Another good $2 TwinMax substitute

[CycleRob]

I stumbled on this while surfing the NET. Besides a how-to, it has some explanations about liquid density, and how it relates to accuracy.

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

For longevity and possible future copy-n-paste, I saved the webpage to my drive.

[cricman]

As a cheap Scot bastard, I like this project. I bet you could modify the design and include a few loops at the bottom to save space and to add several more inches of oil weight. You would have to be sure that there were no air pockets in the loops, but thats probably not too difficult.

cricman

[Arbreacames]

Let me add some notes on the accuracy of manometers containing liquids of different densities. The spec for the vacuum difference between TBs on the 1150 engine is 5 milli-bar, which would correspond to a height difference of approximately 50 mm (2 inches) of water between the columns in a U-tube manometer:

0.005 bar X 760 mm Hg/1.0325 bar X 13.5 mm water/1 mm Hg = 50mm (=1.96 in)

where 1 atm = 1.0325 bar = 760 mm Hg, and the density of Hg = 13.5 g/ml.

Since 50 mm is easy to read, a water manometer has enough sensitivity to set the TB sync to specification. If using a mecury manometer, the difference in levels would only be 3.8 mm (.14 in), which would be pretty hard to see.

I switched from water to lamp oil because it bubbles less than water and it looks cooler. Also, it has a slightly lower density than water, so it is even more sensitive.

[frozennorth]

Hmmm, I don't know about using lamp oil. I use water and a little antifreeze for colour. At least if that ever get's sucked into the TB on really poorly balanced bike it's not the worst thing in the world. Would probably evaporate.

Here's a pic of my $5. manometer. Works like a charm. More sensitive than Merc Carb Stix.





Also, keep in mind that if you are using a fuel reprogrammer (chip), like the Techlusion 259, that it needs to be turned off prior to syncing the TB's otherwise your sync will be off. I learned this the hard way Hmm, so that's what the manual is for

[chris]

Let me add some notes on the accuracy of manometers containing liquids of different densities. The spec for the vacuum difference between TBs on the 1150 engine is 5 milli-bar, which would correspond to a height difference of approximately 50 mm (2 inches) of water between the columns in a U-tube manometer:

0.005 bar X 760 mm Hg/1.0325 bar X 13.5 mm water/1 mm Hg = 50mm (=1.96 in)

where 1 atm = 1.0325 bar = 760 mm Hg, and the density of Hg = 13.5 g/ml.

Since 50 mm is easy to read, a water manometer has enough sensitivity to set the TB sync to specification. If using a mecury manometer, the difference in levels would only be 3.8 mm (.14 in), which would be pretty hard to see.

I switched from water to lamp oil because it bubbles less than water and it looks cooler. Also, it has a slightly lower density than water, so it is even more sensitive.

What are the blue tubes at the top there?
AND if I read right a 50mm discrepancy using water means that they're within spec?

[MartinW]

My guess would be that they are a refinement to reduce the possibility of water/oil being sucked into the throttle body in the case of a serious imbalance.

Pretty cool idea really.

[BMWPA]

I made the first one with per the instructions and found the biggest difficulty was getting the bubbles out of the oil...much massaging. It works great easy to take on-and-off the bike and I balance the throttle bodies per the instructions per the 'Oil Head Maintenance Manual' http://www.ibmwr.org/r-tech/oilheads/R1 ... -25-02.pdf

Stephen

[Arjen]

This may be a stupid question, but if I understand this correctly there should be a 50mm difference in the two levels of fluid... which one has to be 50mm higher than the other? The left (cilinder) one or the right?

I want to be able to sync my TB myself and I like the homemademanometerthingie, but I'm no mechanic so I need to know every little detail. The general idea is to make the bike run smoother and not worse.

[riceburner]

This may be a stupid question, but if I understand this correctly there should be a 50mm difference in the two levels of fluid... which one has to be 50mm higher than the other? The left (cilinder) one or the right?

I want to be able to sync my TB myself and I like the homemademanometerthingie, but I'm no mechanic so I need to know every little detail. The general idea is to make the bike run smoother and not worse.

actually - aren't the pressures meant to be the same???

so the teo levels of fluid should be the same - not different.

that's why using lighter oil means you can get a better result because it responds better to smaller pressure differentials.

[MartinW]

I think you're spot on there Riceburner.

I am about to build mine having spent £5 ($10) on tubing alone so can't match the $1.55 all-in price of the original.

