Carb Sync Tool

[badgertom]

I realize that some people do not use a Carb. Sync. Tool. But, I would feel more comfortable with such a tool. So, what would be a good tool to use. I am looking at the TecMate TS-111 Carb Mate. (it got good reviews at Amazon.com) Any thoughts ?

[Barry]

No real need to spend much money as nothing you can buy is more sensitive than the $4 manometer or however much they cost to build these days.

[Bob_Roller]

I've used a Twinmax, synchronizer, mercury Carb Stix, wasn't really impressed with using either of them .

I made an oil manometer like Barry has a picture of and that's all I use now .

Takes a bit of learning on how to use it, like after you make an adjustment, wait 30 seconds or so for the manometer to change and stabilize .

I use BMW 7.5 wt fork oil and I think ATF is another common oil used .

[Matt Chapter]

I shelled out for the fancy morgan carbtune pro with 4 ports.. but I have a 4 carb honda too. I like the less clutter aspect compared to a big set of tubes.

Haven't used it on the R65 yet, but I have heard some anecdotes about low vacuum that takes a little fiddling.

[Dustybin]

I have a Morgan as well and the metal rods really dampen out the jumping about well. Used it to great effect on a honda 400/4 which is very susceptible to being off for balance and will chatter like mad if off by even a little.

[Barry]

One fundamental thing to remember about manometers of any type is that the sensitivity of differential pressure measurement is inversely proportional to the fluid density.

With ATF having a density of 0.865 and mercury 13.54  that means for every 1mm displacment on a mecury manometer (which is possibly the smallest pressure differential that could be observed) you will see a movement of 15.5 mm on an ATF manometer.  Damping is an issue of course but with my eyesight it's much easier to see 15.5mm difference than it is to see 1mm.

[Luca]

Another way to dampen the vacuum fluctuations is by using a snubber (restrictive orifice), which should be plumbed as close as possible to the carburetor.  I use 3/16" vacuum line restrictors--available at the local auto parts chain for a couple bucks a piece.  You could also use old carb jets, diesel injector line, crimped 3/16 brake line, etc.

Matt, Morgan says on their website that the tool should be turned upside down because you get very little vacuum at the carb port while idling.  I've checked mine with some grade A liquid filled gauges and they only read about 4 or 5 inches of mercury.  Been meaning to set them up for doing 4 cyl bikes, but it will be a little tricky since I didn't get panel mount gauges  [smiley=wall.gif]

I use BMW 7.5 wt fork oil and I think ATF is another common oil used  

2 stroke oil works great too.

[Tony Smith]

No real need to spend much money as nothing you can buy is more sensitive than the $4 manometer or however much they cost to build these days.

Well said Sir. You are a man after my own parsimonious heart. Why spend money when you can make a more accurate tool for peanuts.
 
The time of re-awakening is rapidly approaching for my own long dormant R65. This weekend I am going to knock up a 9v battery powered "bean can tester" to use both for setting initial static timing and verification that the bean can is functional.

[montmil]

This weekend I am going to knock up a 9v battery...

Not without drinks and dinner first you ain't.

Different meaning here in the Colonies.

[georgesgiralt]

Hello !
While we are at it, I suppose it does not make any difference if the tool is leaning backwards ? I intent to make one free standing with the board hold by a couple of wood stools in order to have the scale at around 15 ~30 ° from verticality.

[Barry]

No problem. The manometer would just be even more sensitive. To ensure fluid isn't sucked out of the manometer you would have to make sure balance was close before using it. It's easy enough to get very close by mechanical means though using feeler gauges on the throttle stops.

I just worked out a 30 deg lean would make it 15.5% more sensitive so it's not a big deal.

[Barry]

Not without drinks and dinner first you ain't

Monte,

If that means what I think it means then it can also mean the same thing here.  

[bruce_launceston]

I used Sthil two stroke oil because it had the best red colour of all the oils on my shelf. Turned out to be perfect viscosity as my manometer with 5mm tubing is very stable and doesn't jump around.

[georgesgiralt]

So I had this nice jig (from a turbo jet engine shop) to use as a sync tool (1.2m high U glass tube with two bottles at the top to gather the mercury if too much imbalance). I had it for years but without mercury, so I decided to try it. (even if I've enough mercury from a broken Torricelli barometer to fill it).
I had red power steering oil left from the car so I thought it could be good.
No joy. The oil is so sticky all the tube is red and I've bubbles travelling from one side to the other.
So I wonder what kind of fluid to use ?
I wonder if the fork oil will behave differently ? Or should I try green liquid coolant ? What do you think ?
P.S. the tubes are glass around 5 mm diameter external and around, say, 3 mm internal.

[Barry]

You need something relatively thin (and cheap) like ATF.  For the even cheaper approach no reason you couldn't use colored water but with a viscosity of 1 it's a lot thinner than ATF  at approx. 7 and would therefore need substantial damping with a restriction or snubber.