CRF450X Cylinder Head Rebuild Extreme Duty BeCu Seats CrN Ti Intake Valves

Description

This is Fastheads extreme duty endurance head package for the X.  Proven endurance by many top Baja teams. This rebuild, upgrade and
modification
is performed on your head.  You get our famous Beryllium intake seat package mentioned below plus upgraded Chromium Nitride Coated Titanium 36mm intake valves vs the stock 35mm, same as the R.  The larger valve size works great with open air boxes and less restricted mufflers.  Desert conditions with dry sand, dust and silt finds its way into the motor a lot easier compared to groomed watered motocross tracks.  The CrN PVD coated intake valves on the Beryllium Copper intake seats is the longest wearing set-up available to date.  Outwears Stainless Steel valve kits by serveral times without the power loss.
Call for additional info and current ETA's.
Our popular CRFHP2 Package
includes machining out the stock intake seats and installing new Beryllium Copper alloy Seats.  These seats are 100% compatible with the lightweight OEM and aftermarket Titanium valves and outwears heavier stainless steel valves on stock seats.  Our prices are a bit higher because we use only high dollar race proven alloys that absolutely wear and transfer heat better than any other metal.  If you what to maintain maximum power you have to use Titanium valves as originally designed.  If you have decided to go with steel valves and heavier springs for wearability (which we sell in our ebay store) you will loose more power than you can gain back from porting or cams.  This service also includes replacing the exhaust guides with Bronze Manganese.  To keep the cost down we only replace the intake seats and exhaust guides because this is what normally wears in the CRF's.  The exhaust seats don't wear as fast because they use steel exhaust valves for lateral strength needed due to the rocking action of the rocker arm.  This motion, heat and original metal wears the exhaust guide prematurely and usually needs replacing in order to cut a concentric exhaust seat.  Cutting the exhaust seat with a high flow multi angle seat profile is included.  Also whenever guides are replace the centerline is never the same and the valve will not seat unless the guide and the seat face are concentric.  The exhaust and the intake seats are then blended (a form of porting wear it is most critical) into the runners up to the guide.  This is the critical area that creates 90% of the flow restrictions.  We like to make sure our service is perfect so we also include removing and installing the valves vacuum testing to check quality.
OUR GUARANTEE
(you will get our general head service
free
with this package for life if it ever needs it!
The problem and solution:
The intake valves wear out prematurely in the CRF's because the seat material is not compatable with the OEM Titanium valves.  The stock powdered metal seats are abrasive, transfer heat poorly and tend to corrode much faster than the high tech Beryllium Copper seats.  Once the shim size is reduced more than 2 sizes the thin protective coating on the valve is diminished and wear accelerates at a much faster pace.  If the valve is not replace immediately it rounds out the seats.  If new valves are installed on the rounded seats they will wear out even faster than the original. The original fix was to replace the valves with the 40% heavier Stainless Steel which are more compatable with the stock seat material and heavier springs to control the valve.  It reduced the time between adjustments but also reduced the power by up to 2hp and reved slower plus put a strain on the other parts of the valve train including the stock seats.  OK for trail riding but not the ideal setup for racing at higher RPM.  Honda and all the other motocross manufacturers use Titanium for this reason.  Honda's CRF Unicam is a great design utilizing less space and weight but does have one shortcoming.  The exhaust uses a rocker arm that puts a slight lateral rocking action on the exhaust valve stem which requires a stronger valve stem.  This is the only reason they use steel exhaust valves.  Unfortuetly this rocking action wears out the exhaust guides extremely fast making it near impossible to cut a concentric seat face.  The exhaust valves don't seem to loose their adjustment but do corrode and pit requiring the seat face to be cut.  We use Stainless Steel race valves with a super slick Nitride coating and the Bronze Manganese guides with tighter tolerances that cool and self lubricating which slows the wear process.  The stock exhaust seats are more compatable with steel and stainless steel so we don't replace them unless they have been cut to deep or have decayed on the OD.
New Head 99 you can have all this installed into a new R head.  If you want to send in your complete head with cams, lifters, rockers etc we will adjust your valve shims for another .  A complete port and polish job is another 5 when done in conjunction with the above service.
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:  Fastheads 1141 E 540 N #6, Saint George, UT 84770
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.  Brent Kirk has raced and has been involved with the technical aspects of engine building for the last 39 Years.
On Apr-05-08 at 17:49:47 PDT, seller added the following information:
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