Topic: DIY 5$ Carb Sync Tool

[78whiteorbs]

Alright ,was doing some research on getting a carb sync tool and came across many DIY instructions for making manometers:

http://www.r6messagenet.com/forums/r6-maintenance-technical/42890-instructions-carb-sync-tool-5-00-a.html

http://www.vfrdiscussion.com/forum/index.php/topic/16200-homemade-manometer/

http://www.powerchutes.com/manometer.asp

http://www.valkyrienorway.com/Tools.html

I am a DIY'er and enjoy making tools , and am cheap 

I am wondering which would be better the gauge type or the oil type. The oil type seems simpler and easier as there is no calibration required-

hope this might inspire some conversation and save someone a few bucks- compared to 60-100$ for what is really 4 vacuum gauges and some tubing and some fittings......  I think I can do better!

[Deltarider]

I share a 4 gauge vac set with a friend. Haven't used in a long time as I'm able to benchsync my carbs within 2 cmHg. Still I'd like to make an "oil one" just for the fun of it. I admire simple things and I'd like to check my intuition that tells me watching fluid levels is easier than flickering dials. As soon as I've thought out the dimension of the restrictors/dampeners I will start. BTW, could the thin, red straws as found on WD-40 cans work as restictors/dampeners inside the tubes?
I advise to take a generous length of tube to avoid swallowing. I would make them 3m each at least.

[78whiteorbs]

http://www.valkyrieforum.com/bbs/index.php?topic=3863.0

this guys manometer looks cool- scroll down

[ANVkevin]

I built a manometer nearly identical to the one picture in the second link. It works great! I'm very happy with them. You should know, just be alert if you go that route when syncing. If one carb is sucking harder than the others, there is nothing stopping the bike from sucking the fluid into the carbs. I just shut it down before it got to that point, no problem. Just a heads up.

[78whiteorbs]

were did you source the 5mm adapters from ?

[scunny]

for restricters I used a spare set of pilot jets. use a spare set of main jets to attach to carbs, they are 5mm screw. couldn't use the pilots to attach, mine are not the screw type.

[78whiteorbs]

Genious!

[seanbarney41]

if you don't have enough extra jets for 5mm adapters, Z1 Enterprises sells a set of four for, iirc, under $10...

[78whiteorbs]

thanks, I gotta local shop that has all 5mm Keihin jets for 1$ each! I am gonna make some tips myself

[seanbarney41]

thanks, I gotta local shop that has all 5mm Keihin jets for 1$ each! I am gonna make some tips myself

whoa...that's cheap, get me some!

[78whiteorbs]

paypal me ,what you need and it's on - I was shocked too!

[Deltarider]

for restricters I used a spare set of pilot jets

My guess is a 0.40 mm or a 0.38 mm restrictor is not dampening enough and that the hole needs to be smaller. Am I wrong?

[70CB750]

Did you know that petsmart sells plastic air valves for fish tanks?  How about those for limiters?

[78whiteorbs]

yeah, I saw a homemade vacuum gauge set up with one of those four channel units- it's so easy I cant believe I havent thought of making one before.

[seanbarney41]

paypal me ,what you need and it's on - I was shocked too!

hey thanks, but I'm all set right now

[78whiteorbs]

wow after watching a few youtube vids looks like this is a rather feasible idea. After I build mine I am gonna try a friends vacuum gauge and see how close it gets them .
There are a few different methods ....

carb sync 001
KZ550 KZ550A2 Carb sync diy
Yamaha FJ1200 Carb Sync 101609
Homemade Carb Synch Tool.mov
 

and try watching this goober without wincing in pain .....ugh Manometer (1978 honda cb750 carburetor vacuum adjustment)

and a SANDCAST Honda CB750 K0 Sandcast 11/10.MOV   though I think this was a mercury manometer(looks kinda homemade though

[78whiteorbs]

1976 HONDA CB750 K6 Carb Sync

and another CB

[78whiteorbs]

and here is mine I made tonight - Came out exceptionally well!
Gonna try it out tomorrow weather permitting-

manometer

[andrewk]

I had a homemade setup that I used for a few years.  It worked well, I could use it, but it is so much easier to use real gauges that I can just just hang on the handlebars and hook up.  Easy to tune, easy to store, no pissing around with ATF and a 3 foot tall manometer, lol.

