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post #1 of (permalink) Old 03-24-2009, 12:41 AM Thread Starter
e1_ZX-9r
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Joined: Sep 2008
From: Blackfoot, ID (~5,000' AMSL)
I Ride: 00 ZX-9r Lime Green 02 ZX-9r Lime Green, California E1 & F1 models, respectively

Posts: 9,979
Post Carburetor synchronization/synchronisation - 45 minute Do-It-Yourself

This should be relevant to carbureted engines with 2, 3 or 4 cylinders. EFI throttle body bikes, review your repair manual's procedure. For 2005-2006 ZX6 TB sync CLICK HERE. A highly recommended Do-It-Yourself, especially if you can borrow someone else's sync tool. It is really that easy.

My used ZX-9r ran poorly at purchase and I performed an eyeball sync* myself last year to smooth most of it out, but it still wasn't perfect. I decided to perform a real carb synchronization and purchased a Carbtune Pro 4 (58 GBP/$85 shipped) after reading good reviews.

Following my Haynes repair manual, I warmed the bike up (140 degrees) raising idle to 1,500 RPM, turned it off, removed the gas tank, connected the sync vacuum tubes to their intake points (below each intake boot), started the bike, sync'ed cylinders 1&2, then 3&4, then left side to right side. That took a whole 2 minutes, so for good measure I fueled the carbs up one more time, blipped the throttle to 1,800 to reseat the butterflies and repeated. The Carbtune made this work out to be child's play.**

No more ruppity-ruppidity. She purrs like a new bike, holding right at 1,100 RPM. Throttle body synchronization theory says that the engine will start easier, run cooler, be more efficient, smoother, with better throttle response & power.

04/2009 1,000 mile update I had to sync her again after some 1/4 mile runs for a Youtube short vid. Dunno why. The science holds true. She runs cool & smooth, starts easy & is a joy to ride. She's very miserly for something so wickedly powerful.
I only wish I would have done this 6 months ago.

*The science behind cylinder vacuum efficiency depends on many factors other than carb/EFI butterfly position; pilot air screw symmetry, pilot circuit clogs/efficiency, minor discrepancies in piston and ring fit, valve opening gap, valve air flow efficiency, carbon build up, temperature, oil weight, etc. Therefore, the only way to accurately synchronize the draw evenly is to use a tool that can measure each cylinder's efficiency.

** Before syncing carbs, always set the pilot air screws symmetrically. If you suspect the pilot air circuit may be dirty, pull the screws, clean the circuit plumbing, set them symmetrically, then perform your sync.

Alright! Trading bikes for a while was fun.I'm ready for mine back. No, seriously, get off my bike. Ahh, what a privilege it is to have such a sweet ride.
At the track she's said to be outclassed, but on the street, she reigns unmatched. She's the only big-bore canyon carving hypermiler I know of. -- Picture gallery, K&N air filter, SuperTrapp Aluminum Racing Series exhaust (Made in USA), ZG touring shield, & otherwise stock.
Science & OODA literate. ACA covered.

Last edited by e1_ZX-9r; 05-17-2010 at 09:23 AM.
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