TOPIC:

i installed a 4 into 1 header with kerker muffler on my 81 kz650 H1. the original pipes had the cross pipe that went bewteen the 2 sides underneath the oil pan welded shut. (bolts in the holes and welded in) now since everything is going into one pipe, should i make any carburator changes or any other changes?

Need more info, bike stock was it running good prior to the kerker, what carbs are on it, ect.

Because the aftermarket exhaust may be more efficient scavenging than the stock pipe was, you may run a little lean after installing the pipe - at least that what headers are supposed to do - allow more fuel air mixture in by removing exhaust more efficiently. Look at the plugs if you know how to read them, see how it runs. If it seems starved when you whack the throttle open, or pops, or wants choke, then try a larger jet.

It just takes time to get right.

Curtiss

iirc, when i put a kerker k2 on my '81 kz750, i went up 2 sizes on the mains and left the pilots alone.

the bike was mostly stock before i had put the headers on, it ran pretty well from what i know. this is my first bike and i went through every test and "calibration" i could find after getting it running. as i said the original exhaust had been modified to where the cross pipe between the two pipes was eliminated so essentially #1 had their own exhaust so did #3. now that i intalled this header. it seems to run faily decent but once she really warms up and im on the throttle about 60% i can hear a very uneven tone if that makes sense. like its just not in tune is the best way to put it. i have lots of crackling decelerating. reaching down and holding my hand over the exhaust and smelling it, it smells lean. not gassy at all more like oil and hot metal is the best way to explain it. i was thinking about taking the carbs that were on the bike i got the exhaust from and putting them on my bike since it might have been jetted for the exhaust. it was an earlier kz650. the frame says a 77. my carburetors have the accelerator pump bypassed with a different float bowl on the main carburetor and the lines capped or tied to eachother between the float bowls. as i said it seemed to run fine before but not its very uneven and does seem starved. it has been sitting all winter as well. the current carbs are mikunis. the ones that came off the parts bike are as well just with no accelerator pump. they both did have pod filters as well no air box unfortunately