blusmbl
Registered
I figured I wanted to sync the throttle bodies on my busa (already done it once on my 550, borrowing a friend's set of mercury sticks), but didn't want to ride to work and take the bike out. I found all these people that had built homemade manometers online, and figured it couldn't be that bad to do.
Short version, I got it to work, but it is a huge pain in the ass to use. Since you're essentially comparing inches of water (or ATF, in my case) to what used to be an inches of mercury tool, the fluid gets to travel a greater distance for a given vacuum. I made the tool about a foot too short. Once air enters one of the tubes, it's game over and you have to refill it, and bleeding the air out is a huge pain in the ass.
Tool in action:
We first hooked it up and thought it didn't work, as one was far higher than the others, but I moved the tube to a different throttle body and it followed the throttle body, not the tube. It works well when the bike is already pretty close in synch, just for fine tuning. The mercury ones are far less sensitive, as the resolution is smaller than using ATF or water with food coloring. (again, because mercury is ridiculously dense, and most oils are lighter than water).
I think I'm going to redo it with a larger piece of wood, and make the resivoir side longer by about half of the length increase of the tubes. A restrictor is mandatory, because on something like a motorcycle the intake pulses are ridiculous and they need to be dampened somewhat. You can literally watch the throttle bodies move with each pulse, against the springs. I found the restrictors and tees at a combination of auto parts stores. Each store would have one or two of the 3/16" restrictors needed.
I can't really give up now, I have $25 into this thing and want to succeed.
It should be useable if I make it longer, to prevent being able to suck one of the tubes dry. It seemed to be accurate (from a balance standpoint) when I compared the difference between ports on the vacuum gauge to the difference in height. However, it's enough of a pain to use that after I'm done, I may just going to hook four -14.7 - 10 transducers up to it, read the vacuum values in real time with a data aquisition tool, and adjust it from there. Or, I could've spent the $45 on the imported tool in the first place and not had any of these issues. But, what fun would that be???
Short version, I got it to work, but it is a huge pain in the ass to use. Since you're essentially comparing inches of water (or ATF, in my case) to what used to be an inches of mercury tool, the fluid gets to travel a greater distance for a given vacuum. I made the tool about a foot too short. Once air enters one of the tubes, it's game over and you have to refill it, and bleeding the air out is a huge pain in the ass.
Tool in action:
We first hooked it up and thought it didn't work, as one was far higher than the others, but I moved the tube to a different throttle body and it followed the throttle body, not the tube. It works well when the bike is already pretty close in synch, just for fine tuning. The mercury ones are far less sensitive, as the resolution is smaller than using ATF or water with food coloring. (again, because mercury is ridiculously dense, and most oils are lighter than water).
I think I'm going to redo it with a larger piece of wood, and make the resivoir side longer by about half of the length increase of the tubes. A restrictor is mandatory, because on something like a motorcycle the intake pulses are ridiculous and they need to be dampened somewhat. You can literally watch the throttle bodies move with each pulse, against the springs. I found the restrictors and tees at a combination of auto parts stores. Each store would have one or two of the 3/16" restrictors needed.
I can't really give up now, I have $25 into this thing and want to succeed.
It should be useable if I make it longer, to prevent being able to suck one of the tubes dry. It seemed to be accurate (from a balance standpoint) when I compared the difference between ports on the vacuum gauge to the difference in height. However, it's enough of a pain to use that after I'm done, I may just going to hook four -14.7 - 10 transducers up to it, read the vacuum values in real time with a data aquisition tool, and adjust it from there. Or, I could've spent the $45 on the imported tool in the first place and not had any of these issues. But, what fun would that be???
