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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 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:
Purchase this service listing.
Print your order confirmation.
Ship your clean, bare cylinder AND your stock cylinder head to the address provided in your confirmation email.
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
Compatibility
Fetching compatibility details...
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Customer Reviews
Overall rating: 4.9 / 5 from 58 reviews.
Shipping was fast, the product is great!
When you could still buy the shift forks from Kawasaki they came out of spec :-(
These are in spec and far better quality than Kawi's forks.
They are in the bike and vastly improved the shifting on this KX500 BEAST!!!
Thanks Luke!
Unfortunately, the gas cap got scratched during shipping,
but after a few friendly emails, the problem was resolved perfectly for both sides.
Friendly service, quick solutions, absolutely reliable
Top-notch shop👍
Everything I have received from TSO has been excellent, I was excited to see TSO had the pressure plate because they was the only ones , thanks for amazing products and service
Very well made pipe fits good have not been riding yet so don’t know if it leaks out two stroke oil like the stock one does we will see when it gets cool out for riding
Very quick shipping, and super pleased with the quality of this stator cover! The anodized black blends nicely with the satin black powder coat on my KX500 engine.
Quality parts!!! Very happy with what I received for the money!! Fit and finish is top tier. Also happy to support a company who is helping keep these two strokes alive! I will be back for more parts soon!
Bearings were a perfect fit. A couple of shaft bearings were on back order, which I reicieved shortly after a majority of my orders arrived. Quality of everything is immaculate I would certainly do business with Luke again. I honestly wish I could have purchased the billet cases for my kx500af build after seeing the precision on the covers and head. Highly recommend TSO
Haven't installed these parts yet but the maching and quality looks better than OEM. Looking forward on trying out their other specialized parts offered.
I ordered the case saver for my 98 kx250, the price of the TSO case saver was very close to the same as the original kawasaki one.
The difference is huge, The TSO case saver is made of stainless steel for extra strength and great looks.
Shipping and customer service was very fast and included mounting hardware.
First time I ordered from TSO, but it won't be my last.
Thanks TSO for offering a quality part and great customer service!
So the cylinder head is immaculate and performs perfectly with the decompression valve. Much much easier to start this 500cc 2 stroke. I just wish I the decompression valve was coming off the side instead of straight out the top. Decompression valve creates interference taking out the spark plug when everything is mounted and the bike is together. Purchased a new wrench to remove the spark plug and all is ok. Overall happy 😁