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HOME MADE MANOMETER HELP


aceaceca

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OK. I made my manometer as seen on the internet. I made it with about 3 1/2 feet of colored water in each of 1/4 inch tubing legs. It worked OK for idle balance but no way would it take any RPM to do high speed setting. The engine would suck all the water in. I am switching the fluid to ATF and extending the tubes but I still have my doubts it will be enough. I realize now why mercury is used as it has much more mass to be lifted. If one were to add restrictions in each line I suppose it would solve the problem but would it not be imperative that each restriction be identical. If you could advise me of the appropriate solution I would appreciate it.

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The ATF will definately help by slowing things down.

 

I suspect your throttle bodies are way out of sync. If you go without restricters just be ready to hit the kill switch right away. Make an adjustment to get yourself closer, and repeat the process.

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I noted my BBS's were only out 1/2 turn. You are correct in that the right bank is pulling way more than the left and it would inhale the water. The left bank water column moves only slightly when the throttle is cracked. I notice there are throttle butterfly stop screws on each throttle body. Should these be zeroed to close the butterflies completely?The cables all loosened to permit this.Then maybe the BBS's would be more out at the 1 to 1 1/2 turns I see mentioned.

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I'm making one my self. I don't know how to do links on this forum. But go to this thread in oilheads ( Throttle body sync for dummies) and it will show you what you need. I'm building one like Twinsig made. It should keep you from sucking your liquid of choice into your throttle bodies. ATF would be a good choice. I don't think it will help at high RPM though.

 

Jack

 

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A number of reasons why liquid manometers are appealing to the DIY crowd but not because it is a great way to tune.

 

Actually, you can achieve some of the benefits of dual vacuum gauges by not connecting the manometer as a balance device but as two manometers (about the same construction effort).

 

Ben

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I noted my BBS's were only out 1/2 turn. You are correct in that the right bank is pulling way more than the left and it would inhale the water. The left bank water column moves only slightly when the throttle is cracked. I notice there are throttle butterfly stop screws on each throttle body. Should these be zeroed to close the butterflies completely?The cables all loosened to permit this.Then maybe the BBS's would be more out at the 1 to 1 1/2 turns I see mentioned.

 

 

Try pulling the two BBS (big brass screws) out, clean the black yucky crud off of them- then use some injector cleaner and spray down the holes they came from, watch the black yucky stuff drool outa there.....once every thing is clean, put the BBS back in at turn and a half out- then start the TB balance.....and check the little o-rings on the BBS, a little silicone grease wiped on the rubber helps :thumbsup:

 

I prefer 2 stroke oil for the manometer, heaver and nothing bad will happen if my motor happens to digest some

 

Don J :wave:

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One of the benefits to the home made units, is when tightening the right side cable lock nut it throws my balance off by a few inches, so i compensate an equal amount the opposite direction then tighten the lock nut, and get it exact.

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Shove a couple of carb jets down there, one on each side of the tubing of the same jet orifice.

 

+1 on the 2 stroke oil. Good consistancy and burns good in a motor...harmless. ATF will not hurt anything, but 2 stroke oil is MADE to burn in a combustion chamber...makes sense.

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Thanks Mrduck. We must think alike as I have already done that part. I see now one does not mess with the throttle stops as they have paint on them and must be set at the factory. I think I need to do some cable work to get things closer. The idle balances at around 1/2 turn out so I do not know where the one and a half turns is coming from.

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Shove a couple of carb jets down there, one on each side of the tubing of the same jet orifice.

 

+1 on the 2 stroke oil. Good consistancy and burns good in a motor...harmless. ATF will not hurt anything, but 2 stroke oil is MADE to burn in a combustion chamber...makes sense.

 

Otherwise just put a loose clamp on the line to retard the flow, until you can get close to balanced.

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I have had the problem where the throttle bodies were so unbalanced that the fluid was sucked into one side. You may want to remove throttle bodies and thoroughly clean them. On mine, looking through the throttle bodies with them in idle posistion, I could see daylight around the edges of the butterfly valve but not the other. There was a lot of gook in them. After cleaning them, they looked about the same. After cleaning I still had a little difficulty with the synch and that is when I looked at the throttle stop screws. I noticed one side had been adjusted by someone in the past so I made a minor adjustment and then I was able to complete the synch. Runs pretty darn good now.

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Today I put the manometer hose on a new 6foot board with a 5 foot column of ATF in each leg. That solved the problem. No restriction was needed. It should be noted that you have to be patient while using this method as it takes time for the columns to respond and settle into their setting. I would say 30 seconds to a minute. Kind of slow response time. Mercury would definitely be a better fluid.As for adjustment, I surmised that if no throttle adjustment is allowed, each throttle plate should be at the fully closed position. After slackening both cables. I put a .003 feeler gauge between the throttle stop and the adjuster screw. I then took up the slack on the cable until the feeler gauge fell out. Adjusted the idle with the BBS's and the columns. Now the part throttle columns are very close. No further adjustments made. Good crisp throttle response and an idle of about 1250RPM. Ride and report tomorrow. BBS's are under a turn out.

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Glad you got it worked out.

One thing to note is that the BBS is for setting balance at idle.

The cable adjustment is for setting balance under load.

 

Once you get the idle to balance don't mess with the BBS when you are setting the cables, otherwise you will be going in circles trying to get it smoothed out.

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