Erratic Idle...
 

Help!!! I just installed a new D&D exhaust system onto my 00 zx9r. Now it won't idle nearly as smoothly as it did defore. The idle used to be right around 1050, but now it dips to almost 900. I know that this new exhaust is less restrictive that the one that came off, (cuz the old one was dented just forward of the midpipe) but can that make it idle like this? Might it need to be rejetted? The instructions say that this exhaust will cause no harm with stock jetting, but they recommend factory brand jet kits. This is a 4-2-1, as was the one that came off. The old exhaust was also aftermarket, but I have no clue as to what brand or model, cuz the bike was laid down by the previous owner (hence the damage) and there's no longer any makrings on the pipe. Thanks for any help you may be able to provide!!!

RE: Erratic Idle...
 

What you must do is synchronize the carburetors. If you don't have a carb-sticks or manometer, you'll probably have to take it to a dealership to get this done.
Jetting is not necessary, but you should also be able to adjust your idle with the knob at the left..
"Less restrictive" does not automatically equal more power. Mr. Kawasaki knows an hell of a lot more about making an engine powerful than Mr. K & Mr. N or Mr. Akrapovic ever will.
-CCinC

RE: Erratic Idle...
 

Thanks for the info... I borrowed one of the mercury type from a friend over the summer, and balanced the carbs then. It ran pretty well, idled smooth the day before I swapped the exhausts. Could it change that much that quickly? Would the exhaust have any affect on it needing to be re-synched? And the idle knob on the left isn't going to fix it, the idle goes up,down. up,down, up,down...whenever it is at idle, no matter if the idle is set at 900 or 1400!!! (I tried) Isaac

RE: Erratic Idle...
 

Where are your fuel mixture screws set at? Those are the screws at the bottom of the carbs and sealed at factory. On my sons 01 zx9 they we're all over the place. You must be very careful drilling out the factory seal, when you remove the seals try setting screws 1-3/4 out. It cured our idle problem, until we installed a factory pro jet kit, then we re-set them to 1-1/2.
The factory settings on our fuel mixture screws were, #1) 1/4 out, #2) 1/2 out, #3) 1-1/4 out and #4) was 1-3/4 turns out. Just resetting those screws really helped idle and off idle to 3000 rpm's. Might be worth a try!

RE: Erratic Idle...
 

I'd yank those f'ers out do a cleaning reset float height and resync. But yes you are on a roll with carb work.

RE: Erratic Idle...
 

You folks know more than I do, so I'll make the carb work my next move. Luckilly, I have a spare set of carbs to practice that drilling on, so I don't end up jacking up my good set!!! Thanks for the feedback!

RE: Erratic Idle...
 

Just make sure when you drill through you don't hit the screws. It's not hard at all, the factory sets the carbs very lean from the get go. My 2001 zx9 was so lean, I was dropping #1 cylinder at idle and had no power til 3k.

RE: Erratic Idle...
 

I used a small screwdriver and a ball peen hammer. Pry up the cap and you have access.