Bike Motor Kit

Shopping Cart:

0 / $0.00

Your shopping cart is empty!

Installation Guide & Help


Rev. March 2015

Note: Mechanical aptitude and ability is required to perform this installation. Many ”do it yourself“ backyard mechanics will find this project rewarding. A love of bicycles and small engines is the only required catalyst for this project. However, installation is sometimes best done by a professional auto or motorcycle mechanic. Older style bikes with 1 inch dia. to 30mm dia. steel 70 degree included angle frames require less modification to install the engine than do the later Taiwan bikes with large dia. downtube frames. We do not recommend what bike to use, but Cruiser type bikes work well. It is best to take your engine to the bike shop and compare fitting before buying a new bike. A rewarding joy and challenge is found in designing a custom installation of your own. Remember, a quality installation is paramount to safe usage and long term satisfaction. Have fun and good luck on your motorized bike project. Happy trails:


STEP 1 Mounting Engine to your Bicycle:

1. The engine mounts in the bike frame ”V“ above the peddle wheel sprocket. (see figure 1)

2. Consider using Masking or Duct Tape on the front down-tube & seat tube of your bicycle to protect the paint finish while test fitting the engine to your donor bike. If the distance between the two bars exceeds the engine mounting span then additional spacers or welded brackets are required. Mount the engine to the seat tube first and then fit to the front tube. 

Figure 1

Bikes with large front frame tube: Use ¼“ thick 1-1/8“ x 2-1/2“ steel plate with one hole in the center for a bolt to go through a drilled hole in tube frame and two holes for cap screws to go into engine block. Additional spacers maybe required depending on the donor bike. (see figure 2)

Figure 2. This alternate adapter plate is included in kit.

3. If the rear frame tube from the seat down to the pedal sprocket is too small to fit the rear engine mount, a rubber shim can be made from an old bicycle rubber inner tube. This also helps reduce engine vibration.

4. After the desired engine location is determined mount the engine to frame. Lock nuts and or use of Loctite is recommended to avoid loosening due to vibration. Note: All threads are metric.

STEP 2 Chain Wheel Sprocket Installation:

The Drive Chain Sprocket has a 36.9 mm dia. center hole and mounts on axel hub on the left side of the rear wheel against the spokes dish side in. The sprocket must fit over the hub in a perpendicular plane with the axle. This insures that your rear chain sprocket spins true with the rear bike wheel. *NOTE: On some older bike axle hubs like on coaster brake models it may be required to slightly enlarge the sprocket center hole to obtain a flush, and concentric fit next to the spokes. This is best done on a engine lathe by a professional machinist.

Apply thread adhesive and equal tightening of the sprocket bolts. This keeps the chain sprocket true with axle and free from wobble while spinning. With the bike is upside down spin the wheel and check sprocket for wobble. The chain can jump off the sprocket if the sprocket installation is done incorrectly. 

Standard Kit Sprocket installation:

Locate sprocket on axel hub with curved side next to spokes, shinny side in. Install rubber isolator to fit INSIDE the spokes and around axle. Install the split steel retainer plates next to the rubber isolator and insert 9 bolts.

1. Secure with 9 bolts compressing the chain sprocket to the spokes. Note: Rubber isolators may be needed on both sides of sprocket for chain alignment on some non-coaster brake bikes.

2. The Chain Sprocket on the Wheel must align within 1/2 cm to the Chain Sprocket on the Engine.

3. The wheel chain sprocket is mounted with teeth-out and dish-in next to spokes (bright chrome facing inwards). As in the example below:

Image result for bike kit rear sprocket backing plateImage result for bike kit rear sprocket backing plate

Note: If the chain touches the bottom bike frame tube to the left of the chain sprocket you may turn it bright chrome facing outwards but make sure the chain does not rub against your tires.

STEP 3 Fitting the drive chain

The drive chain can be easily shortened to the correct length. Special tools are required to remove and replace the master link when shortening the chain by removing links. Ideally, both your pedal drive chain and your engine drive chain should have the same tension.

