Did tonight on a new bike. Service manual called for "throttle body sync" inspection/adjust at 600 miles, along with oil and filter...I do my own oil so I looked into throttle body sync.

Easy and cheep! Thought I'd briefly explain what I did...I suggest Google for a bike forum on your particular ride for full details. My Yamaha Bolt had online instructions and a YouTube...The DIY vacuum gauge bought at the shops are difficult to use...the ATF works great to smooth out the cycle of the engine for viewing.

Supplies:
20' of 3/16" ID tubing
one "T" fitting (drip irrigation, garden area)
Few ounces of AFT
Total cost: $6

Mount the tubing to a board with the middle of the hose at the bottom, add just enough ATF to fill it a couple of feet or so. Get the air out, let sit overnight for really clean lines. Hoses attach to the throttle body, in my case, two connections (Motion Pro makes the same board I made)...you could do a three or four cylinder bike I'm sure...This is not a new method, old school carb tweekers came up with this some time ago.

Why the "T"? Need to keep the rear hose to the MAP sensor inline as we check vacuum.

Engine warmed up, air cleaner and housing removed, hoses attached (hard to see the "T" but it's on the left side and goes to the MAP and rear throttle body).


Ready to go, lines in place, board with "gage" set up


Well look at that...break in caused a shift in vacuum...


a quick turn of the air screw on the front cylinder throttle body and everything went equal...
Better shot of board set up.


Time? 20 minutes to make the gage, 20 minutes to set up, check, adjust, and button back up.
Savings? About $125 to $180 depending on how good you treat your mechanic

Many times. After watching some friends mess around with home made stuff, I bought the motion pro gauges with mercury.

Yes I have. I also have a very nice commercially manufactured unit. It was great when I sync'ed my buddies 500 four cylinder Honda!

I knew this forum would have a bunch of DIY's for this...Hopefully we can get a few others to check it out and take the plunge.
Along with the simple stuff (oil and such) carb/throttle body sync, tire change, and valve adjusts are great DIY projects.

I built one of those for my four carb  Honda V65 Sabre.  works well

Never had the patience for that.  I would have just bought gauges.

I have the gauges...but nice writeup!!

That's pretty slick... I have gauges, though.

Ah, the mikuni 42mm slide carb is easy. No syncing required with that bike, but the Yami is a pain with 4 carbs. I have a 4 gauge set, but it takes a bit to get it tuned perfect across the bands. I have done some mods to the bike that didn't make my life any easier tuning. Header straight piped with a supertrapp on the end FZ600 carbs with bigger jets, pod air filters but I took those off and put the airbox back in and just use the K&N. Changed sprockets as well. This is on an old 1986 Yamaha Radian 600. It has a honda tank off a 2002 naked bike I found. Don't know what it is, but it looks better than the stock one and put a pair of 4 inch headlights with HID bulbs and ballasts. Looks better than that stock square headlight they came with in the 80's.
This was my first bike I bought with my own money when I turned 18. Someday I need to tear it down and paint it. It looks like shit but runs like a raped ape when tuned. Still keep it around for kicks. Let my neighbor on it who said he rides. Told him to roll the throttle slow or it will lift the front tire especially through a turn. He didn't listen and almost put it into my tree in the front yard. Its exhilarating, but I can only ride it for a week at a time before I get too comfortable on it and start riding like an ass.The Harley gets the most use now.
Cool set OP! Might work better than my guages.

I love the DIY stuff..

But with all the bikes I own, and especially with a couple of pain in the ass setups, I also run the MotionPro gauges.

But, well done

Yup everytime I open up the carbs. I have seen that homemade manometer used by many.

many many times. Reminds me i need to make a new gauge. Lost old one in a move.

that looks way cheaper and probably just as good as my mercury gauge

I haven't used it since I dialed in a KZ1000, it worked alright too, but the cost, damn the cost sucked

Motion Pro here too.  Almost did the hose and fluid routine but dealing with it after seemed like a mess. I hang the gauges off the mirrors with a bungy cord. Easy to see during. Easy to put away after.