Ok so I adjusted my valve shims over the weekend. Bike starts great now compared to previous hard start. But now the top end sounds like a grenade went off. I posted a video showing my acr assembly with a MASSIVE amount of play in it. My bike is a 2005 and has always been a great runner. Once my bike hecame hard to start cold I found a cracked spark plug and my air filter clogged up earlier than normal. But figured might as well check the valves. The intakes were shut no clearance and the exhaust were out by around .09mm out of spec. Adjusted both and everything looked great. I don't know what happened. I didn't mess with the acr and it was fine before this....... https://youtu.be/D1z2XD8r9bI

See the video anything helps I am assuming I need a new cam

 

I know the ACR is a lose piece and don't remember if that is normal. Rock in a can is often what a lose cam chain sounds like. Check timing again and check that the cam chain tensioner is working and installed properly. The KLX250 is very similar and has had many auto cam chain tensioner failures, but I don't here about this for the 300. Post this in the KLX250 section here as that's where nearly all the action is and those guys will likely have an answer about your KACR.

 

Thanks. It has a keiger manual tensioner..... I need to check that I guess....

 

I watched the video. You can take the cam out and re-stake the compression release shoes carefully with a punch to take out some of the side play. We did that with my KLX650C to take out that excess play. When running, unless the idle is really low, near stalling, the KACR will not normally make noise. If the manual tensioner is still set or was readjusted that should not make the noise.

Here are my thoughts. If you still have the cam cover off:

1. verify you have proper valve clearance - again - you can never verify something too often. Make sure
2. Re stake the compression release rivets to take up the excess side play, but do NOT over do it, they have to be able to pivot out.

If it is buttoned up, listen carefully to the engine while running to determine where the sound is loudest. If it is in the cam cover area it is something with the valves. If you isolate it to the left front corner it is something to do with the compression release. If it is on the right side, readjust te cam chain tensioner per the instructions, starting at step 8. If you don't have the instructions here is a link https://drive.google.com/open?id=1Mq...UHHBBjKZ8MmanM

Do NOT over tighten the tensioner adjuster bolt, you are only taking the play out of the cam chain, not putting tension on the cam chain.

PM me if you have questions, I can give you my phone number if you want to call. I have both a KLX650C and KLX250, the 650 was part of the reason I ended up making tensioner.

 

Ok so meant to update way earlier than now. Tore it all down again. Re adjusted the came chain it jumped two teeth. Adjusted the act and spun engine 1 kick at a time by hand constantly turning the act in until I felt slightest of pressure then stop. About the 4th full engine cycle time the chain was at a constant tension. Fired up first kick. Sounds amazing and runs like a bat outahell compared to how it had been. Took to Gorman ohv park hr from home and ran the **** out of it for two days had a great time absolutely loved my ride