The DIY method works great, though.  My only advice is that if you can afford a set of gauges, your life will be a lot easier when it comes to tuning carburetors.

[Deltarider]

but it is so much easier to use real gauges

Really? I don't find real gauges that easy (the dampeners in particular) and I don't even know my set gives real values (calibration!) Fluid levels never lie.

[scunny]

for restricters I used a spare set of pilot jets

My guess is a 0.40 mm or a 0.38 mm restrictor is not dampening enough and that the hole needs to be smaller. Am I wrong?

the pilots worked a treat.

I tried the aquarium tap thingy and wasn't happy with it, ended up just putting the ends of the 4 tubes in a bottle about half full of a 50/50 mix of engine oil with atf for colour, plugged the top of said bottle with plastecine and it works good.

[Dave K]

Speaking of gauges. I bought genuine Honda gauge set back in '73. It would drive me NUTS! I never could get all 4 gauges sync. exactly from a common vacuum source. They were expensive back in '73 also, something like $125. I virtually gave them away and bought the mercury carb stixs. Using a system such as these are perfect! If a person though thinks they can do it with just a pair a carb stix, they will be an alcoholic by the time they get it right. You need to do them all at the same time! I did though use the 4 carb stix model on the CBX though.

[andrewk]

but it is so much easier to use real gauges

Really? I don't find real gauges that easy (the dampeners in particular) and I don't even know my set gives real values (calibration!) Fluid levels never lie.

I suppose it could be a matter of preference, lol.  I find the dampeners super easy, and I don't feel the need to get super accurate with the vacuum readings.  I checked my gauge set to another vacuum gauge that I have (known to be good) and they didn't read quite the same, but the gauge set all read the same relative to my good gauge. 

It's true that it's not as accurate in terms of having a specific vacuum reading, but I don't see a great advantage to knowing that number, and given that I already bench sync carbs pretty carefully, It would be difficult for me to get the vacuum adjustment way out of spec.  My real goal is to have all the dials (that have been proven to be consistent to one another) read the same, and produce the strongest idle- the specific number in inches of Hg (to a certain extent) doesn't matter.

I can see how someone might find it easier to "level out" a manometer.  I just find it easier to match gauges, and I feel like I have more control over the accuracy that way.

The proverbial "mountain out of a molehill."

[Dave K]

Andrewk, if you were referring to my post, I could never get the 4 gauges to read the same from a common vacuum source. So one gauge would have a red wax pen mark with a +2 and another with a -1 on it. So every time you tried to sync. the carbs you had to be certain that you added or subtracted the numbers on the odd reading gauges. It wasn't the dampers that were a problem, it was the gauges themselves that would read a different from the others even from the same vacuum source. I agree, the vacuum is not all that interests me, it is that all read the same. If it didn't matter that they would be reading the same, I wouldn't bother to sync. the carbs. Just like when I check the timing, I use a dwell meter and a timing light. I am doing it to get it accurate.

[bollingball]

The gauges I bought have a calibration screw so you can make them all read the same most of them do.

                                                Ken

[Dave K]

That would make ALL the difference. The Honda ones at bought at that time, didn't have that feature. I have no idea if they changed to adjustable gauges, in the later gauges Honda sold as I had already moved on to the Carb Stixs.

[BobbyR]

All gauges have a calibration screw. Adjust to a single source and adjust. Attach them to the carbs get them all reading the same, you carbs are synched. Building your own may be fun, but riding is more fun.