exhaust question...

I have a 1979 KZ650C with only 4200 original miles on it. I have had it for about 3 years. It sat for quite a few years before I became in possession of it. Everything is stock all the way down to the original paint. When I first purchased it, the 4-into-2 exhaust was completely rusted out.
I purchased a jardine 4-into-2 exhaust for it and was by jardine that the carbs did NOT need to be re-jetted with their exhaust.

Is this true? I have a really hard time starting the damn thing. I have replaced the fuel lines, petcock,accelerator pump, rebuilt/cleaned/and synced the carbs. The timing is set to specs as well as the advance. The gas tank has aslo been thoroughly cleaned and re-sealed.

Could my problem with starting this bike stem from the jets in the carbs?

Any, and all help would be greatly appreciated. I am mechanically inclined, but I am a newbie to bikes.

Thanx again

A jetting problem would not prevent you from starting the bike. If the bike needed to be jetted it would not run right or pull to redline but it would start. You say it's hard to start, does it start? How does it run ? I would check the basic stuff first, got spark? Fuel? Compression? You would be amazed at how many people "clean" carbs but still miss a lot of gummed up crap in a passage way. The little straw on the carb spray needs to go into every little hole in the carb and come out the other side! (wear safety glasses) The tiny holes in a pilot jet can mess everything up, I used a magnifing glass to make sure they were clear... but check the basics and narrow it down to exactly what the problem is... let us know.


PS, not sure if your familier with these bikes but choke on and NO THROTTLE when starting these beasts!