1980 Suzuki RH80
1980 AMA 250 National Champion
Kent Howerton's 1980 250 championship RH80 was a present to him for winning the national championship. Here it sits against the turquoise waters of Lake Michigan.
The 1980 Suzuki RH80 featured here was the last of the Japanese twin shock works bikes. Instead of going down in flames to the new single shock bikes, it went out in a blaze of glory. This is the bike that Kent Howerton used to win the 1980 AMA 250 national championship.
The bike itself is a very well balanced package with excellent frame geometry providing excellent cornering and straight-line stability. At first glance it is obvious that the bike is a no-frills all out works bike. The front and rear suspension complements each other as the twin shock rear suspension system was fully developed at this point. It should be noted though that Honda was experimenting with a linkage system attached to the swingarm on their twinshock works bikes right before they switched to the single shock Pro-Link system.
The frame and swingarm on the RH80 are made very ridged and provided a very solid flex free chassis. The components are very well made and feature massive gusseting in the key areas.
A set of works Kayaba 43mm front forks with machined lower sliders made from aluminum are held in place by a beautiful set of billet aluminum triple clamps. The front forks are complemented by the state of the art Ohlin shocks that were serviced by Kent Ohlin throughout the 1980 season.
While Honda and Yamaha were improving their braking power with double leading front brakes, Suzuki chose to increase the surface area of their brake drums by making huge sand-cast magnesium full width hubs. By making the hubs so wide, the open part of the hub was weakened and aluminum rings were pressed on to stiffen up the weak side of the hub.
The RH80 engine is a sand-cast magnesium engine with a design that is very typical to Suzuki during this era. There are several innovations on this motor to aid in performance such as the very easy and positive clutch pull is achieved by routing the cable right through the center case so there is no flex what so ever. To aid in cooling the cylinder fins are so large, they actually wrap around the front frame down tube. A very expensive sand-cast magnesium Mikuni carburetor saves just ounces. Suzuki’s philosophy was attention to all the little details would equal a better overall race bike.
Mechanic Greg Arnett and Kent Howerton Pose with the championship RH80.
1980 Suzuki RH80 Photos
Kent Howerton's comments:
My 1980 RH250 Suzuki twin shock bike was the result of an on going development process that began when I first signed with Suzuki and we began to work on the 1978 works bikes. The development never stopped as we would use our setup from the end of 1978 to start the 1979 bike and then that bike developed into the 1980 bike.
Before the season began, I went to Japan to test the 1980 works bikes and to select the different options for the rest of the team. The 1980 frame geometry was pretty much established by the time I got there so I tested different combinations of triple clamps, pipes, engine configurations, suspension settings, handlebar bends etc. I also had to figure out options for Darrel Shultz and Mark Barnett to try out in the states so they could set their bikes up for themselves. We had virtually every part interchangeable with other options so you could just about set the bike up everyway imaginable. In 1980 we even tested carbon fiber mufflers and wheel rims.
Many times the engineers would be competing with each other on various designs. There might be two engineers each with a different design for the rear suspension set up. During testing, sometimes the engineer with the most seniority would really lobby for his design to be chosen but I always chose the one I thought was best. It really got political at times.
Major changes to the bikes were always decided and made in Japan before the works bikes went into production and only minor changes were made in the states. Suzuki had over 20 engineers building and working on the works bikes.
Once the testing was done in Japan, they would then go into production building the works bikes and the optional parts that were chosen in testing. After the bikes were built, they were sent to the states and then the entire US factory team would test and set their bikes up to each riders own personal preference.
For 1980 the bikes didn’t get to the states until right before Hangtown so we didn’t have the time needed to set them up properly. I remember at Hangtown my forks felt like they were jackhammers. I was coming down this little left hand downhill with a right turn after and the forks were so bad I couldn’t get the bike lined up for the rut and fell because of it. I had over a minute lead and was able to pick it up and still win but I had some more testing to do.
The next week I went to Carlsbad to set up the suspension and Kent Ohlin helped me set up the rear shocks for the next race at Saddleback. This was a big improvement but the shocks remained better than the forks the whole year, those Ohlins were really good.
Riding this bike vs. a stock RM250 was like night and day. There was no comparison at all. The works bike ran better, the suspension was so much better, it was so much lighter, and everything about it was better. I would practice on RM production bikes during the week and get used to those and then when I went to the races, I would race the works bike and it would take until the end of the second moto before I got used to it.
We practiced with production bikes for two reasons. One was the cost. They were very expensive and there weren’t very many of them. Reason two was the technology. Suzuki had a policy that a Suzuki employee had to be in charge of the bike at all times. I was not considered an employee, I was a contracted rider. The mechanic could not let the bike out of his sight, so I couldn’t take the bikes out by myself to a practice track and train. They were very protective of those bikes and each rider only got two bikes for the year anyways.
