250-500cc Engine knock

I have 14 wr300 and it has a knock at higher rpm's. I ride alot of single track in 1st and 2nd gear so i wind out the gear pretty high sometimes, when i do i get a single "knock" sometimes. Its not a consistant knock like gear issue or bearings. the jetting is good a little on the rich side. I was thinking maybe something with the powervalve. Has anyone had this noise?

thanks pat

If I dont have good fresh gas mine will knock under heavy load. Not race gas just fresh premium Shell pump gas. Stock bike and its a 250.

I use premium fuel from quick chek, and its usually 3 weeks old

I find the more i ride the more weird worrying noises i hear so far all it comes down to is 2strokes bash out strange noises had a detonation sound on high rpm's but i rev harder it disappeared anyhow it was piston slap so that whent when i canged the slug, 14plate bike i should hope the slugs good for a while longer yet tho.

Keep an ear out for it if it gets worse start worrying otherwise go ride it.

i hear ya i drive myself crazy with worrying about noises. Im guessing you ment plug when you said "slug" haha

No i ment slug piston is refered to as slug as its a slug of cast metal

oo i see!! my bad

No bad its just another term wich some people use it my make a few more of posts understandable now.

Remove the reeds and look at the intake side of the piston. If the intake port has worn grooves on the rear piston skirt then it's time to change the piston before it breaks and screws everything up.

I finally got time to look at my piston, and it looks good so I took my left side power valve cover off and looked at that. I will probably just ride it and enjoy.

looks good!

That looks about like mine did at about 200 hours. It's worth checking at least every year because once it starts to wear it will go fast. I think the 250s are much more reliable than the 300s in respect to piston wear on the intake side.

thank you i will check it periodically as the hours go up