1978 KZ650 running issues

I surprised no one has mentioned about your earlier post that you replaced all the brass parts. EBay jets and needles are Chinese crap and cause more problems than they solve. Jet and needle flow rates are Critical. Use only genuine quality controlled parts which can be easily identified as they have the mikuni logo stamped next to the size on the jet. 
Ditto pod type filters. Use only well known brand filters or as previously mentioned air flow to the pilot circuit can get blocked. 
Don't skimp on carb work. The best built engine in the world will run like crap unless it gets the correct amount of fuel and air at the correct time. A colour tune will tell you what is happening with the fuel air mixture for each cylinder when the engine is running. 

@TexasKZ - I bought them off Z1. They probably aren't genuine K&N Pods. Why don't you like anything but those 3 brands?

@Warren3200GT - Is it a difference in materials or just quality control that you don't like about the cheaper parts kits?

Just curious.

 

Flow rate on jets, correct taper on needles, govern the amount of fuel/air that enters the cylinder.
I have checked the flow rate of many sets of ebay "rebuild" kits and found them to be as much as 40% out from stated jet size flow rate even from each other in the same kit.  Imagine what that'll do if fitted to a set of carbs. Some would be lean some would be rich and you wouldn't have much of a chance of setting them up correctly. 
I would rather properly clean the originals or pay more and buy genuine new than even consider those rebuild kits. 
Genuine jets and needles don't really wear out so why risk poor quality for such critical parts. 
Check your original parts have the mikuni marks, clean them properly, bin the kit parts and just use the gaskets and o rings from the kits. 

Or spend your time chasing issues you won't solve. Your choice! 

wrote:

@TexasKZ - I bought them off Z1. They probably aren't genuine K&N Pods. Why don't you like anything but those 3 brands?

@Warren3200GT - Is it a difference in materials or just quality control that you don't like about the cheaper parts kits?

Just curious.



 

I know for a fact that those three companies sell high quality filters. I havread numerous threads here and at ZRXOA about problems encountered with cheaper filters. Some block the air jets, others use filter material that flows far less, yes less, than the factory setup. I have no experience with the Z1 filters. They may be fine, or they may cause problems. I hope they are good.
I have also seen some threads about problems encountered with cheap aftermarket jets. Warren3200GT is correct about the importance of accurate machining. It takes very little error to significantly alter the mixture.