- Bike Checks
You can have the latest titanium parts, motor work, and race gas for your scoot, but if your clutch isn’t working properly, all of those goodies are for naught. When your clutch plates are not fully engaging, your engine can pump out all of the power it wants, but a lot of that will be lost by the time the energy gets to the rear wheel.
In motocross, torque is key, so a slipping clutch can mean the difference between winning a moto, and not even landing on the podium (or finishing the race for that matter).
As the saying goes, stock is best. In fact, you would probably be surprised at the amount of stock components many professional racing teams use. However, one exception to the rule is clutches. Take a peak at the bikes under just about every factory team tent, and you’ll notice the name Hinson etched into the clutch covers of the best bikes in the world.
Hinson has amassed an astounding number of championships since coming onto the market back in 1992, and enough street cred that they are the go-to source for clutch components.
For this reason, it was a no-brainer on who to call when it came time to replace the clutch on our tired 2005 YZ125. After installing some fresh clutch plates with almost no improvement in performance, the writing was on the wall that the clutch basket was in need of an upgrade.
Upon removing the stock components (unless you have the tool to hold the hub and basket, an impact driver should do the trick to remove the main nut), we noticed the indicative notching on both the inner hub teeth (caused by the steel plates) and the basket teeth (caused by the friction plates). The notches are basically divots that prevent the plates from sliding smoothing. They can even cause the plates to catch on the hub or basket, preventing the clutch from properly disengaging.
The good thing about Hinson components is that, although they have some of their own unique design features, they can also be mated to OEM parts. Although we went with the complete rebuilt kit, it’s a good thing to know.
The CNC machined billet aluminum parts are a sight to behold and it’s almost a shame that they are not visible once installed, except for the clutch cover, of course.
One aspect of the kit that is different from stock for the YZ125 is on the Billet Proof inner hub. Every third slot on the hub has three holes drilled into it. These holes allow for additional oil flow amongst the steel and fiber clutch plates, forcing oil through the plates from the inside out with centrifugal force; a small but very functional innovation. More oil flow means a better functioning clutch.
With everything bolted back up, the difference on the track is night and day from the worn out stock unit. On a 125, you need every ounce of power you can get, especially when you weigh about 40 pounds more than the target rider weight. Exiting corners and hammering down straights once again elicits the snappy, responsive feel that the little YZ’s are known for.
Are Hinson clutch kits cheap? No, but they are less than many four-stroke exhaust systems, and the advantages are clear for the get go. We have not yet had the Hinson system installed for long enough to give any durability feedback, but considering the company’s racing credentials, we’re not expecting any major complaints.
For more information on Hinson Clutch Components, visit www.hinsonracing.com.