New member long time lurker. So I recently acquired a 2009 KLX250S with 7005 miles it has a ticking noise. Thought it could be the ACCT though I do not think that is the case. I’ve removed the ACCT brought it a couple of clicks out then reinstalled no change in sound, I then reset and reinstalled it. The previous owner said all he did to it was “Marcelo’s mod” he however had not ridden it in a while and therefore could not remember if it had ticked previously or not.

I have read somewhere that these engines have a “sewing machine sound” to them and that I should not worry about it. The bike also has a bit of a hanging idle from time to time around 3k for a few seconds.
You can view a video of the sound here

 

Seems a little more ticking than normal. I am sure someone with more experience will be here soon.

 

Your cam chain tensioner is failing. As you move in to the right side the noise is louder because that is where the problem is. It may be normal for KLX250s to have this problem, because many do have cam chain tensioner failures, mine did, but left alone it will cause problems First, cam timing is varying as the chain slack varies and second, when there is enough slack it is possible for the cam chain to damage the sliders or even jump a tooth or two destroying the top end and breaking the chain. The solution is to install a manual tensioner, an OEM unit may have the same issue again quickly and they're about twice the price of the manual unit. I know, I had two tensioner failures in my KLX650 in less than 15,000 miles, have had no issue in the 35,000 miles since installing a manual tensioner. It is an easy install taking less than an hour. Adjustment isn't difficult as long as you follow directions and don't overthink things.

I have send a PM and am available for discussion between 8:00am and 9:00pm eastern time. I occasionally miss hearing a call, but will return it when I see it. I'm retired, so no interruption of my work anymore.

If you do a search "cam chain tensioner" in the thread search on the upper right you will find a bunch of threads where it's been mentioned. You will learn most, if not all, have had the problem resolved and no more noise.

 

Similar sounding engine here. I have the Kriega MCCT and will be having it fitted as soon as my replacement clutch arrives also. Hoping for the best 👌