kits that include the float, gaskets, etc.

9. New bearings and seals. A seal set is $10, and you need 4 bearings. The bearings can range from $4-$10. A new set of bearings and seals should not cost over $50.

10. Gasket set. You have two options. Either buy a complete gasket set for $10 or make gaskets yourself. There's also the option of buying single gaskets, and this can be done if you want a higher quality gasket (like a $5 crush exhaust gasket) or you want to replace a single gasket. Many people swear by cutting their own gaskets, so gaskets are basically free. Other people buy gaskets. It's all up to you.

Recommended Engine Maintenance

If you really want a properly running moped, you'll need to go through this carefully when you get it. Following these steps below, you can have a rock solid and reliable moped, and all of this can be done for cheap if you take your time and plan, and do not buy expensive and unnecessary tools and parts. Some people may argue that doing all of this up front is not necessary, but working on a moped is no different than anything else. All machines require maintenance, and if you're buying a used 35 year old moped, you have no idea how it's been maintained. These steps are relatively low cost, you'll be restoring your moped to excellent running condition, it will be more safe, and you can be fairly sure you won't have any problems.

Most of the removal of parts can be done with the moped on the kickstand, and I find it's easier that way. I believe all of this should be done before Fred's Guide, as this will likely eliminate the need to diagnose problems. Once you have completed this thorough process, you can then move on to verifying that you've done all of this correctly.

As a minimum, you will likely want to perform every single maintenance item in the service manual, plus follow Fred's guide. For something that's been sitting for decades, you must assume that many of the non-metal parts will need to be replaced. It's all up to you though, if you feel comfortable running around on a moped that's been sitting for 20 years without checking things in detail, it's completely up to you. If the previous owner has regularly been maintaining the moped, these items may not be necessary. However, more likely than not, many of these items have not been done in decades, and it's time to go through everything.

Removal of parts

Before removing anything, you should drain all fluids. Drain the gas/oil mix by removing the fuel line from the petcock. Remove the automatic transmission fluid by first warming up the moped, then removing the drain bolt on the underside of the crankcase. Take used fluids to your local auto parts store for disposal.

1. Remove carb for rebuilding and cleaning. To do this, turn your petcock to the off position, and pull the fuel line from the carb. Then loosen the bolt where the carb connects to the intake. Now turn the carb to the left so the top of the carb is facing away from the moped. Now jiggle the carb till it comes off. Now unscrew the top two screws and remove the carb top from the body. Now put the carb body in a ziploc bag and set aside. Now remove the carb top from the throttle cable and put the carb top in the baggie as well. Removal of the carb should take less than 5 minutes.

2. Remove the exhaust. This is done by removing the two 10mm screws at the underside of the top end. You will deep a deep 10mm socket for this one. Removal of the exhaust should take less than 5 minutes.

2. Remove the clutch. Follow the steps for removing the clutch. Once you remove the clutch, put all parts in a plastic bag and set aside. Removing the clutch should take less than 5 minutes.

3. Remove the flywheel. Put all parts in a plastic bag. Removal of the flywheel should take less than 5 minutes.

4. Remove the top end. There are four 10mm screws holding the head onto the cylinder. Remove these 4 nuts. Now you can slide the head and cylinder from the top end. Removal of the top end should take less than 5 minutes.

5. Remove the bottom end. There are 3 bolts on the carb side of the moped. Remove these bolts. This should take less than 5 minutes.

Cleaning of Parts

Now that you've removed everything from the moped, there's an order of operations here:

  • Step 1: replace the bearings and seals in your crankcase
  • Step 2: Inspect your piston, piston rings, and cylinder, then reinstall the top end
  • Step 3: Rebuild your carb, then reinstall it
  • Step 4: clean the points on your flywheel and reinstall
  • Step 5: Inspect the condition of your clutch, and reinstall

1. Opening the crankcase, and replacing the bearings and seals. This is something that has likely not been done in decades (if ever), so it's a very good idea to do this when you get an old and poorly running moped. Follow the bottom end rebuild guide on how to install new bearings and seals. This process should take anywhere from 2-3 hours.

