thanks for your response but it runs bad with two different carbs one of them is new.It does the same thing with both ones.. The cns which ran good for about 8 months and so I thought it was the carb adjusted float checked jets and adjusted needle seats all of them...no better.So last week I put a new nt on same problem...If it's running rich, you could try adjusting the float, and because your spark plug is wet, the engine may be running rich. So you've got no mid-range power? Try pulling off the air filter, then start the engine, warm it up, and go for a quick ride. See if you notice something. That's what was wrong on my bike (float setting and air filter, NT Carb). One more thing. I've heard somewhere else on this forum that a bad spark plug may spark when you test it outside the cylinder (visual spark test), but under pressure in the cylinder will deliver weak/no spark. Spark plugs are pretty cheap and the stock one is terrible anyways. Just something to consider...