Midway through the season, I had the championship about won, and we were at the Mt. Morris 250 National in Pennsylvania. We had just taken delivery of the new prototype Full Floater earlier in the week. While riding in practice on the twin shock bike, there was a section that jarred my back every time I went through it> I was in a lot of pain from a back injury, so I thought I would try the new bike. Going through the same section on the new Full Floater, there was no pain. The bike absorbed that section much better than the twin shock bike did. At that point I was convinced that the new bike was better than the twin shock bike. I really wanted to race the new one but Suzuki was against it because it was untested. The bike was so much better that I told them I wouldn’t race unless I could use the new one and Suzuki agreed. I one the race that day on the new Full Floater and used it to finish out the season.
I did get to test a works Honda earlier in the season at Indian Dunes in California. I met Roger DeCoster there for a secret test session at a time when Honda was trying to get me to sign with them. My initial reaction to the works Honda was that the rear suspension wasn’t as good as my Suzuki but there were many things about that bike that were better like the motor. The Honda had a better motor and was way faster than my Suzuki. I asked DeCoster what if anything I could change on the bike if I were to sign with them and he said they would do anything I wanted to make the bike right.
I was comfortable at Suzuki and didn’t know the Honda that well and usually I don’t like to change environments but I liked the idea that they would change the bike any way I wanted. I decided to tell Honda team manager Gunnar Lindstrom I would sign with them. They would have a contract for me to sign at the first Trans-USA race at Lexington Ohio.
At Lexington the Suzuki boss Tosh was also there to resign me with Suzuki. They were offering me less than Honda but still I started to feel uneasy. I was a complete zombie walking around the pits because I didn’t know what to do. In practice I could hardly ride and luckily during the race, my reeds got sucked into the motor because my mechanic forgot to tighten them. So my bad performance was masked by a mechanical.
Later that day, I went to Gunnar and said the decision has been bothering me and I just don’t feel comfortable riding for Honda. I said I told you I would and if you hold me to that I will sign with you. He said, “If you don’t feel comfortable, stay where you’re at.”
I then went to Suzuki and told them that Honda wanted to sign me and how much they were prepared to give me and that I would have complete control over development of my bikes for 1981. I told them if they didn’t match it I would go sign with Honda right then. Suzuki agreed to the terms and I resigned. For 1981 it read in my contract that I had full control over the development of my bike and as a bonus Suzuki gave me my 1980 twin shock championship bike for winning the championship.
Suzuki teammates Barnett and Howerton make contact trying to occupy the same space at the same time. Werner Strube photo.
- The motor features sand cast center and outer cases held together with steel slot case screws. Everything inside is completely handmade. Nothing will interchange with the production bike. The cylinder and head have massive fining that actually wrap around the front frame down tube. Titanium bolts hold it in the frame. The carburetor is sand cast magnesium that cost in 1980 dollars, $7000.00. The pipe is hydro formed. Riders had their choice of different pipes and cylinders for different power bands. This one is the mid to top end power unit.
- The clutch cable passes through the center case. This is not only very reliable, but helps provide a very light and positive feel. The ignition is a works one that has a very light weight flywheel. Riders had their choice of different ignitions for different powerbands. This one is for mid to top end power. Note how tight the fit is at the transfer port area. The cases are very compact. The chain guide is constructed from very strong hardened steel.
- The rear hub is sand cast magnesium and the brake pivot is titanium. The rear brake torque arm is hand made from aluminum and is very cleverly attached to the rear backing plate via a heim joint through a cast in boss in the backing plate. This provides zero binding. All the wheel spacers and bolts at the rear wheel are titanium. Note the small rubber tubing behind the wingnut. This kept the wingnut from backing off. The factory mechanic touch!!
- An ultra trick carbon fiber chain guide is mounted on the swingarm and attached with titanium bolts. The rear sprocket is also held with titanium. Nearly every bolt on this bike is titanium.
- After the first National at Hangtown Suzuki switched to these Massive front Hubs. They are sand cast magnesium and very light. Braking power was greatly improved. The aluminum ring on the outside is to strengthen the backing plate side. This was needed because of the increased width of the new hub. Without the pressed ring they would surely brake.
- 1980 was the first year for these 43mm Kayaba front forks. Increased rigidity was immediately felt. The sliders are machined aluminum. The inner tubes have improved chrome plating for less stiction.
- A very light weight and well gusseted swingarm supports a set of Ohlins piggyback shocks. These shocks were made just for this bike and provided excellent performance. Flex was about as minimal as could be for a twin shock bike, but not up to par with the soon to be released works Full Floater. At the top shock mount, the frame is strengthened with small diameter chrome moly tubing. The small air box provides large air volume.
- An aluminum brake pedal guard is bolted to the frame. It is swept back in shape to help prevent the brake pedal from getting bent when going through deep ruts. The brake pedal itself is made from very thick aluminum stock. Riders had their choice of many size pedals to choose from. The foot pegs are very strong steel units mounted to titanium brackets that bolt to the frame. The rear brake is cable operated.
- Tiny nylon rollers wrap around a steel fabricated brake cable guide. Details like this never made it to production. The bracket that the side panel mounts to is machined from plexi-glass. After 25 years, Kent's name is still on the seatbase. Riders also had their choice of different height seats.
Mark Barnett and Kent Howerton 1980.