I got this idea from imortlfool in the Valve Synch Thread. But, since there weren't any pictures, I decided to post my own.

Basically, a manometer measures pressure (Mano- is the Greek term for "gas" or "vapor"). Many expensive manometers (like the Motion Pro or Carbtune) allow you to measure the vacuum of each cylinder in cmHg (centimeter of mercury). Since the starter valves on the VFR VTEC are supposed to be set equal to each other, then there's no need to measure the vacuum of each cylinder. All we need to know is what the vacuum in the cylinders are, relative to the other cylinders. Or, to be more specifically, what the vacuum of each cylinder is compared to cylinder #4. This is what the homemade manometer was designed to do.


Each of the four plastic tubes are connect to the vacuum lines from each cylinder. Each cylinder will exert a force on the oil in each tube. Essentially, the cylinders are playing a game of tug-o-war. Whichever cylinder is creating the most pressure will "win" and pull the oil in it's tube higher than the other cylinders. Our goal is to balance the starter valves so each cylinder is exerting the same amount of force, and therefore getting the oil level in each tube to be the same.

I used 1/4" inner diameter, 3/8" outer diameter plastic tubing to build my manometer. Each tube is 7 feet long. The reason I made the tubes so long was if there was a leak anywhere in the manometer or with any connections, oil can get sucked up into your cylinders (not good). With long tubes, you should have ample to recognized the problem, panic, and then hit the kill switch.


Manometer.JPG

You'll also need two T-connectors and a small section of tube. This allows you to hook up all four tubes together. The best way to fill the manometer is from the bottom. With two of the tubes disconnected from the T-connectors, fill the tubes with oil (or another liquid of your choice, i.e. water). Connect to tubes to the T-connectors and turn the manometer upright. Gravity takes over and balances the oil levels in each tube.


ManometerConnector.JPG

If I remember correctly, the vacuum tubes on the VFR are 5/32" (3.5mm). So, I used some 1/4" to 5/32" adapters to connect the tubes togethers. Also, it might also be a good idea to got four 5/32" to 5/32" adaptors and some extra tubing (5/32" size). Disconnecting the vacuum tubes from the 5-way connector from in between the throttle bodies is not fun. So, to prepare for the day that I have to synch the starter valves again, I used the straight 5/32" adaptors and extra tubing to make the the vacuums lines on the bike longer. This will make it much easier in the future to hook up the manometer since the you can now pull the 5-way connector out from underneath the throttle bodies and disconnect it in the open.

Hope you you guys find this post helpful. Good luck synching those valves.
Tim

Awesome. Looks good.

Clever setup! I've also read about the 20mmHg difference method, which has been recommended by some, and is apparantly the Honda-approved method for the earlier bikes. The idea being to smooth the transition as the throttles are just cracked open. Has there been a consensus, here? Anyone tried both methods?

See the first two stickies (VTEC fuelling) here:
http://www.bikersoracle.com/vfr/forum/forumdisplay.php?f=4

If you use water in your manometer, 20mmHg = 10.7inH2O.

From what I remember reading on that forum, everyone thought it was a translation problem with the English service manual. But after getting someone in Japan to translate a Japanese VFR service manual for them, they found the manual was right and all the values should be set equal to the fourth cylinder. In any case, balancing the starter values with either of the two methods would probably be a vast improvement since most dealerships didn't synch them at all.

The first manometer I made was a disaster. I found water to too light (almost sucked water into my engine ). Motor oil seems to work very well.

I went and skimmed back through that thread, and it sounds like our interpretations agree. I bought my '02 two weeks ago with 9,700 miles, and it's probably never been synched. Getting them all as even as possible sounds like the way to go. After mine's synched, our bikes should be pretty equivalent and we could probably make a good comparison with the TCFPR mod (even swap it to your bike if you wanted to try it).

Motor oil is actually lighter than water, but more viscous (I'm sure you knew that).

Yeah, that's what I meant. I was going to use the word "fluid", but settled on "light" for some reason.

Haven't used my carbtune balancer for a long time, but I think I remember that there could be small plastic inline restrictors in the tubes, in addtion to the manifold adapters to limit the amount of vacuum in the system and maybe prevent the (in my case) mercury from getting sucked through into the cylinders.
Maybe you should add those to further avoid the suck=hydrolock china syndrome with your engine.

