Carb sync

[pancho]

For those of you that are thinking of building the six tube manometer here's some points to be aware of:

1. The PVC reservoir is the only common connection between the tubes.  Do not "T" any tubes together.

2. Using a light weight fluid will cause the levels to jump up and down a lot.  Mercron ATF dampens the jumping and seems to work best.

3.  All six tubes must be connected before starting the engine; otherwise air will be sucked into the tubes that are not connected and cause the ATF to get sucked right into the carbs that are connected.  Makes a great insect fogger. :-)

4. When you adjust one carb, you will immediately seen an effect on the others.  Keep tweeking until they are almost all the same.  An inch or two difference is plenty accurate.  Remember, you are doing this at idle.  When you are riding above 2,000 RPM it won't make that much difference.

5.  When doing this procedure, run a window fan in front of the radiator.

This is the way I want to go,,

I can't quite figure out that PVC reservoir setup,,, it seems that all six tubes need to be able to lift fluid (ATF) from a common source, and that source must be vented to atmospheric pressure... is that correct????

[Ricky-D]

Is it best to sync at idle or 3000 rpm? I have read both

Anything that suggests to synchronize at that high level of idle is misinformed and does not reflect the actuality of how the carburetor functions.

Idle at 1000 rpm's is the recommended speed and it is emphasized to maintain the same idle speed throughout the synchronizing process.

Honda recognizes that the bike tachometer is not a good agent for a synchronization and they themselves recommend a good quality tachometer to achieve a good result.

***

[fudgie]

I do mine at idle.

[Gavin_Sons]

Im the proud new owner of a 6 gauge set.
 http://item.mobileweb.ebay.com/viewitem?itemId=110874587472&index=0&nav=SEARCH&nid=40543985946
And I got another set of 2. Hooked them to # 3 and they read pretty damn close to the same.

[hoosier jaybird]

Concerning the sync manometer, what size tubing was used for the vacuum sight gauges? How critical is it to have the tubes on the liquid manometer in the upright or plumb position? Also have you installed needle valves to dampen fluctuations in the liquid levels? I'm surprised 1" variation is acceptable, is this system that sensitive? Thank you.

[Gavin_Sons]

Jaybird, I didnt have the time to make the liquid manometer like some are using and making so I just bought a set. Im planning on testing them out this weekend and if all goes well your more than welcome to come here and do yours, not sure where you are in indiana, I have all the tools.

[hoosier jaybird]

Thanks Gavin for the offer, I actually have a ready made 4 gauge set but was wondering if the liquid type was more accurate. I'm about an hour south of Ft. Wayne and I have a brother lives just outside Columbus and will probably ride down some weekend when it gets a little nicer. The pilot screw thing I haven't attempted yet and I read 1 thread says to do that before syncing the carbs. I may take you up with some help.

[Gavin_Sons]

If you ride down sometime let me know and maybe we could get together and ride a little. Im just south of columbus, about half way between columbus and seymour.

[hoosier jaybird]

Gavin, thanks maybe it would work.

[fudgie]

I'm about an hour south of Ft. Wayne and I have a brother lives just outside Columbus and will probably ride down some weekend when it gets a little nicer.

Marion or Muncie?

[hoosier jaybird]

Fudgie, where you had you PGM last July. As a side note, Nick's dad told me that Nick had found a bike on line and his dad was going to see about getting it so it would be waiting when Nick got home. Sadly this was about a week before Nick was killed. His dad rides a full dress Harley. I'm sure they would have had good times together.

[Ricky-D]

I don't think the pilot screw adjustment has any affect on the synchronization of the carburetors whatsoever.

The synchronization is affected by throttle position and rpm's, nothing else.

The ability to maintain a good idle speed (rpm's) is definitely a function of the pilot screws but regardless, it's possible to synchronize a setup with gummed up jets although not pratical and still get a good synchronization result.

***

[fudgie]

Fudgie, where you had you PGM last July. As a side note, Nick's dad told me that Nick had found a bike on line and his dad was going to see about getting it so it would be waiting when Nick got home. Sadly this was about a week before Nick was killed. His dad rides a full dress Harley. I'm sure they would have had good times together.

Oh thats right I remember us chatting about that. I forgot. 

Oh wow. Heartbreaking.

[salty1]

Is it best to sync at idle or 3000 rpm? I have read both

I believe the service manual says 1000 rpm and readjust the idle as needed.  ???

[PSUbag]

I don't know if there is a link to using the single gauge,but, its been brought up many times.
I just use a single gauge connected to #3. In that vacuum line I stick in a ' T ' . Tubing is connected to every intake [marked/numbered] and run to the rear and plugged with golf tee's. Whichever cylinder you start with, connect it to the ' T '. Clip Forceps on that line and read #3. Clip off #3 and read/adjust the other cylinder to match #3. Continue with all cylinders. If fan comes on, wait till it stops before adjusting. Keep engine speed the same thru out this procedure as it may pick up doing this. Blip the throttle after each adjustment. I go thru them a couple times. It took longer to write this than to do it. Just try to make sure that the correct line is clipped off and that only one line is being read at a time. It can be easy to forget and read both lines or the wrong line.
Good vacuum gauges will have a damper, if not, you will need to restrict/pinch the line to it until the needle just barely oscillates. I don't like to restrict until the needle stops, I like it always moving just a bit.

Thanks for the response. Sounds simple enough for me to attempt   

[Oklahoma_Valk]

I bought a 4-column Morgan Carbtune this year. Love it. Best money I have spent on a tool

$112 shipped from the U.K.

The quickest way to make new friends is to build/buy a carb sync tool.

[Gavin_Sons]

I got a full set now, thinking about trying them out tomorrow.

[Patrick]

PSUbag, you're welcome. Once you've done this once you'll see how easy it is. The main thing is to just make sure you're only reading from one vacuum line[cylinder] at a time. It's easy to set each to within .5in/hg. [Honda says 1.6 in/hg]. Its a procedure that should be checked every once in awhile, but, it's not as magical as some think. It is done at idle speed.