How To Repair A Chain That Comes Off Chainsaw Guide Bar

A damaged bar or chain may cause the chain to come loose from the bar and can be very dangerous when operating the machine. The bar has a groove around its outer edge, and the chain has teeth that run slightly inside of the bar rails to keep the chain moving straight. To inspect your bar, remove the chain cover, chain and bar. The rails around the perimeter of the bar should be clear of any debris. If the bar is worn down to the point where its rails have become shallow, the bar may need to be replaced altogether. Ensuring your chain oiler is in proper working order at all times can help lengthen the life of your bar. If the chain itself has broken teeth or does not fit back into the rails once it has come off, it will likely need to be replaced. Some chains can be repaired from this type of damage with a flat file. It is important to ensure that the chain fits snugly inside of the bar and that the teeth that keep it from running off of the bar are not worn down too low.

If your chain is tensioned too loose, you risk having it release from the guide bar during operation, which is very dangerous. It is recommended to first get your chain to its proper tension before beginning to use the machine, and then checking every 20 minutes for the first hour of use. The chain should never be allowed to sag from the bar, and should not be able to be pulled more than 1/2 and inch off of the bar at any time. If the tensioner on your saw breaks, you may lose the ability to control the tension of the chain. The tensioner may start moving freely if the screw becomes stripped. To inspect the tensioner, remove the chain cover. Next, remove the tensioner itself and inspect the screw and tension gear. These parts are easy to access, and it will be fairly noticeable if the tensioner is broken. If a new tensioner is required, refer to your user manual for the proper replacement part number.