Other complete packages.  

$399 Stainless trail package.

$699 Extreme TiBerChrome package

New Heads Assemble with valve train starting at $599 

$140 CRF Valve job only on bare head.   

$175 General head service, valve job (no parts included) assembled with your parts and vacuum tested.

$35 Valve shim adjust with above work.  Must send cam, lifters, rockers etc.

$1395 Complete Motor Rebuild.  Parts and labor, bottom and top end. 

$79 Hotrod valve shim kit with the perfect thin feeler gauge set for adjusting valves. 

WE SPECIALIZE IN MOTOCROSS HEAD REBUILDING FOR ALL BRANDS. 

Please note: Modern valve faces should never be cut our you will loose the hard facing and treated surfaces. For this reason we only assemble with new valves. You can either supply yours or we can supply at a reasonable price. We offer a wide variety of valves in stainless or titanium, OEM and Manganese guides, guide seals, gaskets, and valv seats to match your needs. If you want an endurance or the Ultimate race head we can build it. Dealers and race teams are welcome. We use the new race developed and proven Rottler SG7 seat and guide machine specially designed for accuracy and tooled for the power sports industry.   

With the economy in shambles, hanging on to your current machine and keeping it in prime condition is the new standard.  We can keep you running and updated!      

The before and after pictured head had a valve had broken off, the old seats were machined out and oversized copper alloy seats were installed to repair the damage.  The gouges and damaged areas were welded and re-surfaced.  This can get expensive but its sometimes better than loosing an expensive port job and the head is better than new.        

Please check out our ebay store for motorcycle tools, rebuild kits and rebuilding services.     

Send your heads and engines to:  Racers ER / FastHeads.com 1141 E 540 N #7, Saint George, UT 84770

Brent 435-668-7776    

We operate one of the largest mail order style service for complete engine, transmission and head work for off road race bikes.  It's our specialty so we can save you money and headaches.  See us at the WORCS races and other events around the west.   Brent Kirk has raced and has been involved with the technical aspects of engine building for the last 39 Years. 

Racerser / Fastheads.com is based out of Saint George, Utah.  435-668-7776. 

WORN VALVE SEATS HAVE TO BE RE-CUT OR FACED IN ORDER TO DECREASE NEW VALVE WEAR AND MAINTAIN PERFORMANCE. MOTOCROSS HEADS REQUIRE NEW MACHINING TECHNIQUES. Specialized machining techniques have been developed in order to cut seats in current motocross and other small engine race style multi valve heads. This is everything you need know in order to grasp the concept of how and way valve seat concentricity is critical in performance, wear and reliability and why old school methods of seat cutting do not work.

All valve seats are cut by installing a pilot shaft in the guide in which the cutting tool centers and revolves around. The seat has to be accurately cut horizontal and vertical to the centerline of the valve guide. Concentricity is how perfect this measurement is. Poor concentricity will let one side of the valve land on the high side of the seat face first. Depending on the severity of the seat face offset the valve may always be open on the low side or the valve may flex or slide to center from the force of the valve spring. Guides wear oval front to back and may let the pilot move in the same pattern which can also create poor concentricity on the seat radius. Imagine now, how non-concentric seats can affect the ability for the valve to seal under pressure, how it increases valve wear, how it decreases the ability for the valve to transfer heat to the seat and how the valve stem being flexed every time the valve closes can create it to break. The following is a description on why it is nearly impossible to maintain concentricity using old machining methods on newer race heads.

1. Valve stems and the guides are much smaller in diameter. From 7-8mm to 4-5.5mm. The smaller pilot shaft needed to fit in the guide decreases its ability to withstand flex thus allowing the cutter to follow the old seat face.

2. The distance from the top of the guide to the seat face has increased due to a much larger port which has allows the pilot to flex even more.

3. Some race seat face profiles requires the cutter to cut more surface at one time along its cutting edge which create more force against the pilot.

Modern machining equipment has been created to adapt to the pilot flex problems. Most early four strokes were low rpm utility engines and had large enough pilot to enable the use of hand operated cutter and grinders with some degree of accuracy. They would run and start even if the concentricity was off compared to the tolerances required in race motors. Most motorcycle shops cut valve seats using these hand tools such as a“Neway cutter” and didn’t realize the need for perfect concentricity until their work immediately started to fail. Except for race technicians most mechanics don’t even know what a concentricity gauge looks like. One major cure was to use stiffer pilots made of carbide instead of tool steel to reduce flex. This still didn’t give us the concentricity requirements with hand operated cutting tools. The only way to make concentric cuts with small pilots is to perfectly support the pilot from the top and guide side. This requires the purchase of a $30,000 or more air float seat and guide machine. Not to many shops will spring for that type of equipment and most mechanics if they are educated on the importance of concentric seats and its effects on reliability will send them to a professional race machine shop that deals in small valve stem seat cutting.

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