1977 YAMAHA YZ125

FULL FRAME-OFF RESTORATION • MATCHING-NUMBERS ENGINE & FRAME • WHITE BROTHERS SUSPENSION • DG HEAD • BUILT MOTOR • VINTAGE RACE READY

Here is an opportunity that simply does not come around very often: a spectacular 1977 Yamaha YZ125, fully restored from the frame up and upgraded with some of the most desirable period-style performance equipment you could put on one of these machines.

This is not just another restored vintage motocross bike. This YZ125 has been built into what amounts to a period-inspired works-style racer, combining the legendary Yamaha monoshock chassis with upgraded long-travel suspension, a completely rebuilt and performance-modified engine, a DG cylinder head, White Brothers aluminum swingarm and rear shock, and numerous fresh components throughout.

It absolutely rips.

With only approximately one hour of riding time since completion, this machine is equally suited for vintage competition, a serious Yamaha collection, museum display, or the ultimate centerpiece for a motocross enthusiast's garage or man cave.

MATCHING-NUMBERS 1977 YZ125

The motorcycle retains its original matching engine and frame.

The serial number is exceptionally low: #1305, placing it among the earlier-production examples from the 1977 model year.

Nearly five decades after these motorcycles were built and raced hard, finding an original matching-numbers example with a frame worthy of a complete restoration is becoming increasingly difficult.

This one survived remarkably well.

The underside frame rails are especially impressive. One side is virtually pristine with no significant dents, while the opposite side shows only one small imperfection — exceptional condition for a vintage motocross chassis of this age.

COMPLETE FRAME-OFF RESTORATION

This YZ was stripped down and comprehensively restored from the frame up.

Restoration work included:

• Frame stripped and refinished in automotive-quality gloss black

• Engine completely rebuilt

• Engine cases refinished

• Engine covers refinished

• Cylinder removed, cleaned and professionally finished

• Cylinder bored and ported

• Aluminum components cleaned and restored

• Fork lowers polished

• Triple clamps restored and refinished

• Exhaust modified and refinished

• Braking system serviced

• New bodywork where required

• New controls and cables

• New tires and tubes

• New chain and sprocket

• New air filter

• New fuel lines

• Fresh fluids

• Hardware replaced wherever necessary

The result is an extremely clean, tight and professionally presented motorcycle.

BUILT 125cc TWO-STROKE ENGINE

The original matching engine has undergone a complete rebuild and substantial performance preparation.

The cylinder was removed, cleaned, bored and ported, then intentionally left in its natural aluminum finish for a factory-race-bike appearance.

One of the standout pieces is the desirable period-correct DG cylinder head.

The DG head provides the unmistakable vintage racing appearance while contributing to the engine's performance package through revised combustion-chamber characteristics, increased cooling area and higher-performance specifications compared with the stock configuration.

Additional engine upgrades include:

• Performance porting

• Rebuilt top end

• DG performance head

• Modified expansion chamber

• Short aluminum performance silencer

• Carburetor jetting matched to the engine combination

• New air filter

• New fuel lines

• VP race fuel setup

• Six-speed close-ratio transmission

The engine is extremely strong for a vintage 125.

Power comes on aggressively when it enters the powerband, and the combination of the modified cylinder, head, exhaust and jetting gives this YZ considerably more performance than a completely stock 1977 machine.

WHITE BROTHERS ALUMINUM SWINGARM

One of the most valuable and visually distinctive components on the motorcycle is the White Brothers aluminum swingarm.

The original 1977 YZ125 used a conventional painted steel swingarm. This period performance upgrade is substantially larger, stronger and more exotic than the stock component.

The White Brothers setup includes:

• Aluminum swingarm

• Extended geometry compared with stock

• Custom axle arrangement

• Custom axle adjusters

• Period-style chain guide

• Spring-loaded chain tensioner

These components were expensive racing upgrades when new and are increasingly difficult to locate today.

WHITE BROTHERS LONG-TRAVEL REAR SHOCK

The rear suspension has also been substantially upgraded with a White Brothers long-travel shock featuring a remote reservoir.

Locating the reservoir away from the engine reduced heat exposure and was serious race technology for the period.

Combined with the aluminum swingarm, this gives the motorcycle substantially greater suspension capability than the standard production bike.

1980 YZ125 FRONT FORK UPGRADE

The front suspension was upgraded using a later-model 1980 Yamaha YZ125 fork assembly, dramatically improving travel and performance compared with the original 1977 setup.

