2005 HONDA CR500 ALUMINUM FRAME CONVERSION

Stunning Brand New Frame Off Build, Insanely Fast!

Fresh New Engine With

MILLAR RACE ENGINEERING CYLINDER

There are two things you absolutely need before attempting to build a proper aluminum-frame CR500 conversion: a mint frame and an exceptional CR500 engine.

This bike started with both.

Take a look underneath it and you'll immediately see what we're talking about. The aluminum frame rails are exceptionally clean and the bottom of the original Honda CR500 engine cases is beautiful. The swingarm, front wheel and other original components show the same thing; Mint & Original.

From that foundation, Kaplan Cycles went all-in.

The result is a fresh custom aluminum-frame CR500 powered by a completely rebuilt CR500 Engine Loaded With Performance Upgrades Including the Millar Race Engineering Cylinder, fitted with premium suspension, controls, exhaust, wheels, brakes and one-off Kaplan Cycles graphics.

70 hours of professional shop labor at our current $150/hour rate went into this machine = $10,500 in labor plus more than $5,200 in new parts, for approximately $15,700 invested in the restoration and build before even factoring in the value of the CR500 engine and aluminum-frame core.

This is not a cosmetic restoration.

This is a serious, fresh, track-ready CR500 build.

MILLAR RACE ENGINEERING CR500 CYLINDER

The engine is the centerpiece of this motorcycle.

We had this Millar Race Engineering cylinder in inventory, we were saving it for the right build. Adam Millar is one of the most respected names in high-performance CR500 engine development, and his custom porting package is designed to deliver something far more important than simply producing a giant peak horsepower number.

It makes usable power.

Some highly modified CR500 cylinders can produce impressive dyno numbers but become difficult to ride on a motocross track. This Millar setup is different. It begins pulling extremely hard from lower in the RPM range than a stock CR500 and continues pulling beyond where the stock engine signs off.

The powerband is massive.

A professional motocross racer who rode this machine described it as the fastest motorcycle he had ever ridden.

Engine build includes:

• Fresh Millar Race Engineering performance cylinder

• Custom Millar Race Engineering porting

• Brand-new piston

• Brand-new piston rings

• New base gasket

• Modified cylinder head for increased compression

• Engine cases split and completely rebuilt

• Vapor-honed crankcases

• Brand-new crankshaft

• Brand-new connecting rod

• Brand-new crank bearings

• Brand-new crank seals

• Completely new clutch assembly

• New shifter seal

• New kickstarter seal

• Rebuilt water pump

• New water-pump seals and gaskets

• New engine gaskets throughout

• New engine seals throughout

• New engine hardware

• Rebuilt and polished kickstarter

• Boyesen Factory Racing ignition cover

• Boyesen Factory Racing clutch cover

• Boyesen reed valves

• Brand-new Twin Air filter

• Pro Circuit CR500AF expansion chamber

• Pro Circuit Factory Sound stainless/aluminum silencer

From the bottom of the crankcases to the top of the cylinder head, this engine has been Completely Rebuilt.

It is all brand new inside.

The engine presently has only three heat cycles and approximately Ten minutes of ride time following completion.

PRO CIRCUIT CR500AF EXHAUST

The bike is fitted with a genuine Pro Circuit AF exhaust system, specifically designed for CR500 aluminum-frame conversions.

The expansion chamber carries the AF designation and is paired with the matching Pro Circuit Factory Sound silencer.

It sounds exactly like a properly built CR500 should.

Deep, crisp and absolutely ferocious when it comes onto the pipe.

We run this machine on VP Racing race fuel, which is recommended due to the higher-compression cylinder-head configuration.

ALUMINUM FRAME & CHASSIS

One of the biggest factors in determining whether an aluminum-frame CR500 build is worth doing is the condition of the chassis.

This one was the right candidate.

The lower frame rails are exceptionally clean. The rails were polished and the remainder of the aluminum frame was carefully Scotch-Brited to restore its original appearance.

The original swingarm is equally impressive.

Chassis service includes:

• Polished frame rails

• Scotch-Brited aluminum frame

• Steering-head bearings inspected and regreased

• Swingarm bearings serviced

• Linkage bearings serviced

• All Chassis bearings and bushings inspected & lubricated

• Excellent original swingarm

• Extensive new chassis hardware

When you see clean frame rails, a clean swingarm and a clean original front wheel, those are all good indicators of the type of life a motorcycle lived before restoration.

This one started with excellent bones.

