Chain Tensioner

As a swingarm type rear suspension goes through its travel, the distance between the axle and countershaft sprocket changes as a function of the wheel travel - so it stands to reason that our machine's improved, more expanded wheel travel will likely cause us grief. The fact of the matter is that the stock machine was never really intended to move its rear wheel as much as a competition or even an aggressively ridden mini quad. Whether your young pilot is a spirited trail rider or a full fledged racer, throwing a chain can be extremely frustrating, and even dangerous.

The HPD chain tension has features designed to last.

To combat the continual changing chain length requirement that occurs during wheel travel, an OEM will attempt to locate the countershaft sprocket as close to the swingarm pivot as possible; ideally, they'd be one and the same. But of course, this is not practically possible and usually not required. But the longer the travel or bumpier the ride, the worse the situation. The solution to the problem is an aftermarket chain tensioner.

Some manufactures have begun to offer a chain tensioner on their machines right from the showroom floor, but none are as robust and effective as the one that comes from HPD Inc. Their unit, which is designed for the Polaris Predator, Scrambler/Sportsman, Alphasports, and Xtreme youth ATVs, features a heavy duty nylon roller with sealed bearing, a billet CNC machined arm, and zinc dichromate plated mount. The unit is designed to minimize the slack in the chain by holding it up against the sprockets, which maximizes the wrap around the sprockets and eliminates the tendency for the chain to derail.

The unit as installed on a Predator 90..

To install the unit, the chain guard must be removed (less weight!). But make sure to adjust the chain first before beginning the installation of the tensioner. With the axle, swingarm pivot, and countershaft sprocket in line adjust the chain for minimal slack, but not taught. This point will be the tightest through the suspension travel; everywhere else the chain will be more slack.  Our experience with this unit indicates the easiest way to install it is to remove the screw that holds the nylon wheel to the tensioner arm then attach the bracket and arm to the swingarm with the torsion spring already hooked up. Then once firmly fastened, use a pair of channel locks or large adjustable wrench to retract the tensioner arm (counter-clockwise in the photo above) and then install the roller and attachment screw with the arm pulled down out of the way.

In our particular case, with a machine that was throwing chains left and right, the HPD unit fixed the problem for good, with not a single issue since.

Steering Stabilizer

If your machine is particularly darty, jumping side to side when going through the rough stuff, a steering stabilizer can be a real aid in keeping things in check. The basic idea is to dampen the rotational motion of the steering stem by installing a "shock absorber" of sorts between the steering stem and a fixed point on the chassis. At slower steering input speeds the stabilizer's effect is neglible, however, it really takes the jolt out of a sudden side wheel impact when the steering is suddenly forced to quickly move. Also, it helps to eliminate some of the twitchiness that these relatively simplistic suspensions seem to exhibit, especially when equipped with wheel spacers (due to the increased scrub radius at the front wheels). 

The stabilizer is installed by connecting the rod end of the damper to the steering stem via a two-piece clamp, then attaching the body end of the damper to a convenient location on the frame of the quad. This can be the most challenging aspect of the installation since many of the aftermarket dampers were originally designed for full sized machines and are a bit on the large side. Unless specifically offered, it is sometimes required to fabricate your own brackets or mounts. Hetrick Racing offers a billet frame mount for the Gibson unit that allows for "drop in" installation for some of the more common mini quads brands. Once installed, the Gibson unit becomes 8-way adjustable for a variety of riding/racing conditions and rider tastes. The adjustments essential affect how quickly or slowly the stabilizer reacts to steering inputs, both from the rider and terrain.