Having a problem blowing belts? You are not alone and we are here to help. Blowing belts can happen for many reasons and you need to cover the bases to prevent it from happening again. Below we outline a few reasons why belts blow, and how to check for them.
Belt Quality & Break-In: make sure you are using an OEM or a belt proven to be as good or better than OEM. Belt material and the ability to stand up to high temps without deteriorating is a big deal. This is why we recommend the G-Boost belts or OEM from all of our testing. When you get a new belt, make sure to clean it with soap and warm water to wash away oils from manufacturing. After installation, put some heat into the belt slowly by running at 20-30mph in your low gear for around 10 minutes and let it completely cool. If possible, do this 2-3 times. Keep in mind different belts can change your peak RPM depending on the compound they are made from, so you might need to adjust clutching for a different brand belt.
Clutch Cleanliness: Make sure to always use an abrasive Scotch-Brite pad and scuff up your clutch sheaves where the belt rides. This will give the best bite on the belt and reduce clutch slipping. Blow your clutches out with compressed air often. These are moving parts and keeping them clean will not only help them move freely, but it will greatly extend your clutch life.
Clutch Wear: Check for abnormal grooves or pits in the clutch sheaves (where the belt rides). The primary clutch can get a large groove in it near the bottom where engagement happens. This can be from belt slip right out of the gate, a loose belt, power braking…. etc. A small groove or ring is okay, but if it gets too deep this can wear a belt out fast. Check all moving parts to make sure rollers spin, weights move, no flat spots on rollers… etc. One of the best ways to actuate a clutch is to pull the springs out of it and move it back and forth. If you feel something binding you know there is a problem. Make sure to check all wearable items in your particular clutch. Normally if something is wrong, it’s obvious.
Clutch Setup: This is another huge problem! We deliver you clutch kits and setups that tell you your peak RPM normally around 55 MPH wide open throttle. This is best done from a 10-20 MPH roll-on. You want your target RPM to match what we list on your setup guideline. This will basically set how your clutch works at all RPM and speeds to be best for performance and belt life. If you have another clutch kit and it didn’t include this important information, you need to think about a new clutch kit. Too high of RPM will not grab the belt tight enough resulting in slippage, and too low of RPM will over shift the clutch and cause belt slippage also. Many other factors play into this, but make sure your clutch is grabbing the belt tight and has the correct components for the modifications and tire size you run.
Clutch alignment: If your clutches are not perfectly in line this will cause the belt to hit more on one side than the other. This creates heat and can cause all sorts of belt issues. Don’t want to purchase an expensive alignment tool? Use your cell phone camera to get a good idea of your alignment (see picture below). If you are blowing belts because of clutch alignment, this method normally works well enough to let you know you have an issue. To fix belt alignment issues you will either have to loosen motor & transmission mounts or shim behind the clutch. This all varies depending on model, so please refer to a service manual for the proper procedure. Sometimes we have had a misaligned clutch that simply needs to be pulled off, clean the taper on the clutch and crank, then torqued back down. Below you will see what angle to take a picture from and that these clutches are not properly aligned. The belt should sit straight in the clutch.
Belt Deflection (Tension): If your belt is too tight or too loose it can cause many issues. Free play on the belt really depends on the machine and clutches they use. Normally we want the belt as tight as possible without spinning the secondary clutch in park. A slight spin is okay, but a constant and fast spinning clutch is not okay. A belt that is far too loose will have the worst effect on belt life as it will always be fighting to gain tension, and normally slip at lower speeds. This will put flat spots in the belt and prematurely wear it out. Adjusting the belt deflection depends on your model. The RZR XP Turbo clutches can purchase our snap ring delete/deflection kit to adjust deflection. Many of the smaller diameter naturally aspirated clutches will need to be split and shims added to adjust this.
Clutch Cover Vents: Make sure to keep them clean! After blowing a belt, many times we will find debris in the clutch ducts that can clog them. This causes heat buildup and another blown belt.
Heat: The killer of all belts is heat in some way or another. If any of the above things are not correct they will cause excessive heat and contribute to a blown belt. Even if everything is correct, you can still see heat being a problem… especially with larger tires, heavier machines, and machines with greater power. These machines demand a lot from the belt. Some fans out there will help, but many actually restrict airflow in higher RPM where the clutches are working to pump air through the cover. Proper clutch breathing is important. Always run your clutch cover and find ways to add other ducts to the clutch cover if possible. We run them, highly recommend them, and sell the Razorback infrared belt temp gauges to monitor temps.
Improper Clutch Use: Power Braking (clutch/gas at the same time), high gear to climb technical sections, mud & water getting into the clutch cover, and excessive time spent at high speeds can all cause issues. If you beat the clutches and belt, they are the weak link. As wearable items, they are designed to fail first, and sometimes that’s simply the fault of the right foot.
-Mike @ Aftermarket Assassins