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Discussion Starter #1
Hello,
Need some help with which way to adjust the sync screw. It's been a while since I have had this bike running. I can get it started but the right side header is cool to the touch compared to the left side. This is after letting the bike run for about 30 seconds. I figure the carbs are way out of synch after I cleaned them.

So do I turn the adjuster screw counter clockwise or clockwise to get started? I am going to put a synchronizer tool on it as well. It hasn't come in the mail yet though. FYI: this has new plugs and valves adjusted.
-Mark
 

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Carb sync won't help, cold cylinder is not firing, you need to fix that before syncing.
 

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It's not a question of turning right or left per se. Once it's running with the gauges/manometer connected you'll turn one way or the other to get both sides reading identical, close doesn't count. The hard part is loosening the 8mm lock nut and finding a position to insert a long thin screwdriver in to make adjustments. Then being able to hold the adjustment while tightening the lock nut.
Once it's all tightened back up you have to check that it didn't change, tightening the nut will change it most of the time slightly.
 

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Discussion Starter #4
Thanks for the replies. I’m pretty sure I have spark. I had some smoke and popping out of both pipes during the short time it was running. And I tested for spark on both sides a couple months ago.
 

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a light spray of starting fluid in the right side carb intake will let you know if it is a fuel or ignition problem. If it fires off with the starting fluid it is a fuel problem.

Lots of threads on here about "thoroughly" cleaned carbs that end up with carbs not being fully cleaned. Completely clogged passages won't allow the cleaning fluid to flow through and clean them so they remain clogged even when using an ultrasonic cleaner, you need to make sure canned air or spray cleaner can get through all passages. Do not use a wire material that is harder than your carb body or it will damage your passages.
 

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Discussion Starter #6
I was able to spray cleaning fluid through all the passages. I was going to disassemble them again over the winter anyway. I just think the carbs are way out of sync but I'm no expert. It runs, it's just rough.
 

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out of adjustment would cause rough running, not out of sync.
 

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Inspect the plugs for signs of lean/richness , if you pull one plug wire while its running and it stalls/stays running you can isolate a side not producing power ,
Biggest issues i have run into is a lean engine due to clogged pilot jets/passages

Sent from my SM-G960U using Tapatalk
 

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Can you bench sync the carbs on a 400T? Is there a tie plate like on the Cl360? Bench syncing is just an adjustment to make sure the two throttles are resting at exactly the same opening at idle and opening with the throttle at exactly the same time, correct? Syncing with vacuum guages would be the same adjustment but would ensure that both carbs are flowing the exact same volume of air at idle (provided both carbs and cyl are operating properly), seems this would be more accurate than just mechanically bench syncing if both cylinders are running well?

btw... I made an adjustment to my fuel tank to make dynamic syncing much easier.
 

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Can you bench sync the carbs on a 400T? Is there a tie plate like on the Cl360? Bench syncing is just an adjustment to make sure the two throttles are resting at exactly the same opening at idle and opening with the throttle at exactly the same time, correct? Syncing with vacuum guages would be the same adjustment but would ensure that both carbs are flowing the exact same volume of air at idle (provided both carbs and cyl are operating properly), seems this would be more accurate than just mechanically bench syncing if both cylinders are running well?

btw... I made an adjustment to my fuel tank to make dynamic syncing much easier.
Yes, you would bench sync these carbs before installing BUT that only gets you close enough to run, a dynamic (running) sync is required to get them correct.
On these engines there's a vacuum port in the head under the JIS screw, 5mm screw in adapter needed. The carbs have a balance adjust screw in the linkage that's a PITA to get to.
 
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