1980 Mugen ME125 W1

 The first Mugen ME125-W1 sold in the US. It was a works bike that anyone with $4000.00 could buy. It was on par or better than any factory works 125 in 1980.

On January 6th 1980 at Saddleback Park in round 1 of the CMC “Golden State Series,” Johnny O’Mara with a broken foot, got the holeshot up the long start hill and finished second overall to factory Kawasaki rider Jeff Ward. This was an amazing feat as Johnny had broken his foot just a week before in a practice session. What was equally amazing was the bike that Johnny was riding. It was an all white water-cooled works 125 designated the Mugen ME125W1.

The bike looked as if it was from twenty years into the future. It was completely hand made with a beautiful space-age looking fiberglass gas tank, hand welded white frame, a tiny all red water-cooled engine and works Showa suspension just like on the works Honda’s. The Mugen was stunning to look at; it was as trick as any works bike from any factory team and stole the show wherever it went. A few weeks after the CMC Saddleback race at another event at Indian Dunes, it was announced by Mugen president Hirotoshi Honda himself that the bike would be for sale.

Mugen was a company in Japan owned by Hirotoshi Honda who was the son of the founder of Honda, Sochiro Honda. Mugen Co. Ltd. began operations in March of 1973 by developing FJ1300 engines based on the Honda Civic engine for use in formula racing in Japan. In February of 1976 Mugen announced they would expand into the motocross market and by 1977 they were selling engine power-up kits for the CR125 and 250 Honda. In February of 1979 the first complete Mugen racers, the air-cooled ME125RZ and the ME250RZ went into production.

Although Mugen sold through Honda distributors in Europe, American Honda did not want to sell Mugen through their dealer network. So, Mugen USA Co. Ltd. was formed in August 1979 with Al Baker accepting the position of Director of US operations. To promote Mugen in the US it was decided to field a one rider team and compete in the 1980 125 nationals as well as other selected high profile races. Al Baker selected local So. Cal 125 pro Johnny O’Mara to be the man and a 1979 Mugen ME125RZ was shipped over for Johnny to compete on.

While all of this was going on, plans for an all new water-cooled 125 Mugen were underway. The bike would be state of the art in everyway. The only production parts on the all new Mugen would be the lower end of the motor and the wheel hubs. Nearly everything else except the works Showa suspension would be new and produced in house at the Mugen factory in Japan. Mugen was no stranger to works bikes, throughout the years they were contracted by the Honda factory to build many parts for the Honda RC works bikes. In 1979 Honda actually contracted Mugen to build a supercross RC250. The bike was designed by Honda and built by Mugen and only two were built.

The 1980 ME125W1 would be the first full factory works bike ever offered for sale to the public and anyone with $3995.00 could buy one.

The chassis featured excellent frame geometry and suspension components that were state of the art. In designing the frame, reduced flex was a major goal and to achieve this, the frame tubes that make up the engine cradle were purposely wrapped very close around the engine to minimize frame flex. The frame itself was constructed from chrome moly and careful engineering was used in the frame tube sizes and wall thickness. The frame was welded together using some of the most beautiful symmetrical beads of weld imaginable even exceeding the works Honda’s quality of the period. The result was a chassis that provided a very solid feel on the race track.

The swingarm is another masterpiece and is constructed of large box section aluminum and has the same quality of construction as the frame. A beautiful hand made chain guide was attached.

The suspension components are works Showa units just like on the works Honda’s with the forks using the latest cartridge design and exacting tolerances. Cartridge forks would not be on production bikes for another year and even then, the quality control on production parts vs. works parts wasn’t even close and neither was the performance.

The Mugen engine started with a stock CR125 Honda lower end and received a Mugen chrome bore water-cooled top end with a sand-cast clutch cover that housed a crank driven water pump. This was connected to the single radiator that went over the frame backbone and was connected by a series of aluminum tubes and hoses. The whole water-cooling system was very compact and out of the way. The engine was fed with a 34mm Kehin carburetor and the exhaust is a Mugen designed pipe and silencer. All combined to produce an astonishing 27 HP at 11,000 RPM. The ME125 was a very fast motorcycle.

The gas tank, shrouds, side panels and front number plate were all made from very high quality fiberglass finished in white gel-coat. The front number plate and shrouds were designed to draw air into the radiators and then exit through the contours in the gas tank that acted as an air-duct. The tank itself was slim and tall to hold enough fuel and provide an ergonomically efficient design. The entire bike was slim and very easy to move around on.

The Mugen ME125W1 was a complete package that provided performance at least as good as anything else including the other Japanese works bikes of 1980. At $3995.00 it was about four times the price of a production 125. This was a lot of money but compared to the other Japanese works 125’s it was a bargain.

The Mugen ME125-W1 was also used in Europe by the works Honda Team to save cost. Mugen made a red version for Europe.

