WE TEST THE 2006 SUZUKI RM125 TWO-STROKE

The 2006 Suzuki RM125 in action. This article is from an archived issue of MXA. 

This just might be the last year of the 125cc two-stroke (at least in terms of the little two-strokes receiving any mods beyond BNG). How can we say such a thing? That’s simple! Kawasaki decided not to bring the 2006 KX125 to the United States, and Honda made only one change to the CR125 for 2006 the radiator sticker (and to be honest, you can barely tell they did that). Yet, amid all the doom-and-gloom for tiddlers, there are a few bright spots and Suzuki’s RM125 is one of them.

So how did Suzuki separate themselves from the dying herd? They made improvements to the RM125. Which, shockingly, is something that they were unable to do to the better-selling RM-Z250. We like to think that Suzuki’s engineers knew they could make the RM125 better, and rather than take the easy and cheap way out, they did right by their customers. They set aside R&D time and seed money to make the 2006 RM125 better than the 2005 model. Kudos.

Q: WHAT EXACTLY DID SUZUKI CHANGE ON THE 2006 RM125?

A: They fine tuned it. They increased the diameter of the piston ring knock pin, made the reed valve intake passage narrower, reshaped the exhaust chamber, created a new CDI ignition map and put Renthal Fatbars on it.

Q: WHAT DO THESE MODS MEAN ON THE TRACK?

A: Unfortunately, not a whole lot. The engine is still a mid-and-up maven. Don’t waste your time trying to lug it down low. It doesn’t pull hard down low like a 250cc four-stroke, or YZ125, or even the MIA KX125. To make the most of the RM125’s power profile, the best strategy is to fan the clutch on the exit of every corner. Oh yeah, make sure the throttle is wide open. You have to keep the RM up in the rev range. If you can do this, the engine is competitive and will work with you. Fall off the pipe and you start from scratch.

To make the most of the RM125’s power profile, the best strategy is to fan the clutch on the exit of every corner.

Q: IS THE 2006 RM125 FASTER THAN THE 2005 MODEL?

A: Yes. Is it a lot faster? No. If you were expecting the RM125 to magically become a weapon of mass destruction against 250 four-strokes, you will be sorely disappointed. The 2006 RM125 is a great entry-level machine for young riders making the jump up from the mini ranks, or for someone in the market for a fun bike that will be cheap to maintain.

Q: HOW GOOD IS THE SHOWA SUSPENSION?

A: Much improved. Over the last few model years, the MXA wrecking crew has complained about how soft the RM125 suspension was. Suzuki listened. The 2006 RM125 features much more realistic suspension for the average motocross racer. Finally, it has some versatility for a wide range of riders not just mini refugees. It can still be set up on the soft side for lightweights (by taking most of the compression out in both the forks and shock), but it comes from the factory set up stiff enough to handle normal-size riders. How did Suzuki accomplish this feat? They stiffened up the valving on the forks and actually went to a stiffer spring rate on the shock.

Forks: If it were us, we’d opt for the stiffer 0.43kg/mm front fork springs. This is a necessary mod for most Intermediate and Pro racers, as well as heavier riders. The stiffer springs make the forks ride up higher in their stroke and just give the bike an overall better feel. To complement the stiffer fork springs, we chose to set the compression and rebound clickers at ten out.

Shock: On the shock, we set the sag at 98mm and turned the compression to 12 out with the rebound set at ten out. We opted for the stiffer 0.43kg/mm front fork springs. 

Q: HOW DOES THE RM125 HANDLE?

A: Cornering has always been a Suzuki strong point, but high-speed stability has been its weak link. As it sits, the 2006 RM125 is a cornering fool. It loves to dive inside. Its second best trait is air time. This bike lives to jump. It feels well balanced in the air. It’s a little busy at speed, but because the bike feels light, the suspension is stiffer and the balance is better, it’s not scary.

Q: WHAT DID WE HATE?

A:The hate list:

(1) Power: It’s good for a 125, but not as good as the YZ125 or KTM 125SX. If we were to throw all the 250Fs in the mix, that leaves the RM125 eighth on the list.

Q:WHAT DID WE LIKE?

A:The like list:

(1) Handlebars: Last year Suzuki had cheap knockoff aluminum handlebars. This year they got official oversized Renthal Fatbars. That’s one heck of an improvement.
(2) Power: We know it was on the hate list, but we like the way the RM125 engine runs. It’s exciting. Hold this bad boy wide open, fan the clutch and listen to the engine sing. You’ll be living on the edge, but sometimes that’s the only thing that makes life worthwhile.
(3) Controls. It just feels like all the controls on the RM125 are in the right place. The clutch perch is perfect, it stops on a dime, and it shifts with ease.

Q:WHAT DO WE REALLY THINK?

A: It’s hard not to like the RM125. Unfortunately, we all must come to the realization that it’s not really competitive in the 125 class against 250 four-strokes any more (and even if it was, it’s not the best 125 two-stroke choice either). But it is a vastly improved 125 that deserves to spend time racing around a motocross track.