DAYUAN Universal Motorcycle Vacuum Carburetor Synchronizer Synchronization Balancer