Terry Good’s Comments:

The first time I saw the Mugen ME125 was at Indian Dunes on the International track early in 1980. My wife and I went there as spectators and we got there during practice. As we were watching, along comes this guy all dressed in white on an all white bike that looked like it was out of the movie “Star Wars.” The guy was absolutely hauling as he went by down a long whooped out straight. You could feel the ground shaking as he hit the whoops flat out and in complete control. The bike even sounded different than the others too. I noticed it was Johnny O’Mara on the bike and watched him until he was out of sight. Totally blown away by what I just saw, I just waited for him to come by again and when he did, he pulled off the track and went into the pits.

We ran over to find out where he went and finally found his pit. When we got there, there was already a crowd gathered and inside his roped off area was the bike. To this day I remember the first time I saw it, it was unbelievable. That bike looked so exotic and so far ahead of anything I had ever seen. I just kept starring at it trying to figure everything out. Nothing like this had been built before. Johnny was a great up and coming rider as I remember him on a Suzuki the year before but the crowd was there to see that bike.

Al Baker and Tom Halverson were working on it while Johnny was sitting on a lawn chair and then there was this other Japanese guy that was part of the entourage. I knew he was part of it but wasn’t sure as to what capacity. He came over by my wife and I and was standing there for a moment so I started asking him questions about the bike. He then introduced himself as Hiro Honda and began answering all the questions I had about the bike. After a while I asked him if they would be for sale and I was sure he would say no. His response was “Yes, we are going to sell them exactly like this one.” When I asked when, and how much he said “They will be $4000.00, we will be taking deposits starting tomorrow of $1000.00 per bike and they will be delivered in three Months.” I had no idea how I was going to come up with the money but I told him I will take the first one. We shook hands, he gave me his card, Johnny won the overall that day and I called the next day and ordered the bike.

The bike featured in this feature is the bike I ordered that day. After many delays and getting lost in the port of Long Beach for about two weeks, it finally showed up about six months later. When I went to Al Bakers shop to part with practically every dime I had and take delivery, I walked into the front office and there it was. After waiting three extra months, countless phone calls and the secretary offering me my money back because of the delays, the moment was overwhelming.

I went right from Al Bakers shop to my favorite test track and did a moto on my YZ Yamaha first and then gassed up the Mugen. I had been waiting and dreaming of this moment for over six months. Once out on the track the difference between the Mugen and the Yamaha was incredible. I had never imagined a bike that did everything so well. It felt much more solid and firm on the track, very precise. The front forks absorbed everything without a whimper. I remember seeing bumps and not feeling them. It cornered like it was on rails. For the first time on the hard Southern Californian adobe, berms were an option. And then there was the motor. It was the fastest 125 I had ever ridden by a mile. It had great roll on and an over rev that just kept pulling and never seemed to fall off the pipe. The YZ that was fresh and in great shape felt like an out dated worn out bike after riding the Mugen.

In my first race, the bike was drawing so much attention; I knew everybody was watching me because of the bike. I choked big time and did lousy on a great bike. In the second moto I got a bad jump off the line but all the way up the start hill the bike was just pulling like a freight train, I just kept up shifting. The front end was about six inches to a foot off the ground all the way to the first turn. I ended up getting the holeshot and just pulled away after that.

After three races on the Mugen I was involved in a car accident that put me out of riding for over a year and the Mugen got an early retirement. Today it sits as it did almost 30 years ago and has a total of about 5 hours running time. It is the first Mugen out of a total of five sold in the US. I am very surprised that they only sold that many as any aspiring pro on the national circuit would instantly have had equipment on par with anything out there including the factory teams.

There were a total of five Mugens sold in the US, at least one of them went to Europe. Mine was the only one sold in Southern California. One went to the San Jose area to a kid for his 16th birthday. Another went to Texas and the others went back east. Today there are more Mugens than were ever built. Most are built out of parts, some even having fake frames. - Terry Good

With only about five hours running time since new, this Mugen is probably the most original example in the world. 

 Nothing on the chassis has been touched since new. Even the tape holding the gas tank dampers to the frame is original.

Back in 1980 White Brothers made me this trick intake Boost Bottle when they were all the rage.

1980 Mugen ME125 Photos

Johnny O’Mara’s comments:

I was selected to be the Mugen factory rider by Al Baker. Al had just become the Mugen distributor for the US and Mugen wanted to have a presence at the nationals. They had all the team colors and uniform designs picked out to match the bike and give a very professional appearance at the races. We picked up the crate that had my two125 bikes in it and we went to Al bakers shop in Van Nuys California to uncrate them. I had no idea what to expect or what the bikes might look like but we knew they were going to be water-cooled.

After uncrating the bikes and getting the first glimpse, I was in total shock. The bikes were so trick and so advanced it was ridiculous. I never saw anything like that before. Wherever we went with them people were checking them out, it was just so cool just to be around them and have them in my garage.