Front-end restoration and upgrades include:

• 1980 YZ125 forks

• New fork seals

• Fresh fork oil

• Restored triple clamps

• Polished fork lowers

• New Michelin front tire

• New inner tube

• New front fender

• New front number plate

• New Renthal handlebars

• New Renthal crossbar pad

• ODI grips

• Quick-adjust lever

• New lever perches

• New control cables

The completed suspension package offers roughly 11.8 inches of travel at the front and approximately 11.25 inches at the rear, giving this machine a dramatically more capable stance and feel than a stock '77 YZ125.

WHEELS, BRAKES & DRIVETRAIN

The motorcycle retains its period Yamaha wheels, including an original rim that still carries its DID identification decal.

Additional chassis work includes:

• Matching Michelin tires

• New tubes

• Refreshed braking system

• New gold drive chain

• New sprocket

• Restored original footpegs

• New shift lever

RESTORED BODYWORK

The bike presents beautifully from every angle.

It features:

• Original Yamaha fuel tank

• Fresh Yamaha graphics

• Bob "Hurricane" Hannah-inspired lightning bolt graphics

• Championship-style number-one plates

• New front fender

• New rear fender

• New side panels

• Restored seat

• New seat cover

The finished appearance captures the look of a late-1970s factory motocross machine.

THE HURRICANE HANNAH ERA

The late 1970s were a legendary period for Yamaha motocross.

Bob "Hurricane" Hannah became synonymous with Yamaha's rise to motocross dominance, and the yellow-and-black Yamaha competition machines remain some of the most recognizable motorcycles of the era.

The YZ125 combined light weight, Yamaha's revolutionary monoshock suspension concept and an explosive two-stroke engine with a close-ratio six-speed gearbox.

This restored example takes that original formula and pushes it considerably further with period racing upgrades front to rear.

Park this motorcycle next to a photograph of a stock 1977 YZ125 and the transformation is obvious.

OVER $10,000 IN RESTORATION LABOR ALONE

Building a motorcycle to this level today requires an enormous amount of time.

A comprehensive restoration of this caliber can easily consume 60–70+ hours of professional shop labor.

At our current professional shop rate of $150 per hour, that represents approximately 9,000–10,500+ in labor alone, before accounting for the motorcycle itself or its rare performance components.

There are also thousands of dollars in specialty and replacement parts represented here.

More importantly, many of the components on this bike simply cannot be ordered new today.

Finding a genuine vintage White Brothers swingarm, period shock, DG head, suitable later YZ forks and a solid matching-numbers foundation can be considerably more difficult than paying for the restoration itself.

This motorcycle is already finished.

RIDE IT OR DISPLAY IT

There are two ways to own this motorcycle.

Race it.
Put a capable vintage racer aboard it and this should be an extremely competitive machine in the appropriate vintage drum-brake motocross class. The motor is strong, the suspension has been substantially improved and the motorcycle is ready to be enjoyed.

Or:

Preserve it.
Display it as an extraordinary piece of Yamaha motocross history.

With its restored condition, matching-number foundation and collection of hard-to-find period performance components, it would look equally appropriate in a private collection, corporate display, motorcycle room or museum.

CONDITION

This motorcycle has approximately one hour of total riding time since restoration.

It starts, runs and rides extremely well.

The engine is exceptionally strong, the transmission shifts properly through all six gears, the suspension feels excellent and the motorcycle has been thoroughly sorted following completion.

It is presently displayed on the third floor of the New England Motorcycle Museum and is available for inspection.

INVESTMENT-GRADE VINTAGE MOTOCROSS

The surviving supply of quality 1970s motocross motorcycles continues to shrink.

Most YZ125s from this era were raced hard, modified, damaged, parted out or simply discarded decades ago.

Finding one with:

• Matching engine and frame

• Extremely low production serial number

• Complete frame-off restoration

• Built engine

• DG head

• White Brothers aluminum swingarm

• White Brothers remote-reservoir shock

• Later long-travel YZ forks

• Excellent frame rails

• Fresh tires, controls, bodywork and drivetrain

• Minimal time since restoration

…is extremely difficult.

This motorcycle represents the era when two-stroke motocross development was moving at an incredible pace and Yamaha was at the forefront.

It is fast.

It is beautiful.

It is exceptionally rare.

And most importantly, it is finished and ready to enjoy today.

SHIPPING & FINANCING

We can arrange licensed, insured, enclosed transportation directly to your door anywhere in the continental United States.

Financing options may also be available to qualified buyers.

For additional information, purchasing details or to arrange an inspection, contact:

Kaplan Cycles / New England Motorcycle Museum
Junior: 860-454-7024

Visit KaplanCycles.com to see our complete inventory of classic and modern motorcycles.

Serious buyers are encouraged to act quickly. Restored, highly modified period YZ motocross machines of this caliber rarely become available.

God Bless America.

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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.