Season Prep

SEASON PREP by Kyle Roggenkamp

‘Primary’ pre-season focus:

Clutching is the difference maker. Not just in winning races on the track, but in overall performance of trail sleds as well. And just like the wrong clutching setup will sink a racer’s day, poor clutch maintenance will sink a trail rider’s day. There’s nothing more frustrating than worn out clutches ruining an otherwise perfect day of riding or racing. Clutch technology has come a long way in recent years, and reliability is certainly better than it’s ever been. But there are still wearitems that, left un-checked, will cause headaches and ruin your ride (or season!).

Practice tracks are now open, and trails will be open shortly, so I am working feverishly in the shop preparing race sleds for the track and trail sleds for the trail. My trail sled preparation starts the same way my race sled preparation begins – it starts with the primary clutch. The primary clutch is attached directly to the crankshaft of the engine, and it takes a beating, even if the sled isn’t ridden excessively hard. It’s constantly shifting as RPM is changing, and all that movement is wearing out parts!

Fortunately these parts are not expensive, and with a few simple (but admittedly specialized) hand tools and a couple of hours each pre-season, any sled can be dialed in to provide an outstanding season of trouble-free riding. A primary clutch has several wear-items in its design, but for simplicity, I zoom in on 3 things that do not require special tools to remove the spider from the clutch.

Over time, primary springs take a set, the rates change, and they will inevitably fail like this one. But they’re cheap and easy to replace. Swapping a primary spring out every year is a cheap insurance policy to avoid a failure and keep that sled running like it should! Simply pull the clutch off the engine with a clutch puller, which you can get from dealers or online retailers like Dennis Kirk. Remove the cover bolts to gain access to the spring. I use a clutch compression tool like this one to make the job easier, but in a pinch, a buddy pushing down on the cover while removing the bolts will also get the job done. A broken spring like this will drop engagement RPM to something close to idle, and it won’t be able to get anywhere close to the correct peak RPM. $30-40 each pre-season will prevent this issue from surfacing on the trail – money well-spent in my book!

Weight bushings are the second wear item I check on each season. Again, they are cheap parts that wear out over time. When they are worn to the point they require replacement, they will allow the weight to rock side-to-side, which will bind up the clutch, and ruin the performance of any sled.

Aftermarket shops like Speedwerx sell these for most makes and models and they are easily replaced with a simple tool like this bushing press tool – which are available from companies like EPI.

The last simple maintenance item I look to is cover bushings. These typically start showing wear at higher-mileage marks. As they wear, they allow the cover to rock back and forth

which will again, cause the primary clutch to bind when it is trying to shift. This 2000 XC 600 SP is my 12 year-old’s trail sled, and is approaching the 7,000 mile mark. It has lived a rough life so far, and is begging for a new cover bushing. The bushings are cheap and are readily available. It takes a simple pick to remove a retaining ring on the backside of the cover, and a spacer to push the bushing out of the cover and push the new one back in. I use a specialized press tool from EPI, but a socket of the correct diameter will also get the job done.

While every manufacturer has different designs, the fundamentals are the same, and the areas that wear out and will take performance away from your sled are the same. Getting that primary clutch tuned up doesn’t take much time or money, but can make a huge difference on the track or trail. So if you take an evening this preseason to dial-in that primary clutch, you’ll be one step closer to a sled that flat-out rips all season long!