Inside the 2019 Suzuki RM125 Project

The Truth About the 2019 Suzuki RM125 Project

Three years ago when we were in Kumamoto, Japan, for the All-Japan National MX Championship kickoff to check out the works bikes that are so often a good preview of things to come, we got into a conversation with one of our sources at Suzuki, who fed us some exciting tidbits about the 2019 RM-Z250. He told us that one of the design goals of the bike was to design the new chassis in a manner that would easily accept a two-stroke Suzuki RM engine. Excited about the prospect, we followed up when we got back to the States and dug a little deeper. Indeed, we were told that the idea had been suggested, but that such a plan was not confirmed. In 2017, an RM-Z250/RM125 conversion was on display at the Suzuki booth at the Loretta Lynn’s Amateur National Championships, and in 2018 BarX Motorsports/Chaparral/Suzuki’s Jarrett Frye raced a similar machine at the Freestone Amateur National. The buzz about a potential RM125 conversion kit was certainly alive and well!

When detail photos of the new 2019 Suzuki RM-Z250 were released, it certainly seemed as if the plan had come to fruition as the dual-cradle design of the frame met the downtube much higher than the previous machine, offering room for a two-stroke exhaust to exit between the frame rails. Suzuki flew the press to Japan to ride the new machine at Meihan Sports Land in late 2018, but when we asked about the rumored two-stroke conversion kit, all we got were blank stares and denials. Sad, we figured that it was all too good to be true anyway, and kind of forgot about it.

A few weeks ago, however, our interest was piqued when we got a call from Suzuki Motor of America’s Off-Road Technician Kevin Macahilig, who asked if we wanted to race the upcoming Wiseco Pistons Two-Stroke World Championships presented by Fasthouse, aboard a RM125 that he had at the shop. We had already planned on fielding a couple of our 2019 250s from Yamaha and KTM, and politely declined. Then he sent us the photo at the top of this post, and we were literally on our way to Suzuki’s headquarters in Brea within minutes.

Maybe it’s because it’s a machine we’ve all been longing for, but the bike looked absolutely badass. The bodywork and color scheme that Suzuki debuted in 2018 on the RM-Z450 is awesome anyway, but with a tiny two-stroke engine tucked inside of it, it looked even better. The bike is indeed a 2019 RM-Z250 chassis, but upon closer inspection, it did require modification to the left side lower engine mount.

Aside from some minor modifications to the lower engine mounts, which appeared to have been relocated slightly, all that was needed were a set of handmade top engine mounts, a carburetor air boot from an RM125, some tweaks to the exhaust pipe and silencer, and a custom plate and fuel petcock for the bottom of the RM-Z250’s aluminum fuel tank, as the stock fuel pump must be removed.

The standard 2019 RM-Z250 comes radically oversprung for anyone who is not intending to race Supercross, so a set of softer springs, front and rear, were installed to both bring the bike back to reality and to compensate for the RM125 engine’s much lighter weight. (With a half-tank of fuel, we weighed the bike at 214 pounds on the @dirt.bike.tv scale.) All in all, except for the top engine mounts, the bike looked very much like it could have been a production machine. On our way home from picking it up at Suzuki, we stopped at a grocery store for some food. When we came out, there were a couple of guys checking it out, as it caught their eyes immediately. Obviously, there is an excitement and desire for two-stroke dirt bikes!

The bike’s engine was bone-stock, but we knew that some added performance could easily be coaxed out of it by our friends at Bill’s Pipes, the legendary exhaust company that really enjoyed some big successes in motocross racing with guys like Steve Lamson, Doug Henry, Buddy Antunez, Travis Pastrana, Damon Bradshaw, and more. 

We dropped the bike off at Bill’s Pipes in Corona, California, before we even took it to the track for a test run and they made one of their wildly popular Cone-Look pipes fit with some minor bracket relocation. Though motor man Jeff Springman was anxious to get inside the top end and grind away in search of better power, we declined as we did not want to perform modifications that were not approved by Suzuki.

Our first day at the track was a wild one. We headed to Milestone MX Park in Riverside, CA, to spin our first laps on both the RM125 and brush up on our two-stroke skills aboard our 2019 KTM 250 SX. Our buddy Alex Ray of the HEP Suzuki squad was also there to spin some laps on his RM-Z450, and we couldn’t say no when he asked to try out the exciting new tiddler.

