Topic: Homemade Manometer

[ANVkevin]

I'm going to build a manometer to sync up my 77' CB750k's carbs similar to this --
 

My question is: what attachment or fitting do I need to connect the tubes to the vacuum attachment ports? Also, is the mixture screw the only adjustment made to the carb while using the manometer? Sorry, I'm new to bike carbs, so thanks for the patience. Cheers, -Kevin.

[upperlake04]

-  some ideas for the attachment ports -  http://www.sohc4.us/forums/index.php?topic=20284.0
-  there are slide height adjustment screws under the top caps of each carb. Red arrow points to the screws. #1-3-4 carbs are adjusted  to match the non-adjustable #2.

[OldSchool_IsCool]

Here is where you can buy vacuum port adapters if you don't want to make your own.

http://www.casporttouring.com/store/merchant.mvc?Screen=CTGY&Category_Code=twinmax

[ANVkevin]

Thanks for the help guys. I work at Lowes and happened to find all the parts I needed today. Hose, Peg Board, T-adaoptors, and the carb attachments for under $5. I was pretty happy with that. Just a few more questions before I get to sync'ing these puppies up. With the slide height adjustments screws, what am I looking for? The same height for every cylinder? If its turned in (I believe raising the slide) is that richening the mixture or leaning it out? My bike is kind of driving like a tractor at the moment, so hopefully after a good sync she'll be running a bit better. Thanks again for everyones help, I'm new to motorcycles and it's truly making it alot more enjoyable.

[oldbiker]

Syncing the carbs does not change the mixture. The idea is to get all four carbs passing the same volume of gas/air mixture so that all four cylinders are doing the same amount of work thus rhe engine runs smoothly.
Imagine how the engine would run if we made one cylinder in-active. That is an extreme example of unbalanced firing. If the carbs are not synced,  the effect is like a mild case of this rough running.

[MoTo-BunnY]

I'm thinking of rollin' my own manometer too . . . . though I wanted this original Hondaline set on feeBay, it ended up going for like $200+?! Looking at it though, it seems rather simple. . ..





what about trying to make something like the Hondaline setup up but with these gauges? And aren't those 'valves' on the Hondaline unit readily available at the hardware store as like natural gas or LPG valves or something?  seems like I have seen them before. .  . .





These gauges are on sale on feeBay, company direct, for only $3.30 @ ?!   It says they are accurate to "±2.5% Full Scale, ASME Grade B" and the range is 30" Hg, just like the Hondaline gauges. . .  .wouldn't these work? (NOTE: the scale is incorrect on the gauge in the picture and says so in the auction, for whatever reason - kinda weird) (feeBay link below)

NOSHOK 1.5" Dial Size 1/8" NPT 30" Hg Vacuum Gauge NIB

[upperlake04]

With the slide height adjustments screws, what am I looking for? The same height for every cylinder?

Yes, the samel height of material in manometer tubes or equal readings on a gauge is what to look for. The actual numbers don't matter, that all cylinders are drawing the same amount of air is.

[OldSchool_IsCool]

For fluid, use Automatic Transmission Fluid (ATF) as ingestion of ATF is actually beneficial to an engine (tho a bit smoky).  The length of your tubing will be a critical matter at startup.  You may find that you need to add perhaps several feet of coiled tubing.  Due to the fact that only one cylinder is pulling at any given moment, a slow running engine will make for more erratic levels, but should balance out as you rev slightly.

[OldBoy]

Yes, you can roll your own manometer, made one a while back.
The readings can be stabilized with simple made up restrictors  in the carb tubes.

More details on my site http://homepage.ntlworld.com/frank.cooper1/frameset.html under cheap carb balancer on the menu.

[donny]

at Lowes,  what is the carb adapter part # or what is it called? thread pitch? etc?