A. Remove left rear cover plate from engine. This is the plate next to and under the clutch swing arm.

B. Use supplied spark-plug wrench to turn engine crankshaft sprocket to feed chain around it. Do not pry sprocket with a screwdriver or similar object.

C. Fit chain, measure and remove excess links to assure proper length. Be sure master link connection rides on the inboard side of the primary drive sprocket or interference of link and sprocket can occur. Proper chain length is when top chain has ¼ inch to ½“ deflection with the bottom side of the chain loop tight. 

D. Chain tension adjustments can be made by pulling rear wheel back if frame has straight slot wheel drop out. If both chains can be adjusted equally then installing chain idler on the wheel strut may not be necessary. At installer’s discretion the chain idler can be installed on either the pedal chain or engine drive chain. 

E. Install supplied chain safety guard by attaching to engine and wheel axle struts.

STEP 4 CDI Ignition installation: 

A) Mount CDI ignition coil on bike frame, close enough to attach coil wire to spark plug. Mount as far away from exhaust pipe as possible to avoid heat damage to semiconductors in CDI module.

B) Attach CD ignition coil wires to same identical color coded wires coming from engine.

Black to Black, Blue to Blue. Kill switch wires are Red/Yellow connect to Black double connectors, black is ground. Connect green wire to blue wires double connector wires from CDI BOX. White wire is for 6v headlight (if not using, tape off) (((( DO NOT GROUND))))

NOTE: White (ground) wire may be used for a small 6V LED  head light, taillight combination.  If you don't use the white wire please tpe off. Just connect blue to blue and black to black. Then just connect the kill switch wires yellow wire with red stripe plugs into the black double connector where the Magneto and CDI wires connect, the green wire hooks into the blue wires double connector.

C) Secure wires with a plastic tie straps. Route all wires away from engine exhaust heat.

Throttle & kill switch

CDI ignition coil

Spark plug, NGK BR6HS

Upgraded clutch lever 

Upgraded Carb with locking button

Clutch cable w/spring

STEP 5 Clutch cable installation and adjustment:

A) Install clutch lever to left side of handlebar and attach cable end to lever.

B) Squirt oil down the cable sleeve: Route clutch cable through the ball-mount on motor with the big spring around the cable jacket and ahead of the ball mount. The big spring serves as a cable heat shield.

C) Insert cable wire through small spring and route through clutch arm and attach brass cable-end and screw. Adjust cable tension to allow very slight play in arm. Handlebar clutch lever or twist clutch must be in the released or outward position to complete this operation

D) Activate lever a few times, and check clutch arm for slight free play: About 1/16“ free play is OK. Re-adjust if needed. Basics of clutch operation: The clutch lever pulls the cable that moves the clutch arm. In turn the clutch arm pushes a rod through the motor that pushes the clutch plate. ( similar to a car clutch.)Releasing the clutch lever engages the engine torque to the drive chain. The clutch allows engine to start, and engage or disengage engine torque to the drive chain. When the bike is in the pedal mode the handle bar clutch lever is locked inward in the catch notch. The bike then operates in default as it would without any engine. Periodic clutch adjustment is necessary to maintain efficient operation.

*NOTE: Cut off excess cable from clutch arm, before operation, to avoid possible interference with pedals, chain, your legs, etc..

STEP 6 Throttle and kill switch installation:

with kill switch

White (ground) wire may be used for a small 6V LED  head light, taillight combination.  If you don't use the white wire just connect blue to blue and black to black. Then just connect the kill switch wires to yellow wire with red stripe plugs into the black double connector where the Magneto and CDI wires connect, the green wire plugs into the blue wires double connector.


Operation of engine without stop or kill switch installed could result in personal injury if an emergency stop is required! The only alternate non recommended way of killing the engine is by releasing the clutch lever with bike brakes on and engine at slowest idle and wheel brakes on. 

