Bought a third CBR (second is a parts bike ) a couple of weeks ago
Non runner when I got it. Got it going now after a carb clean and disassemble.
Valve clearances now. Noticed modded tensioner. Anyone know of this mod and does it need adjustment? Thanks! 😊

 

The centre bit can be lifted up a bit too.

 

I'm not a huge fan of the mod just due to the risk of over-stretching the cam chain. You shouldn't really be able to move it though. It sounds like it's fully slack (ie not tensioning at all)

The previous owner's 'workmanship' looks iffy. If it were me, I'd replace the part. They're cheaper than a new engine, which would be the risk if the chain skipped enough teeth that a piston could hit a valve

Alternately, you can probably get tension by loosening the jam nut, threading the top bolt down, then jamming the nut again. The chain rattle is normal when cold, and it should get quieter when warm. If it's excessively noisy, you can tighten it down some more, but I'd recommend a light touch. Some rattle when warm is totally normal

 

Thanks for your reply. Since balancing the carbs the bike is a lot quieter with the tiniest of rattles- which might be this bolt rattling up and down. Was quite amazing while balancing the carbs too- when they were brought into balance the bike was audibly smoother- could do it by ear rather than the gauge. Didn't happen when I balanced the first CBR or any other bike I've done.

 

My CBR wreck the previous owner told me (and I believe her) that her late husband spent $2k on the engine getting the camchain tensioner and other bits replaced. I have already robbed the alternator chain damper from it so the camchain tensioner is available if this one doesn't work out.