Yamaha gladiator chain sprocket damaged within 6 months why

The chain tensioner is possibly bad. Here's a youtube on the subject:

https://www.youtube.com/watch?v=6NKuOM9pQNk

14 - 41 = 2.93 ratio
15 - 46 = 3.06 ratio..
6-7 links.. you need to move the axle all the way forward when installing a new chain... (it will stretch!) moving the axle all the way forward gives you plenty of adjustment later!!

Increase in idle is usually a vacuum leak in the intake or carburetor. The poor acceleration can be a stretched timing chain that jumped a tooth on the cam sprocket or the slide in the carburetor isn't raising as it should due to bad diaphragm at the top of the piston if yours has one. Easiest way to check the carb is to remove the intake boot on the carb and watch the slide in the carb when you rev the engine. If it isn't rising up quickly when you pull full throttle then you have either an air leak in front of the carb or the slide is sticking/diaphragm is bad. There is a TDC mark on the flywheel on the left side of the engine usually found by removing a small plug or a round cover over the flywheel. TDC mark aligns with notch or pointer then remove cover on the head on left side to check the timing chain sprocket . There is a mark on the head that aligns with a mark on the sprocket at TDC (top dead center). If the timing mark is off to the right on the sprocket the chain has jumped time. You have to remove the timing chain tensioner on the back of the cylinder (two screws) then you will have enough slack to jump the chain back on the sprocket . Then replace the tensioner , release the tensioner by loosening the lock nut on top of the shaft or lock screw then retighten it. Do not overtighten or you will damage the slide inside that applies pressure to the chain. Recheck your timing marks. Sometimes the exhaust valve is bent when the chain jumps. You can check compression with a gauge or by putting your finger over the spark plug hole tightly and turning the engine over with the starter with the spark plug grounded . You must ground the spark plug or it can fry the ignition system. Good luck!

Does the sprocket drive shaft turn when the sprocket does not? If so, look for broken coupling between the shaft and the sprocket. If the output shaft doesn't turn, then suspect a damaged (probably plastic) gear within the gearbox. Hope this helps!

I hate to give you the bad news but it is not likely the damaged sprocket is under warranty. The sprocket was not bent when it left the showroom floor and Yamaha Corporation has no control where and how you drive.

Chains should run true and not be forced to move side to side to fit a bent sprocket. The sprockets are hardened steel. It is not a good idea to bend them back and forth.

You didn't say which sprocket had the problem. A front sprocket will cost around $30 and a rear sprocket will cost around $60. Installation will also cost unless you do it yourself.

Please rate this solution. Thanks!

not sure i know rk used to make a gold chain that was very good, stay away from ek