2. Once your engine case is sealed, let it sit for 24 hours to cure, then reinstall on the moped. Run the wires and grommet back through the case. You should now inspect the condition of the cylinder, piston, and piston ring. The piston and cylinder should be smooth, with no scoring. Look inside the cylinder. You can remove the piston ring from the piston, and place it inside the cylinder to check the ring gap against specifications. If the piston ring gap is way too large, you can buy new piston rings. If you cylinder is scored or piston damaged, you should have the cylinder bored and honed, and you will need to buy a larger piston and piston rings to match. You can bore and hone a cylinder yourself, or pay a shop like $50 to do it for you. A new piston and rings is about $25. Do not buy a kit to fix a damaged cylinder, simply fix what you have.

3. Clean up your cylinder. You should remove all remnants of the old gaskets from the exhaust and intake ports. Before you put the cylinder back on, install the intake back on the cylinder, and install a new gasket. You will need to install a new base gasket before installing the cylinder back on the bottom end. Use copper spray a gasket for these three gaskets: your intake gasket, the base gasket, and your exhaust gasket. Once your cylinder in installed, put the head back on, and torque down the nuts. If your nuts are rusted, you may want to buy M6 coupler nuts from the hardware store, and apply some loctite prior to putting the coupler nuts back on the existing studs.

4. clean and rebuild your carb. Clean out all metal parts, using the wire bit to clean all tiny holes. Replace every single part that isn't metal. Even if it looks good, it's likely not performing as it should. Check the carb diagram to be sure you have every single part on the carb. A simple cleaning is good on a well maintained carb, but if your carb has been sitting for 30 years, it's time for a rebuild. A rebuild kit shouldn't be more than $20 or so.

5. Before you put the flywheel back on, clean the points per the manufacturer recommendations.

6. You should put in a new clutch gasket before reinstalling the clutch. You have now installed all but one of the gaskets (there is another gaskets in the exhaust pipe you removed earlier. Before installing the clutch, inspect the clutch for wear. Clutch tuning can be done later, but for now install the clutch back as is. If you want to do some clutch tuning now, you will need some stiffer springs. These can be purchased for $3.50 per spring. Read more about this in the clutch tuning section. Again for stock, this isn't something you need to do.

7. Replace the spark plug, wire, and boot. Total cost should be about $10

8. Replace the fuel line and filter. Total cost should be less than $10

9. Reinstall your carb.

10. Replace the gasket in your exhaust. Now put a new exhaust gasket on the exhaust, and fit the exhaust to the underside of the cylinder. Torque down the cylinder nuts to spec. Be sure to apply loctite.

Additional Recommended Maintenance

These things should be checked:

1. Cables, $31.50. Likely your cables are old and worn out. It's good to replace all old cables on any 2 wheeler, whether it's a bicycle or motorcycle. This is a safety issue, as a snapped brake cable could be fatal.

2. Wheels and tires. First, check your tires. Are there any cracks? Is there any tread left? Don't risk it, you likely need new tires if this has been sitting for decades. Once your tires are replaced, now it's time to check the hubs. You should replace the ball bearings and replace the grease. A set of ball bearings is $2 per wheel, so why not replace them? If you open up your wheel and you find that the ball bearings, cups, and cones are damaged, you will need to replace the cups and cones in addition to the bearings. The cones are widely available, but the cups are difficult to find. If you are unable to find cups, you can convert the wheel to a sealed bearing setup. Some of the puch models had the rear wheel as a fixed bearing as the stock condition.

3. Brake pads, $15 per wheel. When you pulled your bearings apart, you should inspect the condition of the brake pads. Are they worn down and glassy? If so, you should replace the brake pads. If however you get decent braking power, just keep what you have. I personally don't like to skimp on anything related to braking power.

3. Chains. Look at your drive and pedal chains. A good chain should be free of gunk and well greased. The drive chain should have about 3/4" of play in it. Is yours rusted and full of gunk? It's probably best to chuck it and get a new chain. If however the chain is in good condition, you should clean the chain and apply fresh grease. A new pedal chain can be purchased from a bicycle shop for about $10. The drive chain will be around $25.

4. Throttle cable. With the moped off, open the throttle up fully and release. Does it immediately snap back? If so, good! If not, you need to figure out why it's not snapping back, as this is a dangerous condition if it sticks while you're riding.