I just bought a 01 Dina lowrider it has screaming eagle heads Vance and Hines slip on and a high flow filter with a makuni carb looking for help tuning it jet sizes pump nozel size and needle placement as well as what needle to use bike starts and runs however as far as proformance wise can't go past half throttle with out it feeling like I louse power if I back off it it will come back not Shure where to start with it

 

Trying to figure out if this is real. far be it from me disect spelling.

 

Its real sorry not the best speller

 

Anytime you lose power but it comes back if you let off then you're lean. After it's warmed up try going to full throttle and see if it takes off. If it does then the main might be okay. If it bogs still then I'd go up two sizes to start off and see what happens. If it does take off and run strong then your needle is too low. I would raise it two notches to start off. If you don't have the Mikuni tuning manual you can get it on their website. It's very good for fine tuning once you get it to run decent.