How to Chamber Muffler,

easy , no need anything special.

How to fix motorized bike cylinder bolt stripped, EASY WAY!


A little demonstration on How to adjust/fix your chain tensioner, without going into your spokes.





How to fix motorized bike Broken chain , no special tools needed!


How to fix motorized bike chain falling off, EASY WAY!

Always carry an Extra OEM spark plugs or J8C spark plug, few tools, spare tube & fix flat kits or tools with you when riding.
Motorized Bikes:
For Sale Bikes: Up For Grabs!!
Great for any tasks. Easy, cheap maintenance. $250 and up

Installed, all brand new engine and bikes. Great for cruising & getting around town.
Great MPG: up to 150MPG
Speed: 30 MPH up to 45 MPH “depending on weight and order”
For more information please contact me.

Congratulations and thank you for choosing Yoopti Bikes!
I am committed to helping the novice hobbyist, seasoned old-timers, and professional outfits enjoy the best possible bicycle motorizing experience.
If this is your first bicycle motorizing project, I am excited to help answer your questions and provide you with tips, so you can have a fun ride and enjoy your new, motorized bike. If you’re an old hat at this, I’ve got tips, tricks, and suggestions that can help you create another motorized masterpiece.
Please contact me if you have any questions or comments!


BEST DEAL LINK 1 :::: Link 2 :::: Link 3 ::::
Add 5 to 6 ounces of 2 STROKE OIL to every gallon of Gas, or 2.5 to 3 ounces of 2 STROKE OIL to every gas fill up.

( remember your gas tank is only 1/2 gallon so if you refilling or adding to your gas & already have some gas left in your

gas tank then just add 2oz of oil )


Using a 50cc engine is the safest motor engine for bikes.

Using a 66cc~80cc motor 'aka 80cc' engine is little risky unless you know how to work on motorbikes.

Using a 100cc motor engine is not recommended at all.

__ 50cc motor is like Toyota , they will run & last for a very long time as long as you add oil to gas & do simple maintenance, its a little slow at take off but it is a long lasting motor.

__ 80cc motor has lots of torque at take off but its almost as fast as 50cc except you have to remember your bottom part is the same as 50cc motor, the only thing has changed is your upper part that has increased from 50cc to higher size cylinder '66cc ~ 80 cc' , another word you are putting more stress on piston rod & crankshaft, so pretty soon your engine will stop running simply because the bottom part is made for 50cc, Plus.. your spokes will break fast because you have more torque than 50cc.

__ 100cc? really? that is stupid! You will break spokes or hub & crankshaft piston rod & etc... as fast as your bike goes ... so it is NOT Recommended at all. The bottom is still the same that was designed for 50cc, now you want to put twice the power on it? Really? think about it. So NO to 100cc , do not waste your money period .

Picking sprocket size:
Higher tooth sprockets give you higher torque and lower top speeds, while fewer teeth will give you less torque and higher top speeds.
48-tooth sprocket – Highest torque, lowest top speed “breaks spokes”
44-tooth sprocket – Great balance between torque and speed “Recommended but breaks spokes”
40-tooth sprocket – Higher speeds, lower torque, safe ride “its okay but still sometimes it breaks spokes”
36-tooth sprocket – Reaches ultra-high top speeds and a faster finish, least torque and slower starts
Lower than 36 is the best performance, gas saving, and yeah no more breaking spokes.

2-Stroke engines offer more torque. They use a Gas/Oil Mixture. You don’t have to check the oil separately.
4-Stroke engines offer a quieter, less torque smoother ride. They emit less exhaust and only gas in the gas tank.

Ride Safe!
Be careful! always think like we have no right away, let the car go even if you have to but never cross their road, it is not worth the accident.
Also prevent getting flat tire by checking your tires at every stop. Thorns dont have a chance to go in tire all the way at once, but after a while, sitting on your tire, it punctures its way into your tire until it flattens your tire, so always check your tire before you get a flat tire.

invest on some tools, screwdrivers, a few pliers, non digital multi-tester, a few parts, like CDI, Magneto, Throttle handle in advance, trust me they are cheap on ebay, but it is worth your time and money, EBAY has bunch of cheap parts…

Flat Tires:
I don’t think anyone likes to get a flat tire, but it happens, but wouldn’t be nice to prevent it? yes & no… In most cases little thorn gets into tire first, and it takes a while to puncture its way into tire to flat the tube, so on every stop light check your both tires, if you see any foreign object trying to get into your tire remove it before its too late. Also it helps to keep your tires always in good shape and new, it is much easier to replace the old tire with a new one at home than fixing a flat tire on the road. There are times that it is unpredictable, for example a nail comes out of nowhere just to puncture your tire… yes my friend sometimes it just happens…
Read More…

If you need Spark Plug ASAP, buy J8C From Oreilly or any other auto parts store, but the wrench size is bigger:
Oreilly store have them.

1. Use sandpaper on glass to plane the head surface flat and increase its compression a little bit for more power. Also make your own head gasket out of high temp gasket material for it to seal properly.
2. Drill a bigger hole in the wrist pin for less vibration. Without this the engine will always be unreliable as it will shake loose nuts and bolts. Also a vibrating engine makes it uncomfortable to ride. If it still vibrates too much then you need to drill holes into the crank wheels with a 3/8″ carbide bit.
3. Take the screws off of the stator coil and clean off the shellac on those screw head contact areas. That is important because that screw to metal contact is the ground path for the high voltage coil and spark plug. The worse the contact is the weaker the spark will be which reduces engine power.
4. Replace the stock nuts/bolts/studs with a replacement kit from Sick Bike Parts. The stock ones are too buttery and will strip threads and break off. Also apply medium strength thread lock to all threads.
5. Lower the needle in the carburetor to the limit because the stock fuel to air ratio is too rich and will make the engine run rough and with less power. It will also cause plugs to foul and stop sparking. You will also need to buy a micro drill bit set and melt solder into the main jet and then drill it out to a smaller size. The stock main jet hole is too big and makes the engine run rich at full throttle. Also make sure the float stops fuel flow at the correct level which affects the fuel/air ratio.
6. Replace the restrictive stock air filter with a bigger foam one that needs to be oiled with engine oil before installing. This will let the engine breath better for more power. The stock one is too restrictive and causes the fuel/air mixture to be too rich.
7. Replace the stock spark plug with an Iridium one (#7 for moderate climates or #8 for hot climates). This gives a more consistent spark at a lower voltage for smoother more powerful running.
8. Put a fuel filter on the fuel line because the filter inside the gas tank won’t filter out the finer particles. Also there’s usually trash inside the fuel tank that should be cleaned out before use. If not then that will partially block the filter and limit fuel flow.
9. Once you get these mods done and want the engine to start easier, run smoother, and have better top speed then think about putting a good carburetor on that is fully adjustable with an idle jet as well as a main jet. Also a good aftermarket CDI will help in the same way.
10. Consider removing some of the baffles in the stock muffler for better top speed.
11. The most technical mod you can do is buy a rotary tool with cutting discs and mod the cylinder ports for more power. You can widen the intake and exhaust ports and lower the intake port (or take some off the bottom of the pistons intake skirt) so that it has a bit longer open port duration (120 degrees) which gives it more power all around.


Follow the link with lots of information.


Great Information you can find DIY & etc.. on this site:


Great Website for vintage Motorized bike geeks