KX250F Intake Valve Seat Replacement Beryllium Copper A25 + Head Service EFI

Description

Many of the KX250F heads that we receive for service have crumbling intake seats as shown in the picture.  Small pieces of seat material fracture and fall out which can damage top end parts including the cylinder, piston and valves. This is more common in newer EFI models that may have run lean, hot or compression modified and is usually only on the intake side.  It is a good idea to check this area when doing a top end.  The fix is to install beryllium copper A25 alloy intake seats.
The price includes cutting out the old intake seats, installation, and then cutting all seat face profiles both intake and exhaust side.  These heads have very thin castings and installing press fit intakes seats disrupts the concentricity of the exhaust seats to guide the axis so they have to be re-cut.  Upon arrival your head is cleaned by soda blasting, fully inspected for all needed repairs, above repairs performed, adjust spring and stem heights as needed, professionally assembled and vacuum tested.
Pay only after we receive and inspect the head.
Please download our service request form at Fastheads and send with your complete head with valves.  Call us with any questions.  435-668-7776.
We sell the stock size BeCu A25 seats separately for a pair.  Please see our Ebay store for all our products and services.  We offer new heads or your head serviced and tested with upgrade Del West Ti or Kibblewhite stainless valves trains installed and tested in discounted packages.
FASTHEADS COMPLETE KX250F HEAD SERVICE PACKAGES WITH CUSTOM VALVE TRAIN INSTALLED!
Fastheads deals exclusively in motocross cylinder heads and valve train components for all brands.  We machine, repair and service worn or damaged heads with the latest high tech equipment designed for high RPM multi valve heads.  Old school methods of valve seat re-facing or grinding will not work on these new heads!  Our primary goal is incredible reliability and reduced valve wear while maintaining stock or more power.  We do this by using
compatible
alloys, DLC type valve coatings and precise machining for perfect valve to seat concentricity.  We offer economy, trail, and full on race options with porting depending your needs.  Whenever a 4-stroke has tuning or compression issues it is generally a problem with the valve train not sealing or improper valve clearances.
We offer a complete KX250F head service (Not part of this
advertisement
offer but total labor is reduced) includes and all new upgraded CrN PVD Coated Titanium valves for extended valve life and full power, OEM springs and viton seals.  We remove the old valves, soda blast away carbon and make a complete inspection.  The seats are then machined using our race proven Rottler SG7 seat and guide machine.  We cut a concentric seat profile that reduces valve face wear.  The head is then assembled with CrN Ti valves, valve springs, guide seals, and vacuum tested for quality.  We re-use your spring base locators, retainers and keepers if in good condition.  04-06 models are
updated
with newer intake springs, retainers and locators which also reduces valve wear, add .  Many of KX250F original seats crumble starting at the outside of the seat ring bore.  If this has happened or if the seats have been previously re-machined we will call with an estimate.  We can usually repair slightly seized cam journals for around .  We can adjust the valve shims for another .  Your welcome to  send your head for inspection and estimate prior to purchase.  Please fill out the work order on our web page.
Most KXF Motocross heads used for competition should be serviced every 60-100 hours for peak performance and reliability.
Factory teams inspect and rebuilds theirs every weekend of racing.
We offer many service packages in our E-bay store.  Here's a price menu.
5 general head service (GHS) soda blast head, inspect head for all needs, cut concentric seats, professionally install your valves, springs, seals etc.  Stem and spring heights are checked and corrected and then vacumm tested.
9 GHS + Titanium Del West DLC PVD coated upgrade valves, new OE springs and Viton guide seals.
9 GHS + Stainless Steel Kibblewhite Conversion using their spring kit. Not for racing, should be used for trail riding and lower to Mid RPM's.  2hp loss with stainless kits.
9 All Beryllium Copper seats and Bronze Manganese Guides installed.  Bare Head
4 minor cam journal repair includes polishing the cam bearing surface (bare head)
5 porting when done in conjunction with a service.  0 without service
9 New head fully assembled with upgrade valve train and vacuum tested.  Call
95 Complete top and bottom end motor rebuild.
High RPM small valve stem Motocross motors required specialized high tech valve seat machining equipment and skilled machinist in order to cut a concentric seat.  Most dealers, mechanics, race shops and automotive machine shops do not have this capability.  The result from a poor seat cut is hard starting, valve stems break and extreme wear on the valve face and guide.
We highly suggest staying with Titanium valves vs the installation of aftermarket heavy stainless steel valve kits that reduce output by 2hp, slows acceleration and peak RPM.  The use of Stainless require heavy springs that prematurely wears the stock seats.  All new dirt bike heads are designed to use Titanium for these reasons.  The seats need to be professionally cut (part of this package) or they will wear out any new valve.  3
to 5 day turnaround.
Machining Process:
Heads that produce this kind of HP, RPM and high thermal energy need special machining with very close tolerances for perfect concentricity.  We use the super accurate race developed Rottler SG7 seat and guide machine and cut all seat profiles with perfect concentricity to the guides centerline.  There are only a few race shops around the country including Racers ER / fastheads.com that can properly do a valve job on these new style MX heads.  You may want to read our article in Thumpertalk under engines to better understand the in these heads compared to general automotive.
Seat Blending:
This is basically porting where it is needed the most between the bottom of seat where it meets the casting up to the guide.  We take special care in producing a smooth unobstructed port job in this area for a lot better flow than factory.
Seat and Guide Replacement:
Beryllium Copper for increased cooling and major anti wear qualities when used with Titanium valves.  We replace worn or broken guides with Bronze Manganese for the same reasons.  It runs 9 to replace all guides and seats and cut seat profiles in a bare head.  We can usually fix for around slightly siezed cam journals and lifter bores for .
If you what to maintain maximum power you have to use Titanium valves as originally designed.  All current motocross engines use Titanium Valves for this reason.  If you have decided to go with steel valves and heavier springs for economical wearability you will loose more power than you can gain back from porting and cams.
If you want a complete port and polished head we charge another 5 when done in conjunction with the above service.
Please check out our ebay store for motorcycle tools, rebuild kits and rebuilding services.
Send your heads and engines to:
Fastheads.com
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.  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.
On Apr-05-08 at 17:49:47 PDT, seller added the following information:
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