1980 SUZUKI RM400

Stunning Frame-Off Restoration

433cc Big Bore With DG Exhaust, Works Performance Shocks & Much More;

"The ultimate air-cooled open-class Suzuki twin-shock motocrosser."

Feast your eyes on this absolutely stunning 1980 Suzuki RM400, a no-expense-spared frame-off restoration of one of the most iconic big-bore motocross machines of the golden era. If you're looking for a museum-quality vintage motocrosser that's equally at home on display, at MX Rewind, or ripping around your favorite motocross track, this is the one.

This isn't just any RM400.

The engine has been professionally rebuilt and upgraded to 433cc, transforming an already legendary open-class motocrosser into an absolute holeshot monster. Combined with a beautifully restored and tuned chassis, modern suspension upgrades, and a handcrafted DG exhaust system, this bike delivers the look, sound, and performance every vintage motocross enthusiast dreams about.

We have restored more RM400s than anyone in the U.S.A., and we only start with the best possible foundation. This motorcycle retains its original matching engine cases, frame, swingarm, fuel tank, wheel set, and major cycle components. The frame rails are exceptionally clean, the engine cases are beautiful, and the bike was the perfect candidate for a complete nut-and-bolt restoration.

Engine & Performance

The engine was completely dismantled and rebuilt during the restoration process.

Highlights include:

• Engine bored and built to 433cc

• Carburetor completely rebuilt

• New jets and tune specifically for the DG exhaust system & big-bore conversion

• New spark plug

• Fresh transmission oil

• New fuel petcock

• New fuel filter

• New fuel line

• New carburetor drain lines

• Twin Air air filter

The bike starts easily, runs cleanly, and pulls like a freight train. It has massive low-end torque, enough to loft the front wheel almost at will, yet revs freely and pulls hard through the entire powerband.

Whether you're launching off the gate, blasting through sand whoops, or simply reliving your glory days, this RM delivers the kind of raw, brutal two-stroke power that made open-class motocross legendary.

One of the visual centerpieces of the build is the full DG exhaust system with Polished DG aluminum silencer, Hand-finished, machine-polished and Custom heat-blued finish.

The silencer isn't chrome—it is polished aluminum that has been painstakingly finished and the pipe was refinished & heat-colored to create a stunning factory-race-bike appearance.

The polished ignition cover emblem, engine mounts, hardware, Swing Arm, Fork Lowers and countless detail pieces throughout the motorcycle showcase the level of craftsmanship that went into this build.

Back in 1980, the RM400 was already one of the best-handling open-class machines available.

This example is even better.

Upgrades include:

• Modern Works Performance rear shocks

• Fully rebuilt and polished long-travel air-assisted forks

• New fork seals / New fork oil / New fork boots / New sliders

• Steering head bearings serviced and renewed

The Works Performance shocks dramatically improve rear-wheel control and comfort compared to the original units.

With approximately 15 pounds of air in the forks, the bike sits tall, tracks straight, and floats over rough terrain remarkably well. The suspension is significantly better than what riders had available in 1980.

Chassis Restoration

The entire motorcycle was stripped to the bare frame and rebuilt from the ground up.

Restoration highlights include:

• Frame refinished in original gloss black

• Triple clamps vapor honed

• Fork lowers machine polished

• Swingarm machine polished

• Original wheel set restored and polished

• Original rims in good condition

• Original hubs restored and refinished

• Magnesium brake backing plates restored

• New chain slider / New chain rollers / New chain adjusters

• New hardware throughout

• Original chain guide restored

• Original swingarm bolt polished

• Pegs refinished

• Running gear vapor honed, polished, or refinished as required

The attention to detail throughout the chassis is exceptional.

Both wheels were fully serviced and restored.

• New Dunlop D952 front tire

• New Dunlop D952 rear tire

• New tubes / New rim strips

• Front brake restored

• Rear brake restored

• Original rims polished / Original spokes polished

The bike is ready to ride, race, or display.

Every detail was addressed during restoration.

• New front fender

• New front number plate

• New graphics kit

• New Renthal handlebars

• New Suzuki crossbar pad

• New ODI Ruffian grips

• New shorty clutch lever

• New shorty brake lever

• Pro Restored original fuel tank

• New tank graphics

• New breather hose

• New seat cover

• New rear fender

• New side panels

• New mounting hardware throughout

The controls feel tight and precise, exactly as they should on a properly restored vintage motocross machine.

This motorcycle received:

• 50 hours of professional shop labor

• Labor rate: $150/hour

• Total labor investment: $7,500

• Parts investment: Over $2,500

Total restoration investment exceeds $10,000, not including the cost of the motorcycle itself.

Historical Significance

The RM400 represents one of the greatest air-cooled open-class motocross motorcycles ever produced.

These bikes were raced by motocross legends, including Roger DeCoster, and remain among the most desirable twin-shock motocross machines ever built.

For many riders, the RM series defined an era of motocross when lightweight handling, massive two-stroke power, and simple mechanical excellence ruled the sport.

This motorcycle is presented in exceptional restored condition.

It starts easily, runs strong, shifts properly, rides beautifully, and presents as one of the finest restored RM400s you'll find anywhere.

Whether your goal is:

• Vintage motocross competition

• MX Rewind events

• Collection investment

• Museum display

• Weekend riding enjoyment

Shipping & Contact

We can arrange professional nationwide enclosed transport directly to your door.

Questions are welcome.

Kaplan Cycles
Rockville, Connecticut

Call Jr. at 860-454-7024

Vintage motocross bikes restored to a standard that speaks for itself.

Bid with confidence,

God Bless America!

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”

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

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.

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.