Reply To: GV 125 S Valve clearance
I would say i prefer that noise than an eerie too quiet of a motor, as that silence kills so to speak but if the rattling sounds increase with revs in tandem , it suggests:
– one of the shims is too thin (clearances too wide between the cam lobe and bucket)
As the lobe presses down, and lets go ==> if the gap is too much, the bucket’s valve spring shoots it back up until meets the lobe again (almost like instantenous metalic fist bumping, if i can even describe that correctly!)
Cam Tensioner (as the hottest cylinder than the front) , this could be likely as the chain races up and down , the tensioner’s ratchet may be juddering or causing a chain rattle slightly but , you did not mention if the tensioners have changed their sounds from either front or rear or if they both sound identical ? So i will leave that for you to judge with a screwdriver on it and other side of the screwdriver on your ear.
– debris along the cam bucket and inside the shim itself, affecting final clearance figures or that the engine needs to be spun by hand a few more times ice cold to verify clearances before starting it.
Hope this helps!