stevesweetz Posted February 2, 2017 Share Posted February 2, 2017 I've been thinking about making one of those simple home made manometers out of tubing and connectors to do my own throttle body sync this year. I'd like to make a 4 cylinder one so a friend of mine can borrow it for his bike if needed. Will the manometer still work correctly if I just block off the unused 4th tube at the open end? Or does it need to be blocked off from the "circuit" completely at the bottom where it connects to the other tubes? ---Update--- I ended up just shelling out for a Morgan Carbtune. I decided that it's already going to be a big enough hassle to do the sync that I don't need further complication. Link to comment Share on other sites More sharing options...
stevesweetz Posted February 2, 2017 Author Share Posted February 2, 2017 Yeah in this case, I'd be making the kind where all the tubes are connected at the bottom and they're all sharing the same reservoir. I presume that having a consistent pressure in the unused tube would effectively cancel it out the equation, but I'm not a physicist. Hard to justify paying $85 for something I can make for $20 when I'll probably only be using it every 2 years. (Every 4K miles be damned, that's ridiculous.) Link to comment Share on other sites More sharing options...
otaylor38 Posted February 3, 2017 Share Posted February 3, 2017 What sort of pressure would the manometer need to go up to? Link to comment Share on other sites More sharing options...
stevesweetz Posted February 3, 2017 Author Share Posted February 3, 2017 What sort of pressure would the manometer need to go up to? You're not trying to reach a specific value, you're just trying to balance out two of the throttles with the one that has the factory setting mark on it. I don't think connecting a single manometer to the throttles on at a time and getting a measurement is reliable - you need the kind of thing you can connect to all 3 simultaneously. The kind of home made manometer I'm talking about is like this one. You're trying to equalize the pressure between the tubes connected to throttles - but I don't know what, if any, effect an unconnected tube would have. Link to comment Share on other sites More sharing options...
otaylor38 Posted February 3, 2017 Share Posted February 3, 2017 What sort of pressure would the manometer need to go up to? You're not trying to reach a specific value, you're just trying to balance out two of the throttles with the one that has the factory setting mark on it. I don't think connecting a single manometer to the throttles on at a time and getting a measurement is reliable - you need the kind of thing you can connect to all 3 simultaneously. The kind of home made manometer I'm talking about is like this one. You're trying to equalize the pressure between the tubes connected to throttles - but I don't know what, if any, effect an unconnected tube would have. Yeah i know that mate, i was just wondering what it's likely to go up to. There is reason behind my madness. I'm a Gas engineer and use manometers daily in my job. I was thinking you could stick 3 of these together and that would be job done? Only thing is, they only go up to 30mb usually. here's an example... http://www.jtmplumbing.co.uk/tools-sundries-c438/rothenberger-tools-c532/rothenberger-12-u-gauge-manometer-p19438/s21790?utm_source=google&utm_medium=cpc&utm_term=rothenberger-12-quot-plastic-u-gauge-manometer-12-quot-u-gauge-manometer-12-u-gauge-manometer-67060&utm_campaign=product%2Blisting%2Bads&gclid=CjwKEAiA8dDEBRDf19yI97eO0UsSJAAY_yCSiu1Y6QN1ADXaqZ_M04U4uI2AmMmVuh-HHF5V16LEmhoC5Gvw_wcB Link to comment Share on other sites More sharing options...
BBB Posted February 3, 2017 Share Posted February 3, 2017 Quick search of google shows readings of about 24cm Hg vacuum, which equates to about 300 millibar Red 2015 Tracer, UK spec (well, it was until I started messing with it...) Link to comment Share on other sites More sharing options...
otaylor38 Posted February 3, 2017 Share Posted February 3, 2017 Quick search of google shows readings of about 24cm Hg vacuum, which equates to about 300 millibar My ideas useless then. Apologies Link to comment Share on other sites More sharing options...
nnamssorxela Posted February 3, 2017 Share Posted February 3, 2017 Having a 4th capped tube should be no different than having more space between the lines. I would suspect that the level in that tube would drop a little until the vacuum in the tube was greater than the vacuum of the motor. I made mine with sprinkler line fittings, and I know they have miniature shut off valves that you could put between each line if you were really worried about it. Link to comment Share on other sites More sharing options...
rain Posted February 20, 2017 Share Posted February 20, 2017 Not cheap, agree. What you're describing makes sense... the trick is getting the reading tubes in small diameter so that the adjustment can be as fine as possible. Good luck, and post an update if you can. Mine felt off sync at 9,000 kms. It improved once I re-synced. Tubing diameter has no effect on resolution. The density of the liquid does, however. ATF will react more than Mercury, for instance. ATF is also pretty and red and if you forget to plug that 4th line, or leave one off, it won't hurt the engine too much when it gets sucked into the throttle body. Just lots of smoke. Small tubing can, however, make the response time very quick, so that the fluid levels bounce a lot more. One way to improve the system is to put pinch valves on the tubing, so that sudden changes in pressure differences between the branches are slowed down. It gives you time to react if things get too far off and the liquid starts to head up one branch and down to the throttle body. It also reduces the bouncing. Link to comment Share on other sites More sharing options...
Premium Member micah2074 Posted February 20, 2017 Premium Member Share Posted February 20, 2017 Here's what I use. http://www.carbtune.com Let’s go Brandon Link to comment Share on other sites More sharing options...
Premium Member micah2074 Posted February 20, 2017 Premium Member Share Posted February 20, 2017 Hard plastic. I've had it and used it a lot over the last 10 years or so. Let’s go Brandon Link to comment Share on other sites More sharing options...
nsmiller Posted February 20, 2017 Share Posted February 20, 2017 My suggestion is cough up the money for a quality CarbTune tool. You will be able to use it on all your bikes for the rest of your life and you'll get accurate results. The $ is strong against the the British Pound right now so its a good time to buy, seeing as how they come from the UK. EDIT: I meant to say CarbTune, Not Motion Pro Link to comment Share on other sites More sharing options...
Premium Member micah2074 Posted February 20, 2017 Premium Member Share Posted February 20, 2017 I've used both... I own the carbtune. Let’s go Brandon Link to comment Share on other sites More sharing options...
nsmiller Posted February 20, 2017 Share Posted February 20, 2017 I've used both... I own the carbtune.I had a typo, I meant to say the Carbtune as well. It is the best. Link to comment Share on other sites More sharing options...
nsmiller Posted February 20, 2017 Share Posted February 20, 2017 I've been thinking about making one of those simple home made manometers out of tubing and connectors to do my own throttle body sync this year. I'd like to make a 4 cylinder one so a friend of mine can borrow it for his bike if needed. Will the manometer still work correctly if I just block off the unused 4th tube at the open end? Or does it need to be blocked off from the "circuit" completely at the bottom where it connects to the other tubes? As I already said, I think you're better off buying a quality CarbTune tool, but if you're insistent on building your own... blocking off the tube would probably work, but valving the liquid off would probably work best. Place a valve in between each hose and then you can use it on everything from thumpers, v-twins, FJ09, and inline 4s. Link to comment Share on other sites More sharing options...
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