Step 6A Carb Slide/ Throttle Cable Installation

Unscrew carb top, remove slide, needle, spring, and needle plate. slide carb top onto throttle cable, then slide spring on, then slide cable down the slotted side

of the slide, and slide cable into position cable into position. With the spring still on top of the slide insert needle and needle cover into slide, then move spring

in on top of needle cover. Insert slide into carb body with long slot on slide toward pin in side of carb. Make sure slide goes all the way down, if it does not make

sure you have the slot side of the slide facing the pin in side of the carb.


Image result for installing throttle cable on carb slideImage result for installing throttle cable on carb slideImage result for installing throttle cable on carb slideImage result for installing throttle cable on carb slideImage result for installing throttle cable on carb slide



STEP 7 Fuel Tank installation:

A) Attach fuel petcock to tank. Use Teflon tape to seal threads. Careful not to strip threads.

B) Mount tank on bike top crossover frame with two supplied brackets and nuts.

C) Attach fuel line from tank to carburetor.  *NOTE: Filters are contained in the petcock and in the carburetor inlet. If engine runs poorly clean the valve filter as residue from the tank may have clogged it.  It is recommended to upgrade to an in line filter eventually.  These are found at any motorcycle or automotive shop.


Gas and Oil Mixture for Fuel ratio:

The engine is a 2 cycle design; therefore, a gasoline/oil mixture is necessary. During the break-in period (1st gallon of fuel), 8oz. per gallon the ratio is 16 parts gasoline to 1 part oil. After the break-in period, the ratio can increased to 32 parts gasoline to 1 part oil, 4 oz. per gallon of fuel. Synthetic oil specially made for 2 cycle engines can also be used although a high quality standard 2 stroke oil is fine.

Break In:

An engine cylinder with piston requires break-in time: A rich oil mixture ensures rings will seat and bearings wear -in: Note: As `wear–in or break-in occurs power will increase. Seized pistons due to improper oil mix are not consider warranty:


Remember safety first: Wipe up any spilled fuel. NEVER fuel a hot engine or smoke while fueling. This could result in sudden fire, personal injury. Always move your motorized bike at least 10 feet from any fueling area before attempting to start it. Never leave the tank fuel cap off after fueling as rain water will contaminate the fuel and cause engine failure.

Starting procedure:

1. Open the fuel valve. Small lever pointed down with fuel line is in the open position.

2. Depress the small round cap plunger, (Tickle button ), to prime carburetor. Located on left side of the carburetor next to the idle adjust screw. One or two times is enough.

3. Lift choke lever to the upward position. This is the small lever on the right side of the carburetor. All the way Up the choke is on. All the way Down the choke is off. Move progressively downward to off position during engine warm up period. 

4. Pull the handlebar clutch lever inward, to disengage the engine from the rear wheel.

5. Pedal; (down hill if possible for first start) A mid frame bike wheel stand is helpful to start the  engine in place.

6. Let out the clutch lever all the way out and continuing to pedal. The result is a direct engine hook up with the rear wheel via chain and sprocket and the engine will now start spinning, Pedal until motor starts. Accelerate slowly at first..

7. Twist throttle to increase speed, reverse twist throttle to decrease speed. To stop,  disengage clutch and apply brakes. To accelerate, pedal and release clutch while opening throttle.

8. Adjust choke to the smoothest engine running position. 

9. After warm up push choke lever all the way down. If engine races too fast, or too slow,  pull clutch lever and lock in the notched catch, stop and adjust engine rpm.

10. If the rpm needs adjusting, turn the idle adjust screw (left side of carburetor) in or out slowly to obtain the proper idle speed of about 1400 rpm +/- 100 rpm To correctly break the engine in, Do not exceed 15-20 mph or 30 min. continual running for the first 50 miles during engine brake in. Engine will develop more power after break in.

11. To stop the engine, push Kill switch and turn off gas valve at tank. Turning off the gas will prevent fuel from being siphoned from tank.  Warning Note: Never leave the tank gas valve in ”open“ position“ when engine is not running or the bike is in storage.