Beck
95 VFR

Definitely a good idea! But, I found with motor oil and 7 foot long tubes, I have still have a very comfortable safety margin. The highest the oil ever made it up in any of the tubes in my manometer was about 2 feet, but I was screwing around with starter valves screws. I was thinking about adding some valves to each tube. That way I could balance the cylinders one at a time.

(The first manometer I made had some serious design flaws. Actually, I should be taken out a back and beaten with a garden hose for thinking it would work.)

I have the Motion Pro carb tool, but I'm wondering if the inline restrictors are even necessary. I agree they're recommended to keep the fluid from entering the engine (mercury in my case too), but are they needed if you don't rev the engine past 3000 or so? Would the engine pull more vacuum on the tool if the restrictors are removed?

MFP-2241: Where did you find the 1/4" to 5/32" adaptors?

The highest vacuum is with the throttles closed, so I wouldn't worry about revving the engine. If it works at normal idle, it'll work at higher revs as well. I'm not going to be the one to tell you to pull the restrictors, though! There's no velocity through the restrictors, so there shouldn't be a drop in pressure (vacuum) through them either. I don't think it would make any difference in the function of the tool.

Actually, you will get higher than idle intake vacuum using engine braking (throttles closed, higher revs), but obviously we're doing this in neutral and the bike isn't rolling.

Thanks - Great posting, great tool! Not sure if a mammogram is what my bike needs
(really; at some point i'll look closer at this balance the air flow)

i was thinking that a loose wad of dry cotton in tubing would work as safety. When wetted, (or should i say "if" wetted) the cotton would severally restrict flow.

Went down to the local hardware store (Truevalue). They have almost everything there.

I just did the same thing, not quite as fancy with the zip ties as Tim's, but it worked great. Here's my manometer, using a total of 32 feet of 1/4" ID clear vinyl tubing, plastic T's, and some fork oil, which happens to be an aesthetic blue (stripped/brushed rims look spiffy, eh?):

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SV Sync 001 800.jpg


My local pharmacy/hardware place had the 1/4" T's, and these plastic 1/8"-1/4"-3/16" plastic hose adapters, which worked great. The total materials cost was about $18.

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SV Sync 002 800.jpg


I went ahead and pulled off all the PAIR stuff and capped the plugs on the valve covers and airbox bottom. It does feel good to remove some of the rat's nest under there.

My sync was way, way off. In fact, the vacuum in #2 was so high that I couldn't use the manometer (would've needed a lot more tubing and would have had to lift it up several feet higher). So, I scribed a mark on one of the flats of each adjuster, and screwed them all closed to start from scratch. #1 and #3 each bottomed out at about 3.5 turns, so I opened all three back up the same number. Much closer, then! The adjustment is pretty sensitive, just a couple of clicks make a big difference. Note that the adjusters are really easy to turn by hand if you pull them out while turning (I didn't have a short enough screwdriver, anyway). I got the levels all pretty close, within a centimeter of oil (probably less than 1mmHg), and they held pretty steady when revving the motor up and down a bit. The PGMFI light did flash with the MAP sensor disconnected, but it quit when I put everything back together, so I didn't reset the ECM. I also didn't have to mess with the idle during the sync, although when I was done it had dropped to about 900rpm, so I brought it back up after.

Hard to believe the bike would've been delivered that far out, I have to wonder if someone didn't screw them up earlier. I'm the third owner, so there's no way to know for sure.

The idle and low-throttle response is now much smoother, and with the Turbo City FPR the VTEC runs great. There's still just a hint of surge cruising at 4,600rpm, but you really have to be looking for it.

Awesome job David. Your manometer looks great! I'm glad everything went well. It really is amazing how much better the bike runs after synching the starter valves. I was having trouble starting my bike, but after the valve synch it starts great now.

The restrictors also help smooth out the pulsing and make it easier to read.

Couldn't help but notice the de-blinged exhaust, looks good. Could you post a couple of pictures of your wheels, I've been thinking about polishing the rims just the way you have done yours.
Thanks

I've been waiting for a chance to clean the bike up to get some more pictures, will post in another thread when I do. The wheels weren't as easy as I'd hoped (what is?), requiring several hours of sanding, and some touch-up paint. Satisfying result, though, really does a lot for the bike.

