Honda CR500 KPR "Race Spec" Cylinder Porting Service (1985-2001)

Turn your CR500 into a 70+ HP Legend.

Two Strokes Only is proud to be the exclusive online partner for Keith Peterson Racing (KPR). When you purchase this listing, your cylinder is ported directly by Keith Peterson—the "Wizard" himself—using the exact specifications that set the all-time dyno record at Kaplan Cycles.

As proven on the "Kaplan America" channel, this porting specification unlocks the hidden potential of the Honda CR500 engine, delivering a strictly measured 72 Horsepower at the crank (64.8 HP at the rear wheel) on the test bike.

The "Dyno Record" Formula KPR doesn't just grind away metal; they scientifically reshape the intake and exhaust ports to maximize flow velocity where it matters most. Unlike "hill climb only" builds that are unrideable on a track, this porting spec is engineered for Motocross and Woods dominance.

Key Performance Characteristics:

• Massive Mid-Range: Generates over 60 HP between 4,000 and 6,000 RPM.

• Rideable Power: Retains strong low-end torque (40+ HP right off idle) for getting out of corners and technical sections.

• Top-End Overrev: Pulls hard all the way to peak RPM.

Critical Component: The Cylinder Head

Porting alone is only half the battle. To achieve the compression and combustion efficiency needed for these power gains, your head must be matched to the porting work. You have two excellent choices:

Option A: Stock Head Modification (Included in Service Price!)

• The Value: Send us your OEM stock cylinder head along with your cylinder. KPR will machine the squish band and dome to the exact volume and compression required to match your new porting specification—this custom machining is included in the service price.

• Perfect for maximum performance while maintaining the factory look.

Option B: Upgrade to the TSO Billet Head (Premium Option)

• Purchase our TSO Billet Cylinder Head (available separately or as a bundle).

• Features a built-in Compression Release Valve, making starting your high-compression 500 as easy as kicking a 125—saving your ankle and your kickstart gears.

• Superior cooling passages and interchangeable domes allow you to fine-tune for different fuels.

Recommended TSO Upgrades

To replicate the reliability and rideability seen in the video, we recommend these TSO components:

1. TSO 1/2" Reed Spacer (Torque Optimizer)

• In the video, this spacer was critical for shifting the powerband into the meat of the mid-range. By increasing crankcase volume, it smooths out the hit and adds "tractor-like" bottom-end torque.

2. TSO "High-Flow" Billet Exhaust Flange

• Stock flanges leak and crack. Our Billet 304 Stainless Steel flange is O-ring sealed to eliminate the infamous "black splooge" and is precision-matched to the exhaust port of your newly ported cylinder for zero turbulence.

Service Includes:

• Complete disassembly and inspection of your cylinder.

• Precision KPR Race Specification porting (Intake, Exhaust, and Transfer ports).

• Port chamfering to prevent ring snagging.

• Modification and machining of your supplied stock cylinder head.

• Final finish and cleaning.

Compatibility:

• Fits all Honda CR500 Liquid Cooled cylinders from 1985-2001.

How It Works:

1. Purchase this service listing.

2. Print your order confirmation.

3. Ship your clean, bare cylinder AND your stock cylinder head to the address provided in your confirmation email.

4. We perform the "Wizardry" and ship it back ready to rip.

bore/stroke engines will vary but will see massive improvements over stock.

WATCH: The KPR Ported CR500 Sets a New Dyno Record