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Author Topic: Synchronizer manifold fittings?  (Read 609 times)

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Offline soonerbillz

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Synchronizer manifold fittings?
« on: August 23, 2023, 08:06:42 AM »
What size is the threaded fittings to attach my gauges? By that I mean the thread size.
 Also best place to purchase them.
This is on my 75 cb400f.
Thanks!
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Offline Flyin900

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Re: Synchronizer manifold fittings?
« Reply #1 on: August 23, 2023, 08:20:50 AM »
Motion Pro may have a set for the vacuum gauges and not sure of the sizing, usually one for Honda and one for other bikes.
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Offline calj737

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Re: Synchronizer manifold fittings?
« Reply #2 on: August 23, 2023, 08:26:43 AM »
Often 5mm, 0.8 pitch.
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Offline soonerbillz

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Re: Synchronizer manifold fittings?
« Reply #3 on: August 23, 2023, 09:43:31 AM »
Thanks all!
 Part found and ordered!
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Offline Don R

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Re: Synchronizer manifold fittings?
« Reply #4 on: August 23, 2023, 09:54:37 AM »
  The Morgan pro that I bought came with plastic ones, I wondered how long it would be before I cross thread one.
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Offline Scootch

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Re: Synchronizer manifold fittings?
« Reply #5 on: August 23, 2023, 10:09:35 AM »
I permanently installed these in every carb so that I don't have to install and remove connections every time I do carb sync.  One of my carbs was already stripped.
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Offline robvangulik

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Re: Synchronizer manifold fittings?
« Reply #6 on: August 23, 2023, 10:30:30 AM »
I made my own years ago, also permanently installed
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Offline Deltarider

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Re: Synchronizer manifold fittings?
« Reply #7 on: August 23, 2023, 11:58:26 AM »
Out of curiosity, Rob, I had all 4 vac ports connected like you and you were right: it doesn't make a difference.
Only... I wasn't so lucky with my tubes: later I wondered why my bike didn't respond anymore like I was used to. Turned out two of the tubes had slipped free from the adapters because of the heat. So two cylinders were sucking in extra air.  >:(
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Synchronizer manifold fittings?
« Reply #8 on: August 23, 2023, 01:47:39 PM »
Quote from: Scootch on August 23, 2023, 10:09:35 AM
I permanently installed these in every carb so that I don't have to install and remove connections every time I do carb sync.  One of my carbs was already stripped.

Uh Scootch, where is the link?
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Offline Scootch

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Re: Synchronizer manifold fittings?
« Reply #9 on: August 23, 2023, 02:51:38 PM »
Sorry here is a link
https://www.motionpro.com/product/08-0218
It looks like they are out of stock
But many places have them. 
https://www.powersportsid.com/motion-pro/vacuum-adapter-mpn-08-0218.html?vehicle=162337

There are 2 sizes - 5mm and 6mm. Make sure you get the right ones for your carbs.  For the inner 2 carbs I used the length of tubing to bring the connection out to where it was easy to get at.  Also as added insurance against the vacuum leak I use thread sealant when installing these nipples. The 5mm are for 750 and many other bikes. 
« Last Edit: August 23, 2023, 03:15:59 PM by Scootch »
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Offline willbird

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Re: Synchronizer manifold fittings?
« Reply #10 on: August 23, 2023, 03:36:28 PM »
Quote from: Scootch on August 23, 2023, 10:09:35 AM
I permanently installed these in every carb so that I don't have to install and remove connections every time I do carb sync.  One of my carbs was already stripped.

Some folks have advocated for drilling and tapping the nipple end of these and using a screw and a red fiber washer to seal them between uses due to the rubber caps sometimes going bad.

Bill
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Offline Scootch

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Re: Synchronizer manifold fittings?
« Reply #11 on: August 23, 2023, 03:45:54 PM »
Yes we always have to be on guard against those pesky vacuum leaks
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Offline robvangulik

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Re: Synchronizer manifold fittings?
« Reply #12 on: August 23, 2023, 03:53:17 PM »
Quote from: Deltarider on August 23, 2023, 11:58:26 AM
Out of curiosity, Rob, I had all 4 vac ports connected like you and you were right: it doesn't make a difference.
Only... I wasn't so lucky with my tubes: later I wondered why my bike didn't respond anymore like I was used to. Turned out two of the tubes had slipped free from the adapters because of the heat. So two cylinders were sucking in extra air.  >:(
I used an original Honda carb tube, that can stand the heat.
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