Morgan Carb Tune Pro

[fontanaman]

Like many here I have a Morgan Carb Tune Pro to check and adjust my throttle bodies.

Has anybody noticed the graduations on the Carb Tune are 2 cmHg are 20 mmHg.

On page 3-9 in my 2017 service manual state the difference in vacuum pressure between the throttle bodies should not exceed 10 mmHg.

The Carb Tune is not sensitive enough to measure the service manual requirements.

It is like using tape measure when a micrometer is required.

I used to be an hardware configuration auditor at Boeing. I got kind of good at this job but got tired of the job because "here comes the badass auditor" wears on ya after a while. I am sure these days it wouldn't take long for me to drive them batshit once again.

Anyway what do you think of the assertion the Carb Tune is not sensitive enough to measure the service manual requirements?

[raYzerman]

Who cares about graduations, as long as all four are equal, you're good. You should be able to...... however, there is always a bit of bounce to those steel rods, so you just do the best you can. Some have found they need to clean the thing(s) so they work up and down smoother. Have you got the restrictors installed in the hoses?

OR, are you saying you can't get all four to be the same no matter where you adjust the screws, i.e., the reference screw is fully closed and should have white paint and that cylinder will have the lowest reading... if another screw is also closed but the vacuum reading is not matching it, then we have a different issue (which we can fix easy enough).

[fontanaman]

I have the restrictors installed.

I can get all 4 close very close to equal but I question weather the tool is sensitive enough to meet to service manual requirements. The Carb Tune graduations are 20 mmHg and I bet it isn't sensitive enough to measure 10 mmHg which the FSR requires. If I was an auditor at Boeing I would have wrote this up. Of course we always checked for tool certifications.

[FJRoss]

Each of the major (2 cm or 20 mm) divisions is subdivided into five sub-divisions. Each small division representing 4 mm Hg equivalent. I certainly could interpolate accurately enough for 4 mm difference between columns, perhaps 2 mm. Assuming, of course, that the the column "bounce" isn't too great and stiction isn't an issue.

I use a four column differential manometer with the tubes filled with automatic transmission fluid (density is 0.85 g/cc) Mercury has a density of 13.6 g/cc. The ATF manometer will deflect 13.6/0.85 = 16 times more for a given difference in pressure compared to mercury sticks. Enough that I have to be careful that they are close before fully opening up the pinch clamps I have on the takeoffs on my 1 meter tubes. At least if you suck in a bit of ATF it won't hurt anything... Some people have designed them with a large enough (empty) reservoir at the top of each tube to accommodate the fluid if there is too large a pressure differential. Large air gap at the top also serves to help dampen pulses (I used restrictors and they are OK for the infrequency of use - maybe every two years).

[raYzerman]

I never had too much trouble, but my OCD would cause me to take extra time to get it as near perfect as possible. The fluctuations at times were annoying, but managable... I often wondered if I'd gotten their "stronger dampers" (restrictors) would have improved that significantly.... you could search out smaller ID restrictors or make some, or contact the Morgan people for them. Regardless, IMHO you can get within 10....

Meanwhile Billy Fitz likes to have the best toys and had purchased an electronic one, the TechMate VacuuMate AllWeather Pro. Too rich for my blood (at the time) but once I saw that in action, you'll realize it's the bees knees. As luck would have it, I stumbled upon a used one for about a third of the price. The internal lithium rechargeable battery was shot and you might destroy it if you took it apart.... It has an external power cord to hook up to 12V, so I made a cord to hook into a battery tender lead. Sold my Morgan Carbtune....

https://tecmate.com/vacuummate-allweather/

[dcarver]

Sensitivity is the smallest change in an input signal that causes the measuring device to respond.

Resolution is the number of significant digits (decimal places) to which a value is being reliably measured.

Accuracy refers to how close a measurement is to the true or accepted value.

Repeatability is the variation in successive measurements of the same variable taken under the same conditions (e.g., same observer, location, instrument, and procedure) in a short period of time.

Precision refers to the closeness of two or more measurements to each other.

Which of these impacts a carb sync? I would think Sensitivity and Repeatability.

I have two Morgan 4 channel devices for carb syncing the CBX with 6 discrete carbs.

Before using the two Carbtunes for the first time, I connected all 8 channels to the same vacuum source, applied appropriate suckage to approximately match the desired vacuum level at idle for the CBX, then marked the position of each rod on all 6 channels.

When adjusting, I account for the 'error' between each of the 6 channels to ensure the final adjustment is as close the same as possible.

BTW, the CBX is MUCH more difficult to sync than an FJR.

Playing around one summer day, I syncd the 2006 FJR 'by ear' then checked with Morgan. It was very close. Good enough to go, actually. But then, being the perfectionist, tweaked them in using the instrumentation.

[FJRoss]

Sensitivity is the smallest change in an input signal that causes the measuring device to respond.

Resolution is the number of significant digits (decimal places) to which a value is being reliably measured.

