If you insist on building one yourself, this guide will help you do so.
These are just basic 49cc, 68cc, or 80cc assembly instructions. This is a how-to guide on building a running bike with just what is in the kit. These will not last nearly as long as ours or run as safely because there is no preventative maintenance or extra features included. We build ours with many extra parts to ensure safety and reliability.
Things you will need to build your motorbike:
The right style of bike=======Obviously necessary
An Engine Kit============Obviously necessary
Flathead Screwdriver=======Necessary but not used often
Phillips Screwdriver========Necessary but not used often
10mm Wrench===========Used a lot
Adjustable Wrench========Used a lot
Tin Snips===============Helpful but optional
Vice Grips==============Helpful but optional
Allen Wrench Set========= Necessary but not used often
Hammer===============Helpful but optional
Zip-ties================Helpful but optional
About 10 hours on average for a first time builder
You will need about a 10'x10' area. Please choose an area you do not mind getting greasy, oily, spilling gas on, etc. Preferably in the driveway or the garage.
I have enough experience that I can build these on my own but some parts may require an extra set of eyes or hands. It is recommended that you have someone hold either the bike, tires, engine, fuel tank, etc in place as you work on them. You will also need to have a moderate amount of strength the to get the bolts tight enough.
**Please remember that you do not need to over tighten anything. Stripped bolts should be replaced immediately.
This specific bolt came off a chain tensioner. Stripped bolts do not grip as tight and having loose bolts can cause something to shift or slip. If it does, you could break your chain or run into other complications. A few minutes to switch out a stripped bolt can save you hours of frustration later.
INSTALLING REAR SPROCKET:
There are two rear sprocket rubber pads. Cut one of them between the drilled holes.
Place the cut one inside of the spokes.
Place the other packer on the outside of the spokes.
Thread the nine bolts through the sprocket and use the 1/3 or 1/5 moon backing plates on the inside. Tighten all nine bolts moving across in a star fashion and a little at a time to allow for an even pull down. Once the
sprocket is tight spin the wheel and check that the sprocket runs true. Deviation can be no more than 1.5mm either way. Any side-to-side excess deviation can be corrected by spinning the wheel and then tightening the sprocket where needed in order to get correct alignment. Make sure bolts are tight.
If your rear sprocket is not flat at the teeth:
Notice that concavity or indentation of teeth of the rear sprocket is outward on mountain bikes. This helps on mountain style tires to keep the chain away from the rubber nubs on the sides of the tires. On cruiser styles or road bikes, it is recommended that the indentation of the rear sprocket face inwards. This helps keep the chain closer to the inside of the wheel and spokes and allows for better clearance of the rear stays of the bicycle frame.
STEP 4 COMPLETED
Here is how it looks when completed.
MOUNTING ENGINE TO FRAME:
Mount the engine into the frame. This is pretty self explanatory. Some bikes have a large diameter lower bar and some need clearance for the air intake so you may need to use the adapter plates and bolts(that may or may not be) provided in the kit. For this, get creative. There are many ways to make your own mount. Below is one way that works very well, so well that I trust is on my personal motorbike! This method shown below only requires a strip of the steel and a few nuts and bolts. This method also works on any size frame of done correctly. To prevent from scratching your paint, and reduce vibration and noise, it may help to put some padding under the mount.
As long as the bolts are strong enough to hold it securely, it should work. Also make sure your mounting system does not prevent the engine from staying in line. Notice just above the mount, there is a hose clamp around the muffler and the frame. This also helps hold the engine in place and this clamp can be adjusted to align the engine in either direction.
The new style throttle is fitted to the r/h side of the handle bars - before you slip the throttle onto bars you can drill a 5mm hole in the handle bar 125mm from the end-OPTIONAL. Put a drop of machine oil into the cable sheath when you have it apart. Care should be taken with the cable location grove - if you are too rough with it, you will break it. Be gentle when installing the throttle. The new
style throttle has a kill switch incorporated into it. Wire one kill switch wire to the black wire from engine and the other kill switch wire to the blue wire from the engine. Pressing kill switch will cut power to the spark plug and stop engine running. The kill switch can also be wired as follows: 1 wire to earth (anywhere
on bike frame) and the 2nd wire to the white wire (from engine). It is not important which method you choose - both wiring methods are equally effective.
Mount the clutch lever. This should be done before you put the left handle on. It should be mounted as shown. The clutch lever cable can be slipped into the groove in front and hooks into the swinging piece between the lever and handle body. Pull the lever to reveal the slot where the cable clips in.
STEP 7 COMPLETE
There are a few different ways to effectively install the clutch cable.
Here is what the clutch cable connection might look like at the motor, this is incorrect. Normally, the smaller longer spring would be placed between the inner cable guide and the clutch arm. In this set up, there is a carburetor spring on the outside of the clutch arm held in by a cable keeper. It is normal for your wires to fray over time. A piece if heat shrink tubing around them will prevent them from fraying but is not necessary. The excess wiring can either be trimmed off or zip-tied to the clutch arm for adjustments if necessary.
The black wiring on the left is where the larger spring should go. It simply slips around the cable and acts as a heat shield between the clutch cable sleeve and the heat of the engine. It is not shown here.
