4-Stroke Intake/Exhaust valve train components explained HONDA CRF, KAWASAKI KXF, SUZUKI RMZ, YAMAHA YZF 250/250F/450/450F

Motorcycles designed from a racing performance platform, will most likely have Tititanium  intake and exhaust valves. The misunderstanding the general public has  about Stock OEM valves is that they are the same quality and design specs as the aftermarket valve industry.  Stock OEM Titanium valves average about 75-95 bucks a piece. OEM valves cost less because they are 2-piece valve design. OEM's do this for cost reasons. The valve stem rotates as a plasma arc  welds the tulip to the valve stem. This is usually the weakest link  When valve train failure occurs, Stock OEM valves will break right at the weld spot. If you plan to purchase stock OEM valves, be prepared to break your motor down Titanium is the best suited material for valves. Unfortunately,  using OEM valves will cause you problems. This is commonly referred to as Planned obsolescence. The only solution to this is, having a fat bank account buying solid 1 piece Titanium forgings. Some 2007 models are fitted with Stainless Steel valves.

There are many reasons and variables why valve train failure occurs. Lack of maintenance, valve adjustments, infrequent oil changes, worn and fatigued valve train components.    As a general rule of thumb,  titanium valves should be replaced with every piston change.  Consult your service manuals for service intervals.

New 4-stroke dirt bikes rev at RPM's exceeding 13,000. This  plays a big part in the equation..  Worn out valve components or  using after market cams with higher lift and duration. Add into the equation, aggressive down shifting with over revving and you have got yourself a ticking time bomb. Frequent inspection of your valve train is your best bet. There will be a point, when your valve train will exceed service limits. Ignoring this problem is a ticking time bomb. The solution to a unreliable valve train system is installing stainless steel valves.. Installing one piece stainless steel valves will put reliability back into the valve train. Less valve adjustments, way more reliable. The popular aftermarket manufacturers of stainless steel valves are Faction MX, Ferrea, and Kibblewhite. There are a lot of misconceptions in the valve manufacturing industry. Of course, every manufacturer has there own method of making valves. But there are common fundamentals that they all share. Raw, Solid Stainless Steel and Titanium forgings come from other parts of the world. Cost of materials and material availability are the vital factors.  There are a handful of valve component specialized manufacturers in the world that keep the quality and pricing competitive. Consumers benefit from this in a very big way.  The cost of raw materials and labor to machine and surface treat engine valves  in the USA is overvalued.  Its to bad, we have the technology, yet we manufacturer off shore.

There are riders out there who claim, using stainless steel valves slows your bike down due to the weight differences between stock Ti valves and stainless steel valves.  Imtech Powersports has put this misconception to the test. We have tested a 250cc and a 450cc 4-stroke dirt bike.  Our Dynojet 200i dynamometer has given us results that does not warrant all the hype.  The RPM change is so little, that most riders, including racers on a semi professional level do not  notice..

The hype about using stainless steel valves and how they allegedly lose RPMs and horsepower is a bunch oh hot air.