help my xr650r sputters in higher rpm range

My uncorked xxr sputters when it enters 1/2 throttle or more in every gear, idles and drives well under low loads on engine. The carb is cleaned, air filter clean, new plug (though old one was very charred), plug cap fine, still sputters.

help

Newfoundland = Sea level ???

Maybe go a bit richer on the needle and main jetting......

What are the current jet specs?

Have you adjusted the valves? How about the timing? Does fuel flow freely from tank? How's your valve spring tension? Has you spark arestor been cleaned? Muffler packing in good condition? Is your vent tube on your gas cap pinched or pluged?

Spark plug science is a wizardry thing IMHO. You're supposed to read the plug down at the base of the hole. So all the way down inside the hole that the electrode comes out of. Make sense?

From what you've said I'd guess low fuel flow. Does it do the same thing when you are sitting still in neutral and winding it up? Could be electrical too. Higher RPM means higher vibration. You could have a connectivity problem somewhere or even have something electric failing at higher vibration.

You could drill out the float bowl bolt and glue a neodymium magnet in the base and then see what kind of crap is in the fuel you're buying.

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