Suzuki's RM250 has one of the most-aggressive stock motors, but I wanted to see if I could change the power characteristics in order to do some fine-tuning. I bolted on a Pro Circuit works pipe and a Factory Sound silencer.
After spinning some laps with the stock jetting, I made a few adjustments as the bike was too lean. I swapped the main jet to a 162 and dropped the clip one, putting it in the third position. The results were huge! The motor gained more midrange. Believe it or not, the powerplant revved a bit slower to the mid and didn't hit as hard, making it much more predictable and tractable. Top-end power still hit hard, but with the PC system it pulled much longer and didn't go flat, instead revving to the moon. Overall throttle response was quicker and cleaner.
The pipe and silencer's craftsmanship is top-notch; all the welds look as if they are off a factory race bike. The pieces mounted easily and required only a few short minutes. The only maintenance the pipe needs is a good scrub after each wash to keep it from rusting, as it is bare metal. The silencer uses a high-quality, super-tight packing. In fact, it is packed so tightly that the bike seems a bit loud at first, but after a few rides, the packing loosens up and the bike quiets a little.
| Pro Circuit: | | 951/738-8050; www.procircuit.com |
| Hard Parts | Max | Rated |
| Installation | 20 | 20 |
| Function | 50 | 49 |
| Durability | 10 | 8 |
| Design | 10 | 10 |
| Price | 10 | 9 |
| Total | 100 | 96 |
If you ride a lot, Pro Circuit recommends you repack the silencer every six months to help keep the sound down. But if it's packed well, the bike sings a beautiful tune as the PC silencer gives the RM a great soundyou know, that factory sound! The works pipe retails for $229.95, and the Factory Sound silencer retails for $119.95.