Questions About The Design of the Stock KZ650 Exhaust System

Please see post below.

I like the looks and sound of my 1982 KZ650 CSR stock exhaust system, but have tried a 4 into 1 system, with a significant horsepower increase. I believe the stock system limits power in the following ways: (See photo below)
1. The pipe for cylinder #2 enters pipe #1 at almost 90 degrees, rather than a smooth "Y" configuration. Ditto for 3 & 4. Also the system "necks down" to less than the diameter of either of the two pipes, and has the cross pipe tied in very close to this intersection.
2. The effective pipe length for cylinders 1 & 4, is about 40", while 2 & 3 are about 26". 1 & 4 pipes go back into the megaphone about 7", while 2 & 3 dump into 1 & 4.
3. Considering the 1-2-4-3 firing order, I would rather cylinders 1 & 4 were coupled together and 2 & 3 together, rather than 1-2 and 3-4 with the stock system. This would allow an even spacing between firing for each side of the system, instead of the stock "left-left" and then "right-right" firing.

For items 1 & 2 above, I am considering building a "Y" collector for each side, that goes into a 2" pipe that will be welded into the front end of the megaphone. This should relieve much of the back pressure of the present system, and make the length equal for all cylinders.

Item #3 would require a crossover of pipes such as the SR system, or the ZeCross system sold by Z1. --> www.z1enterprises.com/detail.aspx?ID=3220

I CANNOT UNDERSTAND WHY THE STOCK COLLECTOR NECKS DOWN SO SMALL AND JOINS AT SUCH ABRUPT ANGLES. Can someone explain any benefits to this design and what ill effects may result if I do the "Y" collector modification? Thanks everybody.[/quote]

del

The cross over pipe helps with the bottle neck, it feeds some of the exhaust to both mufflers and eliminates some of the excessive back pressure.