Hi guys. First post here, and I just got a new to me 1998 ZX-9R. I've been reading and searching a lot, and there seems to be more information here than on other forums.
Please bear with me, because this will be long as I want to make sure that I cover everything that I've done so far.
I had a problem with it stumbling and hesitating off idle. This made it very hard to start off from from a stop. I had to slip the clutch and keep the RPMs high to keep it from dying. It required a slight amount of choke at all times. At RPMs above about 4k, it runs like crazy. Immediately, I suspected dirty pilot jets.
Here's what I've done so far:
Drained tank and filled with fresh gas
Ran Seafoam through this new tank (No change. Oh well, worth a try)
Removed tank and found engine breather hose completely disconnected.
Reconnected and ran. (slight help, will idle without choke now. Probably coincidence.)
Cleaned K&N air filter.
Removed and disassembled carbs. Relatively clean. Pilots were a little dirty. 3 of 4 diaphragms were pinched by the cap.
When putting them back in, they seemed to be stretched and would not seat correctly. Completely cleaned and re-assembled as best as I could.
Verified that it has stock jets.
Reset AF screws to 2 turns out per service manual (were at 2.5 turns)
Pulled plugs. Looked like a rich condition. All of them were black. Replaced. Stick coils seem to not be seating as tightly as before being removed. They kind of wiggle a little in the hole.
After all of this, it definitely runs better. But, it still has the off-idle hesitation. And if you twist the throttle hard, it will bog and try to die.
So, here's my questions:
Could the diaphragms be causing my problem? The slides seem to work correctly.
Would the carbs being out of sync be the main cause (I haven't synced them yet)?
Side question, should the stick coils seat tightly in the plug hole? I've tried to push them down harder, but it seems like they're bottoming out and I definitely don't want to break them. They're definitely not as tight as before I removed them. The bike runs as is, but it just doesn't seem right.
Any and all help would be much appreciated. Thanks.