Screw in the fuel valve filter combo into the tank and then mount the tank. Tip... Wrap top frame tube with a tube from a tire. This reduces vibration/noise and protects your paint from getting scratched. If you have cables that run on the top bar, make sure you dont pinch them down when you apply the tank. Apply Teflon tape to thread if your fuel valve is leaking.
Mount your CDI box.
Tip...Use 2 high quality cable zip ties. It is extremely important that you do not get cheap ones as these strip and break quite easily. Go up and over and around the coil and zip tie it to the frame. Loop one zip tie up and over and also through the holes that would normally have the screws
going through them. This is a different method than using the screws that come with the kit. We prefer to use the hardware to mount ours and reinforce it with zip-ties. You will have a more solid mount and not break the coil. It is not hard the break the coil ears off using the screws. Wire
Connections: Blue to Blue and Black To Black. Also wire in kill switch to black and blue wires as previously explained. The white wire is generator and has a max output of .5A 7.5V. Anything that draws more current connected to the white wire will kill the motor. For example, you can use the white wire to run a 6 volt headlight. The negative lead of the headlight could either run to the black wire or be grounded on the frame. The kill switch can also be wired as follows: 1 wire to earth (anywhere on bike frame) and the 2nd wire to
the white wire (from engine). It is not important which method you choose - both wiring methods are equally effective. It is very important to ensure the cover plate on the magneto remains tightly sealed. You can use a good brand of thread sealer on them to help hold them in place. If water is allowed to get into the magneto chamber, it could cause the magneto to burn out.
Testing resistance on Magneto coil should read:
blue to black = 323ohms; black to white = 2.3ohms
Special Note: If your spark plug has its crown screwed on. Unscrew it and remove it so that you can put your spark plug cap on. Failure to remove this Crown can damage or ruin the Spark Plug Cap.
This next step is recommended but not always necessary.
Lets mount the chain tensioner.
Here is what the tensioner looks like installed. Notice that we put band steel over it to hold the wheel in the most upright position. This helps you get the most tension out of it for that extra slack you need to get rid of. It may be necessary to take out some links if your chain is to long.
Put the chain on.
There are multiple ways of doing this.
Remove the 3 screws from Counter shaft side cover and also remove spark plug. Remove clip from master link of chain and then thread chain up and over counter shaft sprocket by rotating the sprocket using tool.
Having the spark plug removed allows engine to be turned easily to thread chain. Tip... Since you have this cover off, hold clutch arm and rotate cover and pull clutch arm out of cover and then grease it and rotate it
back in. Option 2: You do not need to remove the cover if you lock the clutch lever, thread the chain in, and use a flat head screwdriver to rotate the clutch sprocket around until the chain comes back out.
Put some grease on the shaft and in the hole of the clutch arm. Do not be afraid to over-do it.
Optional: Install chain guard.
You can paint your chain guard or pretty much do any modifications you can think of to it. On this one we had to cut out sections for the brakes to fit in.
We always add a chain guard for your protection but you always have the option to do it on your own or not. We recommend it.
Use some tin snips to cut cover at the rear if needed. Use a good zip tie, metal stripping, or a rivet if you drilled the frame. The chain guard is secured in front by a nut that threads on the extra long bolt on the clutch panel. Its hard to miss. A 10mm wrench will tighten this down. Please remember to either use a locking nut or a lock washer.
Install exhaust pipe.
If you need to bend the pipe so it will not hit the pedals, it is recommended to clamp the pipe into wood blocks and bend. Do not bend exhaust mounted to engine. If you could break the motor itself. The exhaust pipe is very strong - much stronger than the 2 mounting studs on the motor.
Mount the carburetor.
Check the other screws including the brass fuel inlet screw for tightness. Typically they need some slight turning. Once the carburetor is on and tight, you are ready to connect the tank line to the carburetor. Tip ...Get and inline fuel filter. Even though the fuel petcock has a screen filter, it is porous
and allows sediment through. A high quality inline fuel filter with paper element is a better way to go and to keep fine particulate out of the carburetor and the engine running like new. Well the install is done. Mix your oil with the gas before adding to tank. Fuel up the bike and your ready to ride!
**Do not be discouraged if the bike doesn't start right away. Remember, this is a brand new engine and there has to be a little gas running through it first. It should start within a block of pedaling in gear. If it does not start, please check over your wiring, make sure your fuel valve is on, and make sure you have the everything else visibly correct. Is your spark plugged hooked up? Is your clutch at the right tension? There are troubleshooting guides online that you can look through. It is extremely rare that a brand new engine will not start. You are always welcome to bring yours in and let us take a look. It is so rare that in all the years we have been building bikes, we have never came across that issue. Maybe we are just that good at building bikes.... :)
**Please note that the reliability and safety of the motorbike is based greatly on the way it is built. We can not assure safety or quality of anything we did not build. Not all motorbikes are the same. These are only rough guidelines to putting together your engine kit.
Racks, lights, and other features and accessories should be put on only after you have your bike up and running as they can get in the way of building it.
For questions, comments, or more information, feel free to email us at email@example.com
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