I have got a new engine for my bike today. After riding out of the mechanic I found it was completely different to my old engine. I get more torque at lower revs but at higher revs it seem to be less than my old engine. Unfortunaly I found something stange about it. In first gear and sometimes in second gear at 8000rpm the engine seems like its not getting enough fuel. In first gear most of the time when I hit 8000rpm it just stop accelerating and I have to put on more throtle to get it accelerating again but after 9500rmp its fine again and accelerates like my old one. I am not sure if its normal or is there something wrong. The carby is different than my old one. They said that its abit narrower so I get more torque at lower revs. I did get this but im not sure if it effected my engine like I described. Also the differance is the old engine had racing plugs in them(iridium plug) the new one had standard plugs put in. Other than this small problem the engine is quite good. I just realized what I was missing with my old engine. Any ideas on what might be going on?