Random knock on start up

So I replaced my valve cover gasket and adjusted my valves. Now i went riding today with my little bro and i did a donut and i accidently killed it because i was gonna flip if i didnt let off the gas. And anyways I went to start it and it sounds like the valve is hitting the piston or maybe its detonating when i start it, it has 89 octane in it right now and it wont do it everytime i start it but only at random times. The quad runs great and everything but i just want some input from you all.

Btw my piston is either 10:1 or 11:1

Mine does it every so often too. Imho its the starter probably grenading itself slowly or just the valves being in such a spot to cause the noise due tot he hot cam I have.

I think mine has a cam too, my sisters 300 with an 11:1 piston and stop cam will sometime do it iirc. I adjusted the valves so they drug on the feeler gauge a little like theyre supposed to.

Quote:

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Originally posted by ridehonda400ex
I think mine has a cam too, my sisters 300 with an 11:1 piston and stop cam will sometime do it iirc. I adjusted the valves so they drug on the feeler gauge a little like theyre supposed to.

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Mines same way adjusted. No issues riding it for over IDK at least 250-350 hours or better.

I guess ill just keep on a riding then. If something goes wrong then oh well, ill fix it lol