07 yz250f is making a clicking noise at idle

Hi, not sure from that end but how many km you have on that car, cose if it done 100,00.000-120,00.00 km You realy should pay attention or replace your timing belt, cos the noise you hearing could be from there not your valves, but if not changed in time the damage from that could escalate on that car to anywer $2-3 K, eazy. Anyway it just a thout 4 you. G/luck.
Tony

You could put a tiny bit a Auto Matic Transmission fluid in the oil for about 10 miles and then replace the oil with a little thinner viscosity oil. for example if you use 20-50w change to 10-30w. If they continue to make noise, replace them. They should not be too expensive, though it is a Porsche, lol

If the 'clicking' sound changes with engine speed you need to check your oil, and pay attention to your temperature guage-it might be a lifter making noise and an oil change would possibly help. If it is a steady clicking noise, it might be a loud fuel injector, possible but not likely.

CARL SALTER

Best bet: Have a mechanic listen to it. Usually they don't charge for a quick listen.
But, if you don't want to do that...

Clicking/clattering noise? Most commonly this happens if you went to long between oil changes, or overheated.
Change your oil AND filter, and use 15w40 'universal' or 'ci-4 plus' grade oil for one or two oil changes, then go back to factory spec oil.

CI4-Plus / Universal oil has more cleaning properties and helps to get rid of varnish and sludge. Usually, loud clicking/clattering/clacking is caused by the hydraulic lifters sticking or not getting oil for some reason. Cleaning out the sludge and varnish very often helps this. If you're really picky about it, use your favorite search engine and find the AutoRX site, that stuff is comparitively expensive and must be used according to directions, but, in my opinion, it is well worth every penny.

If you live in a very cold climate, you might want to wait for summer first, as this is a thicker oil than factory spec and will make for slightly harder starting and a tiny bit less MPG (aaround 0.25 MPG less here in Houston, which is NOT a cold climate)

I see: you changed the plug because it was backfiring.

Does it back fire when you let OFF the throttle after revving it, or does it back fire while being revved?

If it does it when you let off then Ollie's suggeston might do it. If that doesn't do it then check for dirt in your pilot jet.

If it back fires when revved up high could be dirt in your main jet.

No guarantees, but it may just be that oil is draining back into the pan when the car sits. Once you fire it up, it knocks till the oil is pumping again. Especially if it only does it after the car has been sitting for hours and hours. Good Luck!

You need to oil your cables first....They make a gadget to help you do this...it clamps around the end of the cable, and you spray oil into a provided hole for a spray nozzle tube...Then see if the cables are unstuck by turning the throttle grip back and forth for awhile....start it and see if that helped....if not you may need to replace the cable(s)...I doubt that the slide in the carb is hanging up...or valve.If this doesn't work notify me.