ELSINORE, due respect for the lineage
• Timeline on Airbox
• Green on the Tank!
2010 Model Features
Plenty of room - For 2010 the ignition module once located on steering pivot behind the front number plate is moved to the large airbox.
The Rectifier/regulator and Capacitor originally located on the left frame spar are moved as well. All aforementioned components are now located within the airbox utilizing the O.E. brackets and insulators. This move centralizes a few pounds of mass, allows ‘high use’ components to neighbor each other and also protect the expensive electronics from crashes, mud and power washers. Removal of the sub-frame is only slowed a few seconds by three multi-connectors. It is still silly/easy compared to a new EFI bike.
CR250r – A little ‘sweat equity’ and ingenuity results in the left frame spar void of the rectifier/regulator, capacitor and related brackets that were welded to the frame. Also removed is the wires that traverse the frame up to the steering head. Both hollow frame spars are filled with structural foam to limit resonance frequency throughout frame and handlebars.
Unsprung weight = bad, CR250r Caliper carrier assembly is lightened over 300grams and finished to look better than production. Stainless steel button head fasteners are used throughout including both rotors.
2010 Cylinder features new Transfer port trajectory and improved exhaust valve design. (This is the second cylinder. After a few base cuts and port jobs the first cylinder is a fine paper weight or ‘a retired Guinea pig’) Visible is the 2010 RC Valve cover featuring Yellow Lexan® inspection window and sleek stainless Button head fasteners including stator cover. Also note – reliable stock expansion chamber.
Gearing is testament to how the 2010 edition runs. The stock CR250R required a tooth or two added to the rear sprocket due to the poor low-end. This engine utilizes an additional tooth on the countershaft. Due to its new-found torque and RPM ceiling this bike equals more go – less toe, each gear lasts substantially longer. Also shown in photo is aggressive wide foot pegs, thermal coated carburetor body, modified V-force reeds, shortened sub-frame arms, shimmed swing arm pivot, lightened O.E. shifter and painted HONDA inlay.
Additional Engine modifications include;
• Cylinder – stock transfer port trajectory error fixed, PowerPlant Porting© modified from mouths to ceilings to exits, exhaust port and bridge modified, Base machined, Exhaust valve stop silicon coated.
• Piston – skirt radius relieved and finished.
• Piston pin – custom ground for less weight.
• Connecting Rod – small end relieved and rod finished.
• Crankshaft re-balanced specific to new lightweight piston assembly. All Lobe voids stuffed with epoxy to a flush surface.
• Exhaust Valve (RC Valve) – welded and machined to create a truly functional valve to port relationship for much improved low-end performance.
• Cylinder deck – converted to O-ring for superior thermal sinking and low cost O-rings versus Honda steel gaskets.
• Stator Plate – adjustable, static timing marks added, two advanced, two retarded.
• Clutch – All aluminum drive plates for less gyroscopic forces/weight, Honda Blue clutch springs and stock springs @ 3 to 3 ratio. Filled with fresh $3 Type F ATF every ride. Clutch basket and inner cover – surface textured accordingly to know laws of Tribology
• Silencer – Original Honda unit shortened, repacked and resealed.
• Airbox Boot – internally re-shaped and textured
• Carburetor – Bell re-shaped including removal of unused circuit flange, venture bored .040”. Diet – Sunoco Race fuel, Jetted appropriately @ sea level and 40:1 Yamalube R©
• Reed/intake manifold – V-force assembly installed and port/matched to Honda intake manifold.
• Coolant is EngineIce and cap is a polished 16 lb Stainless steel American made Stant.
Additional 2010 chassis changes;
• Forks; O.E. with rider specific spring rate change, disc brake guard bosses removed and finished.
• Shock; O.E. with rider specific spring rate change.
• Linkage; packed with low drag grease.
• Wide Stainless steel IMS pegs
• Sub frame – rear lowered ½ inch.
• Cycra® White Stadium plate
• Throttle Jockey® HRC seat cover with ½ taller.
• Side Number plates – Factory located vents enlarged and finished with Honda Red foam to defuse air and water.
• Fuel Tank – Fuel anti-slosh foam inside, whole tank lowered 1/4 inch.
• Clutch lever – O.E. lever machined and bearing installed and shimmed for no side play, end hollowed out.
• Throttle – requires only one cable as this engine doesn’t suck as hard as a four-stroke.
• Kevlar Grips glued and wired
• Calipers – front and rear hand grinded to remove all redundant weight and flap wheel finished
• Rotor, front – 2009 CRF wave pattern.
• Chain & sprockets – Black renthal and black chain as to not draw attention to these otherwise ugly parts.
This all cost a “few” dollars, relatively speaking. These modifications are more expensive then a simple once-over but all modifications here proved less expensive then a typical four-stroke rebuild or the depreciation hit post-showroom.
What was once a quick bike is now Fast. What was once a simple bike to own is more simple. What was once a cheap and reliable bike is more-so. Thanks for allowing me to share my project.
• John Nicholas for showing my steed, www.twostrokemotocross.com
• Mark, Roger and Joe at In-Motion-Grafix,
• Sandra @ SVS Fine Art for the good taste,
• Ron, Greg, Doreen and Sam at BrowardMotorsports.com
• PowerPlant Engines, firstname.lastname@example.org
• Willie at WMImx.com for great suspension service.