12. After or before each ride check all mounting fasteners, including hd. bolts, axle and brakes.

13. Warning Note: Engine lock up or piston seizure due to improper gas / oil mixture will not be covered by factory warranty. This the responsibility of the owner / operator to make sure the gas and oil is mixed correctly.




*Clutch Adjust Nut

1. How to Adjust Clutch if signs of slipping or squealing are encountered :

A) Disengage clutch by pulling handle bar clutch lever inward and lock into catch lock. 

B) Remove right side engine clutch cover and remove small locking screw on center *Clutch Adjust Nut.

C) Pull clutch arm on left rear engine inward. Back off *Clutch Adjust Nut ¼ turn counterclockwise.

D) Release clutch lever and check for slight clutch arm 1/16“ free-play on opposite side of engine. Readjust *Clutch Adjust Nut as required to get required 1/6“ clutch arm free play.

E) Tighten *Clutch Adjust Nut on clutch plate clockwise until just snug.

F) Then re-install small locking screw in outer edge of *Clutch Adjust Nut.

G) Good idea to place a small gob of grease at gear mesh area. Use grease sparingly! Then replace cover.

H) Squirt light grade oil down clutch cable sheathing to reduce friction and make for easy lever pull.

2. Carburetor

After every 5 hours of operation check the adjustment of the mixture screw by rotating screw clockwise until seated and then rotate screw 4½ turns back counterclockwise. Depending on dusty riding conditions, clean air filter every 5 to 20 hours of operation by removing the filter cover to access the screen and element. Wash element with a degreasing agent such as Simple Green™ or Purple Stuff™. Be sure element is completely dry before re-assembly.

IMPORTANT: If engine runs poorly clean tank shut off value filter. 

3. Spark Plug BR6HS

Remove spark plug and inspect for excess carbon build up. Clean, re-gap to .028- .034 of an inch if necessary. Check plug after every 20 hours of operation. New spark plugs are available from your selling dealer. Be careful using aftermarket spark plugs as heat range and threads differ greatly.

4. Exhaust system

After 50 hours of operation check exhaust pipe for excessive oil and carbon build-up. Be sure to use supplied support strap to secure exhaust muffler to a solid anchor point on bike frame or engine.

Note: A engine that runs poorly can be due to a clogged up muffler.

A) Remove exhaust pipe cap by loosening the retaining screw.

B) Pull cap and baffle out of pipe.

C) Clean with degreaser, rinse and dry.

D) Re-assemble *NOTE: Excessive periods of low speed operation, idling or leaving fuel petcock in the ”on“ position during shut down periods may cause the pipe to become clogged with unburned fuel.

5. Chain

A) Every time bike is ridden check the tension of the drive chain by:

B) Rolling to bicycle forward to remove slack from the bottom of the chain.

C) Find the center and push downward on the top of chain while measuring the deflection.

D) Tighten chain if deflection is more than ½ inch.

6. Head Bolts

Tighten all fasteners after each five hours of operation. Most important to check Cylinder head bolts : Tighten in a X pattern to 8 to 9 ft/lb. using a torque wrench. A two piece cylinder and head design engine requires head bolts be kept tight. Important: Check head bolts before each and every long ride, vibration can cause them to loosen and blow a head gasket.

Caution: Do not over torque or head bolts may break off. ( Twisted or broken head bolts due to over tightening is not covered by warranty. ) 

7. Right side gears 

Remove cover plate and keep small amount of heavy grease on gear train. Do not over grease as leaks will occur and also may adversely affect clutch operation. Regular greasing will help reduce gear wear and keep gear train quiet.

8. Left side drive

Routinely pack grease in the shaft hole behind 10T sprocket and also in cover bushing hole. This will also help deduce noise.


Proper use and maintenance is important for the continued enjoyment of your Bike Engine. This product has been manufactured to strict quality control standards. For customer assurance there is a 30 day Warranty starting from the date of original purchase from an authorized dealer:. Warranty approval is subject to factory inspection and only the defective part or parts will be replaced, not the complete kit.