When I first tried the Mugen out, I couldn’t believe how good it was. It wasn’t just show, it performed too. It was like riding an F-1 car compared to anything else. It was crazy. The bike was never lacking anything to the other bikes including the works bikes. In fact our Mugen was considerably better than the 1980 factory Honda RC125 at the time. It seems they were playing a little bit of catch up especially in the handling department. The Mugen was a complete package and a great benchmark. The bike also drew a lot of attention and more people started to follow my career as a result of the Mugen.

The bike was fantastic the way it came and very hard to improve on but we did get some special cylinders from Japan to use. Hiro was really into all the trick stuff and it really showed in the craftsmanship of his bikes and parts.

At the first 125 national at Hangtown, I got the holeshot and led for about 20 minutes and then I started to get tired. I was young at the time and still learning and wasn’t up to speed yet for the 40-minute motos but it was more of my inexperience than the bike at that time. Shortly after that, I was involved in a car accident and missed a few nationals but I got better in time for the USGP at Mid-Ohio. I really wanted to do good at that race because I missed some of the nationals. I had a lot on my shoulders because I was the flagship guy and a lot of attention was placed on me because of the bike too. Everybody was watching everything I did. I knew I had to do everything right that day to win and I did. I won the Mid-Ohio grand prix and I won against the best in the world. That was an awesome experience and a feeling that I remember to this day.

We were a factory team in a way but we were sort of off to the side of the Honda team. They included us in their pit area, but for the most part we were new to the factory team status so we were sort of just winging it. Mostly it was me, Al Baker, my mechanic Tom Halverson, Diamond Don and Hiro Honda when he came in from Japan to see how his team was doing. He took the whole US operation very personal and was very happy with the success we had here.

I remember the 1980 season and riding for the Mugen team more than any of the other years in my career. It was very special. I was very honored to have been selected to ride for them and I feel I didn’t let them down in their debut even though they were only here for a short time. To have Mugen as my launching pad to start my career was a huge benefit. The bike got a lot of attention wherever we were and even after almost 30 years it is still one of the most famous bikes in history and that alone says a lot. - Johnny O'Mara

O'Mara at the 1980 Mid-Ohio USGP. The very jersey he is wearing is in this collection below.

Johnny O'Mara's race worn jersey from the 1980 USGP at Mid-Ohio


Kurt Maneval took these three photos O'Mara with a Polaroid camera just before Johnny handed him his jersey. Kurt has donated the jersey to MXworksbike.

Happy time in the Mugen pits.  Johnny looks like his historic victory hasn't sunk in yet. Kurt Maneval photo

Johnny's upset victory on the white Mugen at Mid-Ohio, would go down as one of the most celebrated victories in motocross history.

Detail Photos


    • The motor uses a stock CR125 lower end with a special sand-cast clutch cover for the water pump. This bike has the optional 36mm bored to a 37mm Mikuni. A 34mm Kehin was stock. The optional mikuni really let the bike rev on top end. The aluminum case screws are from a works OW25 motor that I had back then.


    • The hand made brake pedal gave a very positive feel compared to anything else of the day. Notice how the frame wraps around the motor so tightly. Hiro Honda told me that this was designed this way to reduce frame flex. It worked. All the misc. drilling and titanium bolts were added by me in 1980. Did it help?....Of course not! I still have all the original steel bolts that came with it.


    • Front and rear hubs are stock Honda items. The axles and spacers were special machined items. The bikes did not come with white paint on the forks. They came with a clear coated aluminum finish.


    • The one off aluminum swing arm has got to be one of the nicest made on any bike, it is simply a work of art. The welds are just beautiful. The brake rod came pre-bent to create a progressive feel. The aluminum torque arm on this bike was made for me by a friend who owned a machine shop.


    • Rear tire is a Dunlop K290. It worked real good on the Southern California tracks. Stock was a Bridgestone M23. That is the original stand that came with the bike.


    • Almost all of the hardware on the rear was handmade (wheel spacers, axle adjusters, misc. nuts & bolts etc.) The chain guide is a very strong two piece aluminum unit.


    • Front forks are works 39mm Showas with knurled tubes and triple chrome plating that greatly reduced stiction. The performance was fantastic. The sliders are aluminum and they provide 300mm of travel. Later Johnny O'Mara had magnesium sliders on his Mugen. You could tell by the ridge on the front and the back of the slider. These were the same forks found on the Works Hondas in 1980.


    • Rear shocks are works Showas made just for this bike. These are the original shocks that came with the bike. Notice the hand machining on the bottom photo. The hot set up was to use Ohlins for a 1980 RM125. I did use those and yes they worked better. The Showas were very good but the rear end kicked a little too much. The Ohlins cured that problem.


    • The air box is a very large fiberglass unit that draws its air from under the seat.


    • Front numberplate, Radiator shrouds, Gas tank and side panels are all made from hand laid fiberglass. The Gas tank is contoured in the front to keep the air flowing thru the one piece radiator.


    • This aluminum pipe runs up the front downtube. It is the water passage way connecting the radiator to the cylinder head. Notice the way the Gas tank is formed to allow the pipe to go thru. A lot of thought went into designing this bike.


Historical Photos