Originally Posted by klx678

Do back off the tension and readjust per the directions. It's all about you getting the best and most out of your KLX, otherwise I'd have just disregarded this post having "made the sale". I actually do care about a rider getting the most out of their ride.

For a clearer understanding for anyone who reads about the tensioner (actually a misnomer, it is an adjuster) I am adding this. The adjuster bolt should not be turned tighter, that's preloading the cam drive. That is not what the instructions direct a rider to do in adjustment. Those directions were worked out through both mechanical design requirements, personal experience, and the experience of others. The instructions for the KLX250 were developed by my own experience with the KLX650 over 30,000+ miles and my other bikes, plus input from TNC, who has some serious time with the 250/300 design engine.

I know it is hard to believe that a bolt that is only finger tight is tight enough, but it is. It's like a small fastener that is torqued to the proper torque value, it may not seem tight enough, but it is. I've run into this a number of times with riders who find it hard to believe finger tight is adequate. That is all the tightness needed to get the cam chain slack out. The locking action of the nut makes the adjuster bolt tight and right with the right adjustment on the cam chain. Remember, the cams are running in plain bearing surfaces machined in the head, so it is best to not have any tension on the drive pulling the cams against the head, but rather to just have the slack out of the chain.

There needs to be a minor bit of slack in a cold engine, which will cause light ticking when cold, for thermal expansion of the engine. When the engine heats up there is little to no chain slack. That is why we recommended a 1/8-1/6 turn looser when cold. It is better to have a tiny bit of slack than to be overtightened. There should not be a preload on the cam drive. After following the directions the engine cam drive will be quiet when warmed up. The fine tuning when hot is for those who really want to be positive, but I'm finding more and more that the cold set is sufficient.



As for the other post wanting to see the differences, here they are:



versus this



The stock tensioner at the top has a problem where the ratchet fails to lock position and suffers damage and wear on the teeth and pawl resulting in failure to maintain adjustment. Not all bikes have the problem, it is a tolerance stacking and wear issue. The wear is not readily apparent, it takes a sharp eye to see the wear (rounding of the rack and pawl) and understanding that the pawl will no longer lock in place.

The simplicity of the manual tensioner is apparent, an adjuster bolt holds the slider shoe in contact with the cam chain to eliminate play, not to hold tension. Perfect adjustment will be zerio play and zero tension. A tiny amount of play is preferable to any tension, 1/8 turn of the adjuster bolt is only .007", so even if it was 1/8 loose it is tiny, but preferable to excess intentional tension.

The complexity of the KLX250 manual tensioner is setting up the right positioning of the adjuster bolt to contact the slider shoe properly. That thru hole required some calculation and rotations in CAD to position it correctly, because not only is the plunger off center and angled, but the plunger tip is cut at a different angle to clear the inside of the head, altering plunger (and thus adjuster bolt) position again.