DRZ125 Engine knocks

[mackmanj]

My son recently purchased a 2007 Suzuki DRZ125 that smoked and had a knock in the engine. We tore it down and found a small piece of metal in the combustion chamber. I did a jug up overhaul with new piston kit and gaskets. When we got it running it still has the knock. It sounds like it is coming from the whole engine and is hard to narrow down and does vary with engine speed. I checked the rod for excessive play and it seemed to be ok. I have changed the oil 3 times to see if any trash comes out with it and it is good. He rode it the other day and a piece of the intake valve guide broke off and stuck the intake valve open. Ive had the top jug off 3 times and cant find anything. Does anybody have any ideas on what I need to look for. I hate to split the bottom end but I will if I need to. I am going to tear down this weekend to repair the head and hope to find it this time before I wear the bolt holes out. I have done several single cyl Hondas in my day and didnt think this Suzuki would be any harder than they are. Thanks in advance for any advice.

 

[pesky nz]

This motor has a manual cam chain adjuster and to get the best out of them you need to let the 2 mounting bolts off about 3 mm then adjust the chain by releasing the lock nut and screw then re-tighten the screw and lock nut. Now let the mouting bolts off completely and remove the whole tensioner clean gasket area and refit the tensioner. The reason for the complication is that there are 2 springs inside the tensioner and the wrong one is strongest. Less work than splitting the cases so worth a try first

 

[mackmanj]

Thanks Pesky for the advice. I'm going to work on it this weekend and I'll post what I find.

 

[Matt90GT]

well you know you need to redo the head already. new valve guides and seats.

check the cam chain, otherwise it is a crank and main bearings.