[Bodi]

I've tried this 4-way tubing setup. If anyone has ever done it successfully, I'm amazed at their patience at the least.
The cheap carb balancer described by oldboy is not actually a manometer (a true water manometer is impractical as it would be 30 feet high)... he has made a vacuum display of sorts by tightly fitting the hoses to bottles almost full of water so that when vacuum is applied to the tube it sucks out water until the bottle vacuum is equal. The height level/vacuum ratio is dependent on the amount of air in the bottle so the four can be matched fairly easily. This should work well for balancing the carbs.
The 4-tube setup is just a good way to go completely mental trying to use it.
Four gauges works nicely, you need restrictors in the vacuum tubes near the carb fittings to steady the needles enough to be useful. Check that they read the same when ganged onto one carb.
The Morgan carb-tune is a very nice piece of kit too!
The engine should be tuned up before trying the carb sync. Valve backlash set, ignition timing set, good sparkplugs, clean air filter(s).
Don't run the engine for long without a good strong cooling fan blowing on it.

[mustangcar]

thanks oldschool for that link for the adapers, iwas going to drill out some allen holed 5mm bolts to make some adapters for the vaccum on my 78k 750 carbs,,,by the way what is that lowes part#   for the  5mm carb adapters?

[OldSchool_IsCool]

No problem.  I'm glad to see they are still selling the adapters.  I built a manometer much like the one ANVkevin shows in the opening post of this thread.  I have since built a vacuum meter model.  I have yet to use it, so I'll let you know how it works once I do.

[mystic_1]

Nicely done.  I like the bracket. 

If I can make a suggestion, when syncing carbs I like to run a bungee cord across the mirror stems (if so equipped) and that's where I hang my guages.  My set is commercially made, don't know the brand off hand, but the gauges are mounted on a flat backing plate and I've actually permanently attached a bungee across the top edge for this purpose.  If you were to add a couple of screw eyes to the upper corners of your bracket then yours could be used in this same fashion.

This makes it very convenient to tune the carbs because the gauges are right there in front of you.

mystic_1

[Tower]

Did something similar....used the blister pack the gauges came in, as a holder for the gauges.  Makes a great dust cover and allowed me to attach the gauges to the backboard.  Aquarium inline valves and tubing attach to Honda nipples screwed into the carbs.



Maybe I'll add a swivel bracket and fan just below the gas tank.  Not really needed, but its something to do.

[Dave-and-his-550]

Now that my bike is running pretty strong, I'm considering making one of these myself. I followed a few of the links and this really seems like an easy one.

Does anybody else have tips or suggestions? Links to other tutorials on how to make them and what material to use?

When you use the vacuum gauges, it is air that adjusts the meter right? The other kind, with the liquid, or transmission fluid, you only have to get them all at the same height I noticed. I would think this is easier. Opinions?

Also, the tubes get plugged into where on the carbs? Drain plugs?

[dustyc]

I posted a pic somewhere Dave that shows where they connect.  It's to a screw on each intake.  It's the only screw on the side of the intake manifold.  I'll take another pic tomorrow or you might find it through searching.  Worst case, I'll post one tomorrow. 

I'm no help on where to get the adapters.  I'm actually looking for some to replace the plastic ones that came with my Carbtune II.  I know there's a link here somewhere.  Probably several. 

[MoTo-BunnY]

Here is where you can buy vacuum port adapters if you don't want to make your own.

http://www.casporttouring.com/store/merchant.mvc?Screen=CTGY&Category_Code=twinmax

I just finished my aforementioned carb balancers - yay! - and will be trying them out in the next few days. They even sport recycled Honda hardware and front fender bracket! 

HOWEVER, I will also add that as a source for obtaining the 5mm vacuum port adapters (as mentioned in above quote) California Sport Touring / casporttouring.com S-U-C-K-S !!!  Don't even bother trying to order from them unless you want to apparently wait MONTHS to receive them - IF EVER, with NO updates on your order unless you call (over and over again) as I have experienced.

I placed my f'ing order with them at the end of MAY and I am STILL waiting to get them. Of course their site said NOTHING of being out of stock nor that it would take sooooo long. They also cannot apparently use e-mail and you must call THEM to receive the endless painful updates to their delay after delay. I have had to call them once a week to find out endless bad news AND, as an extra bonus, be treated like I am annoying for even asking in the first place! W T F ?!?   First, they said the adapters would be in 'within days' - then it was 'any day now' - then it was 'by the end of next week' - and lately it has been 'we don't know what is going on - they should have been here by now (no shiite, sherlock) they must be held up in customs or something'. CUSTOMS?? then why the heck are they even advertising them for sale if they don't keep them in stock and have to get them from someone else, overseas???

