Here is a nice motorized bicycle performance motor, completely gone through by Fred!

This one has a 40 mm stroke, balanced "speed crank".

The front mount is a narrow 1-1/4".

Here are the important features of this engine:

• 40 mm stroke "speed crank"
• 7.2 cc combustion chamber, center fire Fred Head with compression release installed
• Modified type A piston
• Stage 2 modified cylinder body with advanced timing
• CR Machine intake plenum with 19 mm spigot
• 15 mm SHA style carburetor fitted with .70 mm jet
• air filter
• .60, .65, .75, .80 mm additional jets
• Throttle cable
• Compression release cable and operating lever
• NGK B8HS spark plug
• 1- 1/4" width front mount

First, this motor is fitted with a Fred head that has a 7.2 cc combustion chamber volume which will allow you to run normal pump fuel (91-94) even if you are using a killer exhaust system.

The better the exhaust, the more power the engine will produce.

The cylinder body is a modified stage 2 version and is fitted with my unique intake plenum with a 19mm spigot.

This engine comes with a 15mm Dellorto SHA clone carburetor, factory fitted with a .70mm jet and low profile air cleaner.

Please note:

Do not use this engine on a bike that uses a spring loaded chain tensioner in the drive mechanism, unless a freewheel is used.

In order to obtain engine braking, the drive system should be single speed, rigid type.

A spring loaded tensioner used in this application would cause severe damage when the compression release is actuated.

If this engine is used on a bike equipped with a shift kit, operating the compression release while vehicle is in motion will cause the engine to shut off.

With a shift kit equipped bike, the engine cannot help slow the bike down because of the freewheel drive mechanism.

VERY IMPORTANT:

This engine is fitted with a balanced "speed crank". This crank has been tested and approved for high engine speeds.

I have tested a similar engine on my 26 inch test bike with a 30 tooth rear sprocket, and reaching high speeds is no problem.

In fact, I must reiterate that with this engine, you will be able to reach high speeds. This is my entry level race engine. More advanced engines will be available in the future, but are in the process of development.

 Please, for your own safety, wear protective gear and a real helmet, otherwise, you will be taking a big risk with your life!

Please read this important disclaimer:

I will provide the best technical support I can give, however there are no warranties for this engine.

This engine is designed for non road use,  and operating a motorized bicycle is inherently dangerous.

Because of this, the buyer is responsible for any damages or losses that may occur to themselves, others or property from the use of this engine.

Fred Chelminski or CR Machine will not and cannot be held liable for any kind of direct or indirect damage or loss that the use of this or other products may cause.