Topic: Carb syncing

[DV Red Herring]

Has anyone used the motion pro manometer? My carbs were bench synced when I rebuilt them and work pretty good but now I am looking to get them spot on. What is everyone using to properly sync them?

[Johnie]

After the bench sync I use the Morgan Carbtune to get them spot on.

[seanbarney41]

I own the motion pro tool and have used it dozens of times.  Having also used the Morgan that Johnie posted, I'd recommend the Morgan.  The MP has the extra hassle of requiring calibration every time it is used and the Morgan is just built more solid imo. 

Another thought about vacuum syncing in general, if you only have the budget for a carb sync tool or say tires, and not both, get the tires.  The vacuum sync only affects the idle and after a careful and correct bench sync your bike will should run and ride just fine.

[carnivorous chicken]

Morgan is way better. Motion Pros get bubbles and flutter and are crap. I check my carb sync every year or so, and find there are occasional adjustments to be made so it's worth getting a good tool.

[dave500]

before you vacuum sync be sure your ignition is set spot on,bench sync is ball park to get you running,then vacuum sync,once set itll stay put for years.
I like gauges,you don't need fancy colourfull dials but you do need dampers to slow the rapid needle response,it doesent matter the reading but that they all are the same.

[seanbarney41]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

[PeWe]

+1 for checking the ignition first. If 1-4 vs 2-3 points are set different it will idle uneven. Synch carbs will not help then.

There are good info here about carb tuning, ignition etc.
http://www.hondachopper.com/garage/garage.html

[Deltarider]

Has anyone used the motion pro manometer? My carbs were bench synced when I rebuilt them and work pretty good but now I am looking to get them spot on. What is everyone using to properly sync them?

Haven't touched my set in decades since I, like you, was succesful in benchsyncing (in my case within 2cm Hg of eachother when tested afterwards). My advice would be: first compare the underpressure you have now by just attaching a single manometer to one carb after the other. If the four carbs are within spec, why spend money on a vac. set that you'll - unless you have a fleet of bikes - use only once? Once set, forget. BTW, would any of you guys know how carbs were synced at the factory?
I agree with Dave and Pewe: a small difference in ignition timing will impact a nice idle.

[dave500]

poor ignition can waste you hours plus 5/10 free horses!

[DV Red Herring]

Ive got the ignition pretty well dialed in. Two things I don't have tools to measure is is the vacuum sync and ignition dwell. I bench synced them, but I havent had an opportunity to check the vacuum values of each one. The bike idles well, down to 1000 rpm.

[iFart]

I built my own with clear tubing, plastic t barbs, and ATF. Does the job.

[DV Red Herring]

Hey Fart, I love making my own equipment. Can you elaborate on how you did it? Maybe a little "how-to" class?

[carnivorous chicken]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

Individual results may vary of course, but I think the preference for Morgans is pretty well documented and the strength of the dollar to the pound is another incentive. I've seen Motion Pros go for $125, Morgans can be cheaper.

[seanbarney41]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

Individual results may vary of course, but I think the preference for Morgans is pretty well documented and the strength of the dollar to the pound is another incentive. I've seen Motion Pros go for $125, Morgans can be cheaper.

yeah, when I bought my MP set they were about $30 less than the Morgans, now the Morgans are as cheap or cheaper and I agree that the Morgan set is better constructed and easier to use.  I think the MP set is actually more accurate, unfortunately so accurate that it's sensitivity makes it harder to use.

[carnivorous chicken]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

Individual results may vary of course, but I think the preference for Morgans is pretty well documented and the strength of the dollar to the pound is another incentive. I've seen Motion Pros go for $125, Morgans can be cheaper.

yeah, when I bought my MP set they were about $30 less than the Morgans, now the Morgans are as cheap or cheaper and I agree that the Morgan set is better constructed and easier to use.  I think the MP set is actually more accurate, unfortunately so accurate that it's sensitivity makes it harder to use.

It's easier to travel with too!

[seanbarney41]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

Individual results may vary of course, but I think the preference for Morgans is pretty well documented and the strength of the dollar to the pound is another incentive. I've seen Motion Pros go for $125, Morgans can be cheaper.

yeah, when I bought my MP set they were about $30 less than the Morgans, now the Morgans are as cheap or cheaper and I agree that the Morgan set is better constructed and easier to use.  I think the MP set is actually more accurate, unfortunately so accurate that it's sensitivity makes it harder to use.

It's easier to travel with too!

very true, although I can't really think of a time I was wanting to do a carb sync out on the road

[carnivorous chicken]

Motion Pros get bubbles and flutter and are crap.

have not had any problems of the sort

Individual results may vary of course, but I think the preference for Morgans is pretty well documented and the strength of the dollar to the pound is another incentive. I've seen Motion Pros go for $125, Morgans can be cheaper.

yeah, when I bought my MP set they were about $30 less than the Morgans, now the Morgans are as cheap or cheaper and I agree that the Morgan set is better constructed and easier to use.  I think the MP set is actually more accurate, unfortunately so accurate that it's sensitivity makes it harder to use.

It's easier to travel with too!

very true, although I can't really think of a time I was wanting to do a carb sync out on the road

I don't bring it with me on rides, but I have bikes in Phoenix and Seattle, and work on bikes in both places...

[dave500]

mobile on site carb sync?$150.

[DV Red Herring]

Dave500, you may have found a niche in the market!!!

[dave500]

yeah trouble is youll get there and discover the bike has #$%*ty ignition,shot cam chain and valves need adjusting,thatll be $687.33c!

[DV Red Herring]

I like your train of thought. That'll teach them to do the 3k tune up for sure.

[iFart]

Hey, me too!

Here's some links that should get you started in the right direction.

http://forums.sohc4.net/index.php?topic=99882.0

http://www.hondatwins.net/forums/33-tune-up/27587-diy-home-made-carburetor-synchronizer-manometer.html

Check the googles for "diy carb sync" or "diy manometer".

I went with the board idea with clear aquarium tubing, stores easier than a bunch of bottles. Went ATF cause red is easier to see than bluish motor oil. For the screw plugs that go into the carbs I took brass connecting barbs and threaded them with tap/die. They also sell the connector pieces in a kit which is a bit more convenient.