My black dc2r

[butterfingers]

A tune will solve all your problems

[infurNOS]

Im not really definite on 4-1 although i have heard there recommended more for track as they give more midrange and top end but in some cases you may sacrifice some power down low, where as with 4-2-1 you get better low and midrange..

please correct me if im wrong lol

I have 4-2-1 on my DC2R now, midrange isnt that impressive. Maybe im just use to it.

[butterfingers]

i believe almost all free flowing exhausts on a small engine like this will sacrifice low end for high end, unless you have a tune.

try shooting water through a narrow straw, and a big easy way straw. first do it applying light pressure, and then again blowing hard (LOL)

the opposites are true at each end of the scale

[bboyzell]

You sure? Valve clearance adjustment won't make any noticeable change in performance unless you make the clearance too tight. In which case the valve does not fully close, causing loss of performance.

Ya that what the problem was, the 2 out of the four exhaust valve had no gap between it and the cam.
Feeler gauge couldnt get though at all.