[MikeCam]

Arjen,

To be clear: maximum difference of 50mm when using water... equal levels at all settings from idle to 7500 rpm would be best.

Mine uses ATF (red) and when the levels get way off, bubbled up, too cold to flow, etc, I let it sit overnight at room temperature to "recalibrate".

CycleRob -- thanks for this. I have been busy syncing TB's since 2001 and have always tried to get equal levels at idle, 2500, 3500, 4500 with little or no variance between as I raise steady throttle. I had no idea that my ATF (90w?) permitted a less strenuous measure of precision.

Carlos -- thanks for the math. I'll let SamCam use it as a real world example of why she must learn this stuff in school!

MC

PS

I'd include pictures but they look just like the others.

[R4R&R]

A member of my local club brought his homemade one to our last techday. He had water in it and we all discussed alternatives. After sync'ing an R1150RT using the TwinMax, we hooked up the homemade one and it showed us how inaccurate the Twinmax was. Big difference, but not as portable (the five foot long board was a little hard to carry on the bike, but it was brought there on a bike!).

I almost want to sell the Twinmax and go with the homemade one.

[riceburner]

I think you're spot on there Riceburner.

I am about to build mine having spent £5 ($10) on tubing alone so can't match the $1.55 all-in price of the original.

Can I borrow it...

alternatively - where'd you get the bits from? and what (UK spec) diameter tubing is required?

[MartinW]

Riceburner. No problem. I found a bit of timber about 1.5in x.75in x approx 4ft long. Bought 5m tubing (approx 3/16 internal diameter - from Buck and Ryan in Guildford - £1/metre) and I already have more cable ties than you can reasonably shake a stick at.

I haven't drilled the timber and fitted the tube yet but you're welcome to borrow it once it's functional alternatively, if you want to build one, feel free to ask for cable ties.

I plan to use water coloured with some antifreeze - either that or use linseed oil which I happen to have in the garage and which is lighter(?) than water.

[klrstix]

uuhhhh...

how about olive oil??

this could get kinda interesting...

or a cooking oil of some type (not sure of the "weight" of these oils...)

just curious...

[MartinW]

useful site for liquid weights and conversions

http://www.simetric.co.uk/si_liquids.htm

also, here's my paltry DIY effort - archaeologists are going to dig these up in years to come and wonder what the hell they were used for!

[riceburner]

if you're using a lighter oil, would you need more of it??

I haven't looked at the techie bits, but is there a "minimum" amount of fluid necessary?? could you do it with just a few inches? or would it not work correctly?? if not, why not??

[riceburner]

Would 3-in-1 oil be a good oil for one of these??

might pick up some tubing (for a 1.5m stick (is that a good length?)) I calculated about 8 metres of tube!!

maybe 1.5m is too long!

[MartinW]

Riceburner,

Not sure about the oil but I can tell you that my 'meter' is 1.2m in length.

The only reason for this is that's how long the piece of timber was that I found leaning against the wheelie-bin!

I used 5m of tubing which means that approx 2.4 are attached to the timber with two lengths of 1.3m each free to be attached to the throttle bodies.

(Hey, can you tell I'm a Maths Professor )

I haven't tried mine out yet as I want to do the valve adjustments first but I suspect a 6m length might have made it more manageable but anything more than that and you'll be in danger of hanging yourself with it.

As I think I mentioned in an earlier post, I am going to try water laced with antifreeze to see how I get on.

Thinking about the length of the timber, I suspect that a much shorter length would do provided the TBs are already reasonably balanced. I suppose the longer length gives a bit more margin of error but also makes the device a little less easy to handle.

[BMWPA]

When balancing the throttle bodies the 'imbalance' may be considerable and I think the length of the hose in the homemade manometer allows for some increased pressure differences between cylinders. For instance, I was balancing my brothers R1150 which had gone 15000 without service at the 12000 interval---the difference in vacuum between the two cylinders was evidenced as greater than 1 foot difference between fluid level in either side of the manometer -- so you could see if you use a lighter weight fluid than oil or a shorter tubing you could suck your manometer fluid into the cylinder.
I just bought a wooden 1 meter long ruler as the instructions recommend with clear plastic 1/4 or so inch tubing, some 2 cycle oil, and some thick wire to attach the tubing to the ruler-- piece of cake. Now LOL it does stick a little far out of my back pocket when I ride.