COMPLETELY REBUILT SUSPENSION

The suspension has been completely serviced front and rear.

Front suspension:

• Completely rebuilt forks

• New fork seals

• Fresh fork oil

• Pro Circuit red-anodized triple clamps

Rear suspension:

• Completely rebuilt rear shock

• New shock seals

• Fresh shock fluid

• Fresh nitrogen charge

• New shock bumper

The bike is ready to be ridden or raced.

FRONT END & CONTROLS

Everything the rider touches is new.

Up front you'll find:

• Brand-new Dunlop front tire

• New front brake rotor

• Completely serviced front brake system

• New front fender

• New front number plate

• Pro Circuit red-anodized triple clamps

• Brand-new Renthal Fatbar handlebars

• Brand-new Renthal crossbar pad

• New ProTaper quick-adjust clutch perch

• Gold quick-adjust clutch lever

• New clutch cable

• Brand-new ODI grips

• New fuel-tank breather

The controls feel exactly the way a freshly built motorcycle should.

WHEELS, TIRES, CHAIN & SPROCKETS

The original front wheel remains on the motorcycle and is in excellent condition.

The original rear rim had a slight imperfection, so rather than compromise the build, we replaced it.

The rear wheel now features:

• Brand-new Takasago Excel rim

• Takasago Excel spline-drive spokes

• Brand-new rear Dunlop tire

• Brand-new black rear sprocket

• Brand-new gold drive chain

• New chain sliders

• New chain rollers

• Excellent chain guide

The front tire still has its molding whiskers, and even the rear still has them around the sides.

IMS SUPERSTOCK FOOTPEGS

Like many of our CR builds, we upgraded the original footpegs to IMS Superstock pegs.

They're wider, stronger and provide substantially better grip and rider control than the original equipment.

BRAND-NEW SDG SEAT

The motorcycle is fitted with a complete new SDG seat assembly, including:

• New seat pan

• New seat foam

• New seat cover

ONE-OF-ONE KAPLAN CYCLES GRAPHICS

One of the details that truly separates this motorcycle from other CR500 conversions is the graphics package.

This is Kaplan Cycles custom graphic kit #113.

Every one of these graphics kits is individually designed for the motorcycle it goes on. The number-plate design, shroud layout and overall graphics package are unique to this bike.

There is not another CR500 exactly like it anywhere.

These graphics are produced exclusively for our builds with support from our graphics partners and are not offered for general sale.

If the new owner ever damages the graphics and needs another set, we can reproduce the kit specifically for this motorcycle.

Additional new bodywork includes:

• New radiator shrouds

• New side panels

• New front number plate

• New front fender

• New mounting hardware

COOLING SYSTEM

The cooling system has been thoroughly serviced.

• Radiators pressure-tested

• Radiators confirmed leak-free

• New cooling hoses

• Rebuilt water pump

• New water-pump gaskets

• New water-pump seals

• Fresh cooling-system service

Everything was addressed as part of the comprehensive build.

EASY-STARTING CR500

Anyone who's spent time around big-bore two-strokes knows that starting technique makes all the difference.

This CR500 starts exceptionally well.

Our cold-start routine is simple:

Turn the fuel on, lean the bike over briefly to prime the carburetor, bump the engine through to prime the cylinder, use the choke when cold, bring the piston just past top dead center, return the kickstarter fully to the top and give it one complete, committed kick.

For us, it starts first kick consistently.

Once warm, no choke is needed.

THE CR500 EXPERIENCE

There's really nothing else quite like a properly tuned CR500.

If you've ever ridden one on a fast national-caliber motocross track such as Southwick when the track is smooth, you already understand.

The engine doesn't need to be screamed.

It simply pulls.

Roll into the throttle and the bike feels like it's attached to a giant rubber band. Hills disappear. Straights become extremely short. The torque is enormous, yet this Millar engine has the broad power delivery necessary to actually motocross the motorcycle rather than simply create a dyno-sheet hero.

And when it comes to starts, very few motorcycles have ever been able to launch out of the gate like a properly tuned CR500.

Feed the clutch out, get it hooked up, drop the hammer and hold on.

This is the Motor of Doom.

ONLY THREE HEAT CYCLES SINCE COMPLETION

This motorcycle has essentially no time on the completed build.

Three heat cycles and approximately five minutes of riding up and down our driveway.

This is as close as you're going to get to buying a freshly built CR500AF without commissioning an entire build yourself.

OVER $15,700 IN LABOR & PARTS

Building one correctly is neither inexpensive nor quick.

