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Discussion Starter · #1 ·
I was wondering how to sync the carbs on the 08 550 lx. Never did it before, so any help is appreciated. Any special tools needed? First time cleaning the carbs so this is all new to me. Thanks

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This starts after you have them cleaned and mostly re-assembled. Kind of...

To sync:
Leave the key out!! (So somebody doesn't try to start it on you.)
Remove carbs from engine. Pull out slides and inspect the slide and make sure the needle jet isn't damaged or bent.
Insert the roundslides, snug the top retainer that the cable goes to. Do not install them on the motor yet.
Operate throttle to wide open and make sure slides are opening all the way. Just enough that the slide isn't seen in the venturi when looking straight through. (Also make sure the slides move smoothly)
Put a zip-tie on the throttle to hold the slides open approx. 3/8-7/16" (on the engine side).
Using GOOD drill bits, find one that just rubs between the bottom of the venturi and the slide (again on the engine side)(You may have to adjust zip-tie to get a perfect fit)
Adjust the other to match by using the adjuster on the top of the carb.(Make sure you aren't pulling on the cables or it will be off)[/color=red]
Make sure slides open and close all the way again and are still smooth.
Take zip-tie off. - Very important!!! [/color=red]
Mount carbs.
The rest is done on the air box side of the carbs.
Again, using drill bits,
Adjust slides so both are at the same height at idle position.(Adjust using idle speed screws on the side of the carbs.)
You may have to adjust the idle again after you start it. (At idle position, there should be just a very small opening through the carbs. Better to start off low then over-rev and have clutch engage and run through wall.
Your idle mixture screw on the side of the carb---start at 1 1/2 turns out from seated.
If you get a bog when snapping the throttle, start turning in the idle screws 1/8 turn at a time until it clears. If you are under 1 turn out, you need to get a size larger pilot jets. (1/2 turn for flatslides)
As you adjust your idle mixture screws, the rpm's will go up or down. Re-adjust idle speeds.
Adjust to get smooth idle quality.
Make sure when you are adjusting the idle speed, you turn all screws exactly the same or the sync will be off.

Have patience, as it may take a while and you may have to re-do it a couple of times to get it perfect.

Hope this helps
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