Accuracy refers to how close a measurement is to the true or accepted value.

Repeatability is the variation in successive measurements of the same variable taken under the same conditions (e.g., same observer, location, instrument, and procedure) in a short period of time.

Precision refers to the closeness of two or more measurements to each other.

Which of these impacts a carb sync? I would think Sensitivity and Repeatability.

I have two Morgan 4 channel devices for carb syncing the CBX with 6 discrete carbs.

Before using the two Carbtunes for the first time, I connected all 8 channels to the same vacuum source, applied appropriate suckage to approximately match the desired vacuum level at idle for the CBX, then marked the position of each rod on all 6 channels.

When adjusting, I account for the 'error' between each of the 6 channels to ensure the final adjustment is as close the same as possible.

BTW, the CBX is MUCH more difficult to sync than an FJR.

Playing around one summer day, I syncd the 2006 FJR 'by ear' then checked with Morgan. It was very close. Good enough to go, actually. But then, being the perfectionist, tweaked them in using the instrumentation.

As a (retired) scientist (analytical chemist), I appreciate the definitions. Terms that are very often mis-used.
IMHO, the biggest issue with the Morgan system is day-to-day repeatability. I would want to check calibration each time by connecting all the inputs together (as you did). Since you are using a vacuum applied to a solid mechanical system, stiction could be a very real and variable issue. That is one reason I like a liquid-filled differential manometer. You may still have slow attainment of equilibrium due to the very necessary restrictors but in a steady state, identical restrictors aren't critical since there is no net air flow. Of course, making measurements on a running engine, you are never really at a perfect steady state. Stiction isn't an issue and sensitivity (using ATF working fluid) is very much greater than with mercury sticks or the Morgan Carb Tune. Of course, I cannot measure absolute vacuum (or air flow), just differences between the channels. I open one of them about 2/3 of a turn from lightly seated and balance all of them to that one.

[gixxerjasen]

Ride more worry less.

[dcarver]

Ride more worry less.

NO! This our dead horse and we are going to beat it into submission!

[gixxerjasen]

We have so many dead horses around here.

[fontanaman]

The question I posed remains. Does the Carb Tune have enough sensitivity given its minor graduation marks are 10 times less sensitive than Yamaha advises. Beat the horse to death.

[Geezer]

My 'seat of the pants' observations lead me to believe that the variations in the carb-tune do not make a difference in performance of the electronic fuel injected engine.

[Powerman]

Once again, I've been using the same homemade mercury manometer for maybe 40+ years.
Hotwheels track in a PVC pipe with the glass tubes glued to it. Someone dwells on the graduations, I tape a ruler on the side. Tuned some serious HP motors over the years.

Looking kind of narly, ver 2.0 is on the bench.

[dcarver]

The question I posed remains. Does the Carb Tune have enough sensitivity given its minor graduation marks are 10 times less sensitive than Yamaha advises. Beat the horse to death.

Next weekend I'll grab both of my Morgan's and take them to the Metrology Lab I manage at the nuke plant. There I can perform quantitative testing with NIST traceable standards to determine, within 3 sigma, the sensitivity value of each of the 8 channels. Not kidding

While I'm at it, I'll determine accuracy too!

Edit - this will have to be static testing. Can't replicate dynamic conditions.

[FJRoss]

The question I posed remains. Does the Carb Tune have enough sensitivity given its minor graduation marks are 10 times less sensitive than Yamaha advises. Beat the horse to death.

Next weekend I'll grab both of my Morgan's and take them to the Metrology Lab I manage at the nuke plant. There I can perform quantitative testing with NIST traceable standards to determine, within 3 sigma, the sensitivity value of each of the 8 channels. Not kidding

While I'm at it, I'll determine accuracy too!

Edit - this will have to be static testing. Can't replicate dynamic conditions.

It could turn out that they are MORE accurate under real world conditions. The vibration and pulsing might prevent (or reduce) stiction.
Do it right and use your metrology lab to do your carb balancing (or TBS) directly on the bike. Screw the Carb Tune middle man.

[Toter]

The electronic version that Yamafitter has is pretty slick.

[raYzerman]

That particular one is mine (Techmate), however, Bill does have a spanky newer one. I haven't seen anything better. I would advise not to get a Digi-Sync, they are very flaky and don't work well. A homemade manometer is another good option.

https://tecmate.com/vacuummate-allweather/

[dcarver]

Well, another (1) day off and I forgot to step and fetch it for testing.
Sorry.

[Festus]

Making sure I’m reading this right. On gen 3, dial the painted one all the way in and move the rest to synch, correct? I’ve disassembled and cleaned everything so I’m starting from scratch.

[natehawk750]

I used to be an hardware configuration auditor at Boeing. I got kind of good at this job but got tired of the job because "here comes the badass auditor" wears on ya after a while. I am sure these days it wouldn't take long for me to drive them batshit once again.

Oh... you were THAT guy...