This machine received just over:

70 HOURS OF PROFESSIONAL SHOP LABOR

At our current shop rate of $150/hour:

Labor Investment: Approximately $10,500

Plus approximately:

Parts Investment: $5,200

For approximately:

$15,700 IN LABOR AND PARTS

That does not include the acquisition cost or value of the excellent CR500 engine core and aluminum-frame chassis required to begin the project.

Anyone who has priced a professionally built CR500 aluminum-frame conversion knows what these machines cost to reproduce.

Newly built CR500 aluminum-frame conversions can easily enter the $20,000–$30,000+ range, with extensively optioned custom builds going considerably higher.

And perhaps more importantly, finding excellent CR500 engines and cases to start these projects with becomes more difficult every year.

COLLECTOR QUALITY — BUT BUILT TO RIDE

This machine could go in either direction.

Take it to the track and experience one of the most exciting motocross engines ever produced.

Or clean it, put it on display and preserve it as one of the most iconic two-stroke motorcycles of the modern era.

Either way, you're starting with an exceptional example.

CR500s have developed an enormous following.

This one has already had the expensive and time-consuming work completed.

Fresh engine.

Fresh suspension.

Fresh brakes.

Fresh tires.

Fresh controls.

Fresh drivetrain.

Custom graphics.

Premium aftermarket equipment.

And virtually no time since completion.

BUILD HIGHLIGHTS

• Honda CR500 500cc two-stroke power

• Aluminum-frame conversion

• Mint lower frame rails

• Excellent original Honda engine cases

• Millar Race Engineering cylinder

• Millar custom porting

• Higher-compression cylinder head

• New piston and rings

• New crankshaft and rod

• New crank bearings and seals

• Completely new clutch

• Vapor-honed crankcases

• Boyesen reed valves

• Boyesen Factory Racing engine covers

• Pro Circuit CR500AF pipe

• Pro Circuit Factory Sound silencer

• Twin Air filter

• Pressure-tested radiators

• Rebuilt water pump

• Rebuilt forks

• Rebuilt rear shock

• Pro Circuit red anodized triple clamps

• Renthal Fatbars

• ProTaper quick-adjust clutch assembly

• ODI grips

• IMS Superstock footpegs

• New Dunlop tires

• New Takasago Excel rear rim

• Excel spline-drive spokes

• New chain and sprocket

• New chain rollers and sliders

• Complete new SDG seat

• Custom Kaplan Cycles graphics package #113

• Approximately 70+ hours professional labor

• Approximately $5,200 in parts

• Approximately $15,700 invested in labor and parts alone

• Only three heat cycles since completion

• Approximately five minutes of ride time

READY FOR ITS NEXT OWNER

This CR500 has been built to a level that's becoming increasingly difficult to duplicate.

Great CR500 engines are getting harder to find.

Great cases are getting harder to find.

Great chassis are getting harder to find.

When you start with the right pieces and invest the time and money necessary to build one correctly, you end up with something special.

That's exactly what you're looking at here.

This motorcycle is fully built, sorted, tuned and ready for its next owner — whether that means a day at the motocross track or a place of honor in a serious motorcycle collection.

For additional information or to purchase the motorcycle, contact Kaplan Cycles at 860-454-7024.

Serious buyers are encouraged to call.

Machines built to this level don't come around often.

Vin - JH2ME10345M102198

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WHY SHOULD YOU BUY FROM KAPLAN? WHAT DO YOU GET?

“You are buying from the Kaplan Cycles Family. We are not just another big auction house. We are family-owned and operated and have been buying, servicing, and selling motorcycles since 1975. You will work directly with Ken Jr., Ken Sr., and/or one of the 30+ experts on our team. We provide museum-quality, white-glove concierge service from start to finish. Every motorcycle we sell is inspected, serviced, and supported by our team, and we stand behind it after the sale. You’re not on your own — we back what we build and what we sell.

With over 17,000 units sold and still 100% positive feedback, we are the best stress-free buying experience you can have. From the first call to delivery at your door, we will handle it all — because vintage motorcycles deserve support, and so do you.

With every bike we curate you get:
• museum-level inspection & preservation services
• every machine is professionally evaluated, serviced, & rotisserie detailed
• all critical systems are checked, adjusted, or renewed
• you get professional setup, tuning, and delivery prep
• done by the best experts in the industry — we ride and restore every day
• you get post-sale phone support
• you get white-glove, insured, always-enclosed shipping to your door anywhere in the country

You’re buying from Kaplan Cycles at the New England Motorcycle Museum, one of the largest vintage motorcycle collections in North America. Free museum tours and tickets are included with every bike sold. With every bike you purchase, a portion of the proceeds is used to support, continue, and improve the 501(c)(3) nonprofit New England Motorcycle Museum.