I finally just bought them - at a much higher price, of course, on eBay and got them in like 3 days. . . .lol. Basically, if California Sport Touring can't give me a solid answer when I call next, like tomorrow, I am canceling my order. Hopefully, I will get my money back as I also notice now, that they have totally removed these items from their web page in their entirety - niiiiiiiice! If they were on eBay, I would sooooooo leave them a blistering negative feedback, as I haven't seen such a half-assed online seller and lame customer service in a looooooong time - if ever!!!

sorry for the rant but seriously, BUY FROM ANYONE BUT CALIFORNIA SPORT TOURING!!!      

[MoTo-BunnY]

Now that my bike is running pretty strong, I'm considering making one of these myself. I followed a few of the links and this really seems like an easy one.

Does anybody else have tips or suggestions? Links to other tutorials on how to make them and what material to use?

When you use the vacuum gauges, it is air that adjusts the meter right? The other kind, with the liquid, or transmission fluid, you only have to get them all at the same height I noticed. I would think this is easier. Opinions?

Also, the tubes get plugged into where on the carbs? Drain plugs?

You use 5mm adapters for the vacuum gauge hoses to slip onto. The adapters screw into the ports on your carb manifolds, where a screw and washer presently plug the port. (see 19 / 13)




(5mm thread adapters - buy them at http://www.carbtune.com/fuel.html (click on "Accessories" in the menu, on the left) (wish I would have bought from these peeps, in the first place. . . ***sigh*** see above rant.
..lol)

[MoTo-BunnY]

Here's another picture I took, just now, to help you better as that parts diagram is pretty weak on showing where the vacuum ports are.  (in relation to the fully assembled engine)

[Buber]

Manifold adapters DYI:
get a piece of copper pipe from old car brake system
cut it to desired lenghts (longer for inside carbs, easier to attach the PVC tubes then)
Using a thread cutter, make a thread at the end of the copper pipe (m5)
Add a rubber gasket, and a nut to each threaded end
hey presto - you're done...

[MJL]

I'm going to build a manometer to sync up my 77' CB750k's carbs similar to this --
 

My question is: what attachment or fitting do I need to connect the tubes to the vacuum attachment ports? Also, is the mixture screw the only adjustment made to the carb while using the manometer? Sorry, I'm new to bike carbs, so thanks for the patience. Cheers, -Kevin.

I wouldn't build exactly like in the pic. Once you put vacuum to one tube the level rises and the level in the other 3 will drop.  If you were to add a fifth tube and leave it uncapped and unconnected it would act as a resevoir and give more accurate readings.

[Dave-and-his-550]

This looks like an easy to make setup:

I've tried this 4-way tubing setup. If anyone has ever done it successfully, I'm amazed at their patience at the least.
 
The 4-tube setup is just a good way to go completely mental trying to use it.

Four gauges works nicely, you need restrictors in the vacuum tubes near the carb fittings to steady the needles enough to be useful. Check that they read the same when ganged onto one carb.

Can anybody shed some light on what Bodi is talking about here? I'm thinking of going to Menards to see if I can get the material. I'm still undecided if I should use gauges, or liquid and tubing. Going with gauges sounds easier, and less of a mess. Whats this about a restrictor for the gauge setup?

[TwoTired]

Is $80 that much of a hardship?

http://www.jcwhitney.com/Motorcycle-Fuel-System-Tools/600014252.jcw

[Dave-and-his-550]

Is $80 that much of a hardship?

http://www.jcwhitney.com/Motorcycle-Fuel-System-Tools/600014252.jcw

Maybe, maybe not. From the photo it looks like its missing a few things, I don't know why. I will see how much individual gauges cost me, the rest of the material I can probably get for less then $20. Thanks for the link though, I might prefer to spare my time and just buy em...But then again, I'd have more fun building something to how I like it