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Old 09-27-2013, 05:55 PM   #1
cb200t OP
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Location: Bellefontaine, OH
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Carb Sync on an old Honda Twin

I'm having a difficult time figuring out which carb sync tool to get. Many of them refer to a "master" carburetor that is the one the other carbs in the bank are sync'd from. Obviously our twins only have two, and are individually actuated by cables. I am really unsure of what tool to get, and how to sync the carbs I suppose. I know a lot of you guys don't need a tool to do it, but I have zero experience doing anything with a carb, so I feel like I need the extra help. I checked in the FSM and there is no mention of how to sync the carbs in there, or that you even have to, which doesn't seem correct to me. My CB200T has two threaded holes on the intake manifolds already. So I guess my questions are:

Which tool can I use?

I was looking at these:
CarbMate: http://www.amazon.com/Tecmate-TS-111...carb+sync+tool

SyncPro: http://www.amazon.com/Motion-Pro-08-...carb+sync+tool

Basic Gauge: http://www.amazon.com/vacuum-carbure...carb+sync+tool

How do I go about syncing the carbs?
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Old 09-27-2013, 07:10 PM   #2
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Quote:
Originally Posted by cb200t View Post
I'm having a difficult time figuring out which carb sync tool to get. Many of them refer to a "master" carburetor that is the one the other carbs in the bank are sync'd from. Obviously our twins only have two, and are individually actuated by cables. I am really unsure of what tool to get, and how to sync the carbs I suppose. I know a lot of you guys don't need a tool to do it, but I have zero experience doing anything with a carb, so I feel like I need the extra help. I checked in the FSM and there is no mention of how to sync the carbs in there, or that you even have to, which doesn't seem correct to me. My CB200T has two threaded holes on the intake manifolds already. So I guess my questions are:

Which tool can I use?

I was looking at these:
CarbMate: http://www.amazon.com/Tecmate-TS-111...carb+sync+tool

SyncPro: http://www.amazon.com/Motion-Pro-08-...carb+sync+tool

Basic Gauge: http://www.amazon.com/vacuum-carbure...carb+sync+tool

How do I go about syncing the carbs?
I used a 4 gauge version of the basic gauges in your amazon link for my '74 cb550. That's all you need.

First, assuming your carbs have a vacuum screw on the intake side of the carbs, just hook up the rubber hose from each carb to one of the gauges. Generally, you want to sync them at just off-idle. The issue is to determine if you should 'lift' a carb to match the other, or 'drop' a carb to match the other. You want to check you master idle first. Basically, if your master idle is already too high and you drop one of the carbs, then you run out of adjustment on the master. (if that makes sense)

If you have room to raise your master idle (for both carbs at the same time) you should drop the higher vacuum carb to match the lower one, and then bring up the master idle for both. Also, mostly disregard the vac leak warning on the gauges. It's more important to get them equal, then any specific number.

Vac sync can make a huge difference on how the bike runs on lower RPMs. I always knew when my carbs needed sync when the bike wouldn't 'lug' very well without a bunch of drive line lash. Strangely, chain slap on my cb550 was often an indication that my carbs needed sync.

Hope that helps a bit.

(yes, don't worry about the master carb thing. Unless one of your carbs does't have a sync adjustment. Some of the old HOndas had one of the carbs that wasn't adjustable. But I've never seen one)
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Old 09-27-2013, 10:31 PM   #3
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You might get better response in a Forum that has UJMs as it's object. Maybe there is confusion. The term Airhed is a 1970 to 1995 BMW aircooled twin motorcycle. You are an air cooled or airhead motorcycle but we are The Airheads. Sorry. But that is what the term means.

Try this; http://advrider.com/forums/forumdisplay.php?f=11
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Old 09-27-2013, 10:38 PM   #4
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Oop, sorry! Didn't mean to be in the wrong place! :eek: will the mods relocate me?

Sent from my LG-LS840 using Tapatalk 2:eek:
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Old 09-28-2013, 02:35 AM   #5
chasbmw
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To a degree you would use the master technique on a twin.

Do the basic sych getting both carbs close, then lock down the master carb and adjust the slave. This makes it easier on a BMW twin because the adjustment varies when you tighten down the lock nuts.

Airhead content established
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Old 09-28-2013, 04:33 AM   #6
rambozo
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I have the four gauge version of the basic set too, they work fine but you know
they're cheap, if you can afford it I'd buy a better set

Bench synch them first, makes it much easier IMO, you'll find a video on youtube
how to do this, you might even get them close enough you won't need gauges

I've only seen a master carb on four cylinder bikes, usually the second in from the left

Good luck with it
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Old 09-28-2013, 11:29 AM   #7
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Try Hondatwins.net they'll get you to specific instructions.
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