Firstly, Hello everyone! I'm new here (new to MX and also to this forum) so just a quick greeting from England, London (Kent)! Ok, so i've taken on what some would consider a handful for my first project bike... an 1990 YZ250 (1989 Engine) Im part way stripping down my bike and i've come across (what could be) my first problem, a chipped power valve? See pictures below. now.. i assume this is some kind of stone chip and is not a good? Weirdly the bike was running prior to the rebuild so im unsure what to think. I assume performance would have been effected? The head is showing no signs of damage nor is there any damage to the piston! What do you guys suspose happened? Everything seemed to be going so well until today Are there any kind folk have a spare power valve doing nothing? I get the feeling this part will be hard to find as it's almost 22yrs old! Bike so far.. (head has been removed since this picture was taken) Any help appricated peeps!