You don’t just win an auction — YOU are creating & helping to preserve motorcycle history, and you become part of our family, a Kaplan Cycles client for life.

We do not take new clients off the street.
We do not service bikes purchased elsewhere.
We only take new exclusive clients who purchase a motorcycle from us.

You get a guided purchase experience with, and from, the experts who care about the bike as much as you do. If there’s a problem, you don’t get ghosted. You call us — you will have our cell phone numbers — we will answer your call on weekends, and we will help make it right.

Auction platforms = listing only. No support. No accountability.

Kaplan Cycles = we stand behind what we sell.

You are buying museum-curated provenance. That means:
• expert evaluation
• documented condition
• professional presentation
• long-term preservation mindset

You’re not just buying a motorcycle — you’re buying a curated piece of motorcycling history.

From the #1 family in this business — Kaplan Cycles & the New England Motorcycle Museum.

Sincerely,

Ken Kaplan Sr.
12/28/2025”

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AUCTION TERMS:

All motorcycles & vehicles are sold as-is where-is.

Kaplan Cycles guarantees all motorcycles are as-described. Please read the entire description and watch the entire video before bidding.

A non-refundable deposit is due immediately on purchase. PayPal or Credit Card is accepted for the deposit.

Cash (In-Person), Card (+3% fee), or Wire Transfer are our only accepted forms of final payment.

Full payment must be made within 7 days of auction close.

Your motorcycle must be picked up within 30 days of auction close. 

Exceptions are made only for international buyers OR buyers who have ALREADY made transport arrangements with a third party.

If a motorcycle is purchased and left here for longer than 30 days without written permission from Kaplan Cycles it will be resold. In the case of a re-sale, the owner will be entitled to a refund less storage fees ($25/ day beginning 30 days from auction close) ONLY if the motorcycle was paid in full on-time within the auction terms.

We always describe our motorcycles as accurately as possible.

You are purchasing a classic motorcycle. Even in cases where a bike may be in good running/ operating condition, new problems & idiosyncrasies can arise over-time from sitting or regular use.

If you have an issue with the motorcycle you’ve received, contact us within 24 hours of delivery and before leaving feedback so that we can address your concerns.

It is important you have at least a basic mechanical knowledge before purchasing and operating a classic motorcycle.

Due to our backlog, we cannot perform any additional service work or modifications on your motorcycle after the sale (ie; adding a light kit, different tires, etc.)

We respond quickly between the hours of 9am and 5pm EST, Monday - Friday

For our fastest service please call Ken Kaplan Jr directly at 860-471-0192

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We will not charge out-of-state buyers sales tax.
Out of state residents will pay sales tax with their DMV. 

We are not a registering dealership. You will receive only the documents required to register your vehicle in your state.

In our listings, title status is always listed directly below the main description.

In some cases we will sell motorcycles without title or registration. In these cases we guarantee all motorcycles sold are free and clear. We will always provide a route to obtaining title. Generally in these cases, the motorcycle will be sold at a discount to accommodate expenses involved.

Documents are mailed via USPS priority mail with a tracking number. Please allow up to 14 days after payment in full for your documents to be processed and mailed.

Keys will be shipped with the motorcycle.

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Warranty:

All Motorcycles sold "as is, where is" and Kaplan Cycles does not warranty any motorcycle sold. No express warranty and/or implied warranty are made by Kaplan Cycles. No statements by us give an implied warranty.

SHIPPING:

SEND US YOUR ZIP FOR A SHIPPING QUOTE!
WE WILL MAKE ALL ARRANGEMENTS!

We have the best shipping contacts in the nation who will provide the FASTEST transport times, have a perfect track record, and are always insured and ENCLOSED! All motorcycles are shipped WHOLE (roll-on, roll-off). We do not offer a pallet or crate service.

International shipping specialist contacts are available! They will assist in ground freight, customs clearance, and ocean freight to your country. International buyers will be required to work directly with our third party shipping contacts.

We strongly recommend you insure your motorcycle at the time of purchase.

PICKUP:

We require a 24 hour notice prior to pick-up. Please call us at 860-454-7024 during office hours Monday – Friday 9am – 5pm EST.

We will provide ramps, a dock for loading, and assistance to load for free.