Motorcycle Valves & Valvetrain Parts

The valvetrain of your motorcycle is a mechanical assembly designed to regulate the operation of valves. It has to make sure that valves open up and close down at exactly the right moment allowing the air-and-fuel mixture to enter the combustion chamber and exhaust gases to escape from the engine. Just like in the majority of internal combustion engines, valves are opened when pushed by a camshaft. Double overhead camshafts operate the valves directly, while a single overhead camshaft actuates rockers connected to the inlet and exhaust valves. The timing chain or belt drives the camshaft which rotates synchronously with the engine crankshaft.

Double overhead camshafts allow for reduction of weight and elimination of the reciprocating mass of rockers thus speeding up the valvetrain. Depending on the type of your motorcycle, there can be two, four, or five valves per cylinder. The more valves, the more air and fuel can be delivered for combustion, the more efficiently the engine works. Typically, the inlet valves are bigger than the exhaust valves, or the number of inlet valves is higher than that of exhaust valves. The reason is that it is much harder to suck enough air-and-fuel mixture into the cylinders than to push exhaust gases out with the pistons.

Over the years of daily use and higher mileage, some coil valve springs can become weak or broken. If the spring does not close the valve when it is not actuated by the camshaft, the compression drops drastically. The same happens if the valve is not seating properly due to carbon deposits, bends, or excessive wear. On the digital shelves of our online store, you can find a wide assortment of high-performance valves made of hard-wearing, lightweight titanium. Their surface is hardened thanks to a CrN coating which also reduces friction. Besides a set of valves, the kit includes springs, retainers, spring seats, and valve locks.

Steel valves are much more affordable than their titanium counterparts which need to be replaced on a regular basis. High-quality Chrome Vanadium Steel valves are durable and can serve up to three times longer than their titanium factory-installed analogs even under some of the most extreme operating conditions. Besides, such valves allow you to avoid costly engine modifications offering rebuild options with new retainers, bases, and seals. Steel is heavier than titanium, so you need to use stronger valve springs as well. When choosing a valve set for your restoration project, make sure to get a kit with extra smooth stem surface for reduced friction on the guides.

High-quality valve stem seals must ensure perfect fitment, maximum service life, and optimal valve lift. They must withstand high engine temperatures while being impervious to aggressive oils, fuels, and gases. During their operation, valves bounce against their seats which wears their lips down. Springs force the valves to sink deeper into the motor thus reducing the distance to the camshaft. To compensate the distance in the valve gap, you may simply install another shim of different thickness in the valve end bucket, so you may want to obtain a proper valve shim kit. Visit our store to find premium-quality products offered at an affordable price.