Installing go-fast parts

By the staff of Dirt Wheels


Virtually any component of your favorite ATV can be exchanged for a part that was designed to improve your riding experience. Yamaha spent countless hours making sure that adding a 1 1/8-inch fat bar to their YFZ450R would improve its overall handling and ride quality, and it certainly did.

However, the aftermarket innovates and adds products to our world of off-roading that can considerably improve the handling of our favorite machines.

One such product is the Fasst Company Flexx handlebar. It offers what we consider an extra bit of suspension that further smooths out the already plush ride of the Yamaha. The Flexx bar has a hinge system with elastomers that soak up hard hits and rough chop, all while cutting down on vibration.

You can get the bar for almost any ATV with a 1 1/8-inch-size bar clamp, or you can upgrade your 7/8-inch clamps to the correct size to fit the Flexx bar or any other handlebar you choose. In this “How-To,” we are showing you how easy it can be to change out a handlebar on a 2019 Yamaha YFZ450R, and the knowledge can be transferred over to many other ATV brands and models!


The best way to start this process is to figure out what tools you will need. After looking everything over, we gathered up a #2 Phillips screwdriver (the one in your stock toolkit will fit best on the Japanese screws), a ratchet wrench with an extension, 8mm and 12mm sockets, 12mm combo wrench, and, in our case, Allen wrenches for our lock-on ODI grips and Pro Design ATV kill switch.

You can change your Yamaha handlebar to a bar from many different manufacturers for a different height and sweep for your riding comfort and control. We wanted the extra smoothness the Fasst Co. bar provides. You will need the proper tools to adjust the bolt the elastomers ride on. You will also need new grips to install on your new handlebar. We utilized the ODI lock-on grips that we were already using on the Yamaha.


Begin removing any items that get in the way of mounting hardware and wiring attached to the stock handlebar. You maybe be able to reuse the components like the zip-ties, so do not discard them until the job is done. On the Yamaha, a plastic cover needs to be removed and two zip-ties.

We started on the clutch side. Most perch mounting bolts will have 8mm or Phillips heads. We removed the clutch perch first.

It is a great idea to reinstall the mounting hardware loosely to the part you just removed so all components are in the correct direction to reinstall. This aids in not losing parts as you perform your tasks.


Most handlebar-mounted switch blocks utilize Phillips head screws in the plastic to mount to the bar. Remove both screws on the Yamaha’s block, spread it, and remove it from the bar. It is a good idea to either use compressed air to blow the dirt out of the inside of the block or grab a can of contact cleaner and spray the inside. The cleaner will dry up quickly. It is also beneficial to put some dielectric grease around any electrical contact points inside the block to resist corrosion later.

Now that the clutch side is done, we began by removing the YFZ450R’s thumb throttle, which required the removal of two Phillips-head screws. If you run into a screw that will not come loose, place the screwdriver firmly in the screw head and lightly tap the bottom of the screwdriver handle with a dead-blow hammer.

This shocks the wedged threads into a slightly different position. That can release their hold on each other and allow the screw to come loose. You could also utilize an impact driver that can be purchased at your local auto parts store or tool store.

The brake perch was the next piece of the puzzle to be removed. Take note that the perch clamp may have a direction that tells you which side should go up when reinstalling later.



We lightly drape the components over the hood of our machine while changing out the handlebar. This keeps the parts properly separated for reinstallation. It is a great idea to replace your throttle and clutch cable at this time, or clean and lubricate them.

If your machine is older, we suggest changing the cables, but if it’s only a few years old, lubrication and cleaning are in order. If you do lubricate the cables with the proper type of cable lube, then you will have to do this again after every cleaning due to dirt and debris sticking to the lubrication inside the cable.

More than likely you won’t need to remove the handlebar clamps from the steering stem unless your older ATV requires bigger clamps for handlebars like the Flexx bar or other fat bars. We removed mounting bolts from the bar clamps so the bar could be taken off the quad.

Mounting clamps tend to be shorter on one side than the other. This allows the clamp to “pinch” the handlebar in the brackets tightly without using a large amount of torque on the bolts. Generally, the side facing the front of the machine will be longer, and it needs to be tightened securely first. (Note: Purchasing a mechanic’s manual for your machine will tell you all the torque values needed to tighten all components).

On the top side of the clamp, either there will be an indentation signaling which side should be placed forward, or you can mark the clamps before you remove them.


Place the new bar in the clamps and begin by placing all four screws and clamps in the proper location. Always hand-thread screws a few turns before utilizing a tool on them. This ensures you don’t ruin the threads. Tighten the top mounting bolts enough to where you can still move the new handlebar forward and back in the clamps easily, but it stays in position easily.


Handlebars generally have adjustment markings on them, and bar clamps may have arrows or points that help you line up the bar in a central location and tilted to where it’s most comfortable for you. We usually take note of where the stock bar was lined up prior to removal so we can easily put the new bar in a similar location. Once the bar is where you want it, you can fully secure the top bolts, and then tighten down the rear ones to spec.

After loosely reinstalling the throttle, clutch/brake perches, and switch block, we fit on the grips. If you have lock-on grips, it’s easy to slide them on, set your controls properly and tighten everything down. If you have to glue your grips on, it is best to perform that task prior to remounting all of the components.


At this point, set all of your controls where you want them. Make sure you tighten the top bolts of your perches before the bottom ones. They also tend to work like handlebar clamps and pinch the perch onto the handlebar. We put a small amount of grease on the end of the bolt’s threads upon installation. Perches are generally made from aluminum, while the bolts are steel. These two metals in contact will corrode over time. The grease prevents that.

Now your task should almost be complete! Reattach the wires with the zip-ties (if required) to the handlebar. Check that all controls and mounting bolts and screws are tightened properly. Cables should be able to move freely.

We suggest going for a ride and feeling out the controls. Readjust where you want them to be. Handlebars with different heights, sweeps, or functions may encourage you to set your lever or throttle heights differently. 

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