I bought this to sync the carburetors on my 4 cylinder liter bike. I looked at the reviews and saw some that were marginal, but I decided to take a chance anyway since the majority were quite good. That was a mistake.The first thing I did was to check the screw-in orifice threaded into the inlet of each gauge. Like some other reviews stated, all four of them were loose. I tightened them. Not confidence inspiring but for the price I don't mind putting in a little work.I then tested them by connecting all the gauges to a single rubber line using plastic T fittings. I pulled 5" of vacuum on them using a vacuum gauge. The gauge readings varied by as much as 3" of vacuum between them-- again, not confidence inspiring. I took the plastic lenses off and used the slotted screws on the face of each gauge to adjust them to read correctly (there is an instruction sheet that tells you how to do this).I then increased the vacuum to 10" and the gauges were off again. The error was worse at 15" of vacuum. I removed the vacuum gauge and saw that they didn't all go back to zero. Great.You can set these gauges to have the same reading at any single point, but they won't agree at any other point. Only one gauge agreed with the reading on my vacuum pump-- the others were off by at least 1-2" of vacuum in either direction. There's no way I could trust these readings-- I'd be trying to compensate for an offset between 4 different gauges. No thanks.To add insult to injury, one of them stopped working altogether. It stopped returning to zero and would move random amounts with vacuum applied. I couldn't believe it-- I hadn't even USED them yet, just tested them with a vacuum pump. I took the malfunctioning gauge apart and saw that the clock spring that returns the needle to zero was broken. It's hair-thin, and apparently it snapped just from the 5 minutes of use that I'd given it. That was the final straw-- the gauges went right back in the box after less than 10 minutes of evaluation. I rarely return anything on Amazon, but these are going back ASAP.This is one of many gauge sets on Amazon that appear to be identical but are sold under a zillion different names. I'm guessing that all of them will have similar QC and quality issues. They look very pretty-- the gauge faces are crisp, fit and finish is nice, and the blue powdercoat looks good-- but the gauges don't agree with one another, and I doubt they'd last very long when actually connected to an engine.Some people had good luck with these. If I'd been able to adjust the error out of them (IE if it had just been an offset error), I would've kept them. Instead, I'm returning them and will be using a homemade water manometer to set my carbs. I wanted to avoid this because a manometer can be touchy to use (and I don't feel like putting one together), but I'm not rolling the dice on another clone of these gauges.

Excelente

You get what you pay for. I had one gauge right out of the box that quit on me. I ended up buying a different set later on

Ayuda en gran medida en la puesta a punto de los carburadores

Does the job so im happy with it

I've had good experiences with this set of gauges. Everything arrived in good condition and in the correct quantities. A little bit of cardboard got stuck in the gauge's inlets, but that was easy enough to clean out.A few notes:As noted in other posts, there are small brass restrictors which are screwed into each gauge's inlet pipe. They might have loosened up through shipping, so be sure to tighten them back in using a small flat-blade screwdriver. I also added a tiny bit of removeable threadlocker to each one. If those restrictor orifices are not used, then the gauge needle will swing much wider with each pulse of vacuum. With the restrictors in place, the needle wobble is easily manageable, just know that there will be a small time delay in the gauge movement.You can calibrate the needle up or down so that each gauge reads the same. When turning the small silver adjuster head to make changes, use very small movements. The adjuster can only rotate a small amount, roughly 1/8th of a turn in either direction. Contrary to how it looks, it is not a screw head, and can't come out. If you try, it will break.The adjuster will be fairly tight, but will turn. If it's too sticky, try turning in each direction to free it up. Rotate the adjuster in the opposite direction that you want the needle to adjust. If you want the needle to move to the right (clockwise), turn the adjuster to the left (counterclockwise).

I'm giving 5 stars as it came next day and my carbs are now synced and the bike is finally working perfect. The plastic vacuum valves are pretty chintzey, but so it the price. Best $40 I've spent this year!

I got this thing in, one of my cylinders was reading 0 pressure. I went back and forth trying to figure out what was wrong with my engine for about a half hour before I had the thought to check the brass pipe fitting. It was clogged with some kind of white powder that was caked into the tube. I knocked it out with a punch, and now the thing works, but I'm leaving this as a 1 star review because not catching a clog in a pipe designed for measuring vacuum pressure through QA is insane.

Definitely have to set gauges at zero there is a screw to do itWon’t last forever but you are paying less than halfWorked on my picky Honda cb carbs

Terrible junk product, the one gauge was off straight out of the box and they didn't even work for 5 minutes before two of the four dials started spinning round and round, 0 out of 5 stars! What a piece of junk! Never buy this!

Great value

One was a little off but ....I ajastid it....Works great

I liked the price, the guages are quality. Never balanced carbs before this, but got great results on a 4 carb motorcycle. I had the job done in an hour and that's with playing with it some. At the time this was the cheapest set on Amazon but I am happy with it.