Recommended TB synch tool?

[jviss]

Looking to buy a vacuum gauge set since my son just took his Motion Pro SynchPRO. This is four channel mercury-style carb synch tool. I like the idea of the round dial vacuum gauges; but I have no idea what type is the best price/performance, for both the 'RT, and our other bikes.

 

Thanks,

 

jv

 

[deevee]

I sure like my Harmonizer Vacuum Multi-Tool.

 

Click to --Harmonizer -- link to ADV special price

 

It was so easy to get my 1100RS synced and what a difference it made.

 

 

[WestyLancs]

Seemingly similar operation to the Sync Pro is the Carbtune

 

http://www.carbtune.co.uk/carbdtls.html

 

2 or 4 cylinder versions. I was brought one by Santa last

Christmas and find it a doddle to use. Being steel rods,

instead of liquid for the column fill makes it a bit more

robust IMHO as there's nothing to leak.

[tallman]

Seemingly similar operation to the Sync Pro is the Carbtune

 

http://www.carbtune.co.uk/carbdtls.html

 

2 or 4 cylinder versions. I was brought one by Santa last

Christmas and find it a doddle to use. Being steel rods,

instead of liquid for the column fill makes it a bit more

robust IMHO as there's nothing to leak.

 

Packs easy for Tech days, instructions are in english (well, British english)

and it works with no messy liquids, batteries, mumbo jumbo.

[10ovr]

I have the Carbtune and the Harmonizer,,Both work great,I like the Harmonizer just a little more because of the RPM readout on the screen,,Ether way you can't go wrong ,,,

[dirtrider]

Morning JV

 

Since you titled your thread "Recommended TB synch tool" I presume you are looking for other suggestions as well as round vacuum gauges? (or at least options on alternatives)

 

Good quality liquid dampened large diameter (precision) vacuum gauges cost a lot of money unless you can find some used ones. (maybe E-Bay)

 

Standard (re cheap) undampened vacuum gauges are cheap to buy but offer limited usage on boxer engines with a 360° firing order due to the harsh (opposed) intake vacuum pulses. Most of the cheaper "auto parts store" vacuum gauges are smaller in diameter & calibrated in 1" Hg increments. So even if you can smooth the intake pulses a bit with restrictors you are still looking at oscillating gauge needles that make getting the balance under 1" Hg more of a guess than a precision setting.

 

Seeing as the BMW boxer has a 360° firing order the sides are directly opposed so a simple homemade liquid filled "U" tube manometer is about the most accurate way to do a PRECISION cross side TB balance. Most use water, water/antifreeze mix, or a light oil but all are "WAY" more precision than a standard vacuum gauge reading in inches of mercury.

 

Remember that 1" of mercury (standard vacuum gauge) is equal to about 13.6" of water. Most of us balance our BMW boxers to under 2" of water (that isn't even a needle movement on a standard Hg vacuum gauge).

 

If a person is capable of precision engine tuning then once set & locked down correctly the repeatability of the U tube liquid manometer is really quite good with repeatability of well under 1" deviation after test riding the bike. Some tuners can't seem to get a handle on proper & precision engine tuning so complain of non repeatability of U tube manometers. The repeatability of my personal U tube manometers has been much better than I originally expected when I built them.

 

You mention multiple bikes or multiple engine usage so for other than opposed 2 cylinder 360° boxers you will need a vacuum measuring set up like vacuum gauges or multi channel electronic device that measures against atmospheric pressure. (can't use the pressure delta cross side)

 

Those can be as simple as the old mercury sticks or things like the modern Sync Pro, or Harmonizer, etc.

 

You asked specifically about vacuum gauges so you have some choices on those.

 

I have an old (4) set of H.D. Trerice 0-30" Hg liquid (I believe glycerin) filled gauges that I use on multi-cylinder motorcycles like the GoldWings & the 90° Ducati's. I custom built the manifold to hold the gauges & have vacuum shut-off valves on each gauge. I couldn't even take a guess at the current cost of those liquid filled precision gauges.

 

Grainger has some standard vacuum gauges for under $10.00 ea & some liquid filled for under $17.00 ea. Problem is I believe the resolution is only in 1" Hg increments. For precision work you would really like the resolution at 1/2" hg so that usually requires larger gauge size & more expensive gauges.

 

In any case if using a set of vacuum gauges to set or check any engine vacuum readings be sure to (first) hook all gauges to ONE vacuum source to check that the gauges ALL read the exact same. Even a light drop or bump can cause a vacuum gauge to read in error.

 

Sorry I don't have a factory made gauge manifold set to recommend to you as those cheaper un-dampened multi gauge sets are something I have no confidence in so I don't use them.

 

[jviss]

DR,

 

Thanks so much for an excellent reply. I have been using the U-shaped tube, vinyl tubing with compressor oil in it, but I wanted something more 'universal' for all the bikes, and bit more 'sturdy,' if you know what I mean. I knew nothing about the need for viscous-damped gauges, so thanks for that. I see now that a good set of damped vacuum gauges is a big investment for a hobbyist, but I may scour eBay for them.

 

Any thoughts on building a differential, dial-readout vacuum gauge?

 

jv

 

p.s. I have fabrication capabilities, lathe, etc.

[dirtrider]

Morning JV

 

 

If you are referring to something that can be mounted on the bike & ridden around you can do that with a short U tube manometer. Once the basic TB balance is set statically using a longer U tube you can then mount a short (8"-10") U tube set-up on the bike & ride it around.

 

I have a 10" U tube that is mountable on my GPS ball mount.

 

As far as-- "Any thoughts on building a differential, dial-readout vacuum gauge?"--

Yes that should be possible. I have an old 4" diameter 400 inches of water vacuum gauge that I use for testing catalytic converter blockage. It isn't liquid dampened but seems to be pretty stable on needle movement.

The gauge has 2 inputs with one being the inside of the snail shaped bellows & the other being the outer housing (outside the bellows) with the gauge housing being totally sealed. I currently leave the outside input open to atmosphere so the gauge reads absolute. If that 2nd input was plumbed to the opposite side on a BMW boxer it would turn the gauge into a differential type inches of H2o gauge. The only thing is: it would have to be verified that the pressure differential was exactly off-setting before any precision measurements were done.

 

 

Added: If I was serious about needing more than a simple U tube for working on the BMW boxers I would look into the heating & cooling industry tools for monitoring heating/cooling air duct pressure differential.

 

There are some real quality looking magnetic mounting "dual" input inches of H2o hand held manometers available. Most read in the 120" to 200" range. Some with resolution down to a gnat's a$$ (like .01" H2o)