It had been years since ARay had ridden a 125, but he looked right at home on the machine in short order and the sound of the small-bore two-stroke on the track turned heads in the pits. We slapped our GoPro Hero7 Black on the top of his 6D Helmet and grabbed some sweet footage that chalked up a ton of views on our Swapmoto Live YouTube Channel. (Click link and subscribe!)

 

Truth be told, the bike had a pretty gnarly bog when you’d land hard off jumps, but it was a chilly day and we assumed it was the cold weather that was causing it. “Just pull in the clutch a little bit before you land,” said Ray. “That way if it bogs you won’t go over the bars!” When we picked up the bike, Macahilig also gave up two boxes filled with parts. Inside them were spare carburetors, flywheel weights, air filters, a Ratio Rite, three bottles of Maxima K2 premix, and a bag full of different shift levers. The stock RM125 shift lever was a little short for our size 9 boots, so we swapped it out for a longer one and it was perfect. A turn in on the fuel screw helped the bog. All in all, the RM125 was an absolute blast to ride. It wasn’t the fastest thing we’d ever ridden, but it handled amazingly well and we couldn’t wait to race it! Check out this Chase Curtis video of A-Ray in action during our first day on the bike.

With only a week before the race, we knew that we had to scramble to get numberplate backgrounds made for the bike. Of course, we forgot to order them for a few days and by the time we remembered there were only three days left. Pistonbones Printing is a graphics and custom printing company that’s located right down the street from us in Corona, and owners Jessica and Brian Pappalardo are long-time friends of ours. They responded well to our last-minute request and within a day we got a design for approval. 

The following day, we picked up our finished graphics kit, swiped the numberplates off of our 2019 RM-Z250 test bike to use as spares for A-Ray’s numbers, and finished up our one-day race bike. The kit went on easily, fit perfectly, and stayed affixed with no bubbling or lasagna ripples on the edges the next day. Boyesen Engineering sent us a clutch and ignition cover to complete the look of the bike and better protect against rocks and roost, and we were set to go racing! 

Race day turned out perfect. The weather remained overcast for much of the day, so the track conditions remained great for most of the day. Of course, with a stock motor the bike was far from blazingly fast up the big hills, but the traditional Suzuki handling of the RM-Z250 chassis, coupled with the light weight of the RM powerplant, allowed the RM125 to handle amazingly well. The bike was a missile on the rough Glen Helen downhills and it carved through the rutted and sandy sections of the track with precision.

While my motos were super fun and fairly uneventful – get a bad start, catch up, finish with a smile – the fire drill that ensued the second I returned to the pits was comical. I was in race six, and A-Ray was in moto eight. That meant that as I returned to the pits, his race was being called to the starting line. As soon as I pulled up and put the bike on the stand, we needed to swap all three numberplates (uh, Suzuki? Why two bolts holding the front numberplate on?), fill the gas tank, and lube the chain. It doesn’t sound like much, but in a time constraint, such tasks are a handful! I can’t imagine how gnarly it is when the mechanics at a pro race need to swap out a blown engine in between motos!

In the 125 Pro class, A-Ray ultimately finished fourth overall aboard the RM125, an impressive feat considering he was on a stock engine with a pipe. It was almost comical in the first moto watching Rockstar Energy Husqvarna Off-Road Racing Team Manager Timmy Weigand pull Ray up the big hills of Glen Helen on a factory TC 112 Supermini! Ultimately, Alex turned in 7-4 moto scores in a field of 24 aboard our special Suzuki RM125 and is probably still smiling about all the fun he had.

So, will we ever see the “Two-Stroke Conversion Kit” ever offered for sale by Suzuki Motor of America? It’s highly unlikely, according to an internal source. If anything, an aftermarket company could easily develop a kit consisting of parts similar to those found on the bike we raced. But, you never know…the attention that this bike stirred up on social media was significant, and Suzuki Japan is certainly watching. The jigs to put the old RM steel chassis back into production are no longer in existence, but there are plenty of engine parts still around…

One can hope!

Thanks to Aki Goto, Kevin Macahilig, and Chris Wheeler for the opportunity to spend some time on this truly unique machine. We enjoyed every minute of it!