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Author Topic: Setting sync without a sync gauge 1977-78 CB750  (Read 10732 times)

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Offline trueblue

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Re: Setting sync without a sync gauge 1977-78 CB750
« Reply #25 on: April 06, 2012, 06:34:47 am »
and you look at this tool with your eye,,i think its been mentioned above that the idea of carb syncing is to balance the actual vacuum between the cylinders not actually get the slides at the same height,which will get the bike running ok then use a vacuum method,leaving them set where the precision instrument aligns them is precisely wrong.

Your eyes and a visual inspection is the first step to any mechanical or welding procedure.
I do understand your concerns about the amount of vacuum being created in each cylinder.
It's a case of using the right tool for the right job.  The verniers are the right tool for initial set up but not for fine tuning,  for fine tuning you use the vacuum sync to get it just right.
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Offline lucky

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Re: Setting sync without a sync gauge 1977-78 CB750
« Reply #26 on: April 24, 2012, 03:55:57 pm »
Today I found out that you guys were right but most important I found out WHY.

Please see my post today.
http://forums.sohc4.net/index.php?topic=105823.0
« Last Edit: April 24, 2012, 04:36:31 pm by lucky »

Offline lucky

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Re: Setting sync without a sync gauge 1977-78 CB750
« Reply #27 on: May 01, 2012, 11:00:10 pm »
You have probably been very lucky. The vacum synch allows for the inevitable variations that can be found between cylinders and carbs. The dial gauges prevent sucking liquid into the cylinders. When you go through the synching process is that as you synch a carb the carbs around it change. So you finally tweak them all to  get 1 3 4 even with 2. Your method does not allow for this.

You may be close enough so the differences are negligible. It is not microsurgery.

I bought the dial type sync gauges and I really like them compared to the mamometer with fluid.

 

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