Quick Question. Is it necessary to pull out the starter valve screws while turning them? I turned one a little a heard it click. Is this normal or am i working against a lock mechanism? Any help would be appreciated.

Nope, no need to pull them out. The clicking is normal.

Thanks MFP

So does Honda not do a starter valve sync or is that the responsibility of the dealer, in which case it is most definitely guaranteed not to be done?

I've been wondering if you can simply use a vacuum guage to do this? If everything is supposed to sync off #4, then couldnt you just do one at a time ?

I was wunnering the same thing. [I'm thinking nobody knows, since the whole sync-valve thing is a bit of a mystery anyway] You'd need a sensitive, accurate vac gage, or even a single or two-tube manometer instead of the octopus.

Anyone? Anyone? Bueller?

You probably could, but it would be difficult. Since all the valves are using the same vaccum source, when you adjust one valve, it will decrease / increase the vaccum to the other valves. Much easier with the four tubes since you see the effects on the other valves when adjusting. Hope that makes sense.

Maybe you could take a reading off each valve first, then calculate the average and adjust to that? Not sure.

Yup. Bringing this topic back alive. I found these at Autozone and O'Reiley's.

Dorman Vacu-Tite! #47309

They're around $1.70 each.

I built one of these this weekend, to do the carbs on a Goldwing. It looks really nice...but the actual use was puzzleing. I thought maybe someone has an idea of why it didn't work.

On the goldwing you have to have a special adapter that screws into the intake runner, close to the head. I used a 5mm bolt that I drilled the center out of, then cut the head off. A 5mm locknut in the middle worked for screwing it in and out. I used a small piece of tubing to go from my 1/4" id tube down to the 5mm bolts.

I used power steering fluid first (it was what I had) then changed it to ATF afterwards(better color). I hooked all 4 tubes up, 1 to each cylinder, after warming the bike up a bit.

When I fired the bike up, the readings were all over the board...2 cylinders shot up, then air bubbles started forming in them and small amounts of fluid began making their way to the cylinders. I shut the bike down and thought a bit...and couldn't figure it out. I even tried connecting just 2 cylinders at a time(and connecting the other 2 together) but I couldn't get it to balance...it would just go fast to one cylinder.

The only thing I can think of is that maybe I have a leak on my homemade adapters, and thus I get more fluctuations than normal? I noticed the adapters got hot, and the tubes didn't have as tight a seal as before.

I have used a mercury one before, but on a different bike, with no troubles. I am nervous to use this one to do the starter synch if it isn't going to work right...i don't want to mess my VFR up.

Any ideas? I will post pictures, it is a clean looking setup for sure!

I think you have to put some restrictors into the tubes to reduce airflow.

You might try swapping the hoses around and see if the same cylinder pulls the AFT high into the tubes. If that is the case, it's just the carbs are REALLY far out of sync.

If you have a leak in the adapters I would think that you would have a low reading, not high. Since you are reading vaccum it should pull outside air from the lead which would show the low reading.

This is a differential manometer meaning that it responds to the difference in vacuum between the 4 cylinders. If you had 2 connections with leaks, the other 2 of the cylinders would read very high and try to suck the fluid in. You cannot connect only 2 for the same reason. Mercury manometers are absolute manometers, meaning that they respond individually to each cylinder's absolute vacuum, so a leak in 1 will not make another read too high.

Man, I thought that was a beer bong. Looks cool and nice concept.

Whew... I thought a Man-o-meter was some kind of test where you had to engage in stunts to prove your manhood. The more the more manly you are?

Great stuff, I'll be putting this tool together this weekend. Is there a full writeup on the disassembly of airbox, or is the service manual good enough? Should the tank be taken off entierly?

Regards,
Bruckner

There's no need to remove the tank completely. Just have to prop it up.

Taking the air box off the bike is pretty straight-forward. The only hard part is getting the MAP sensor unpluged underneath the airbox.

why did you go with 1/4" tubing as opposed to 5/32"? Probably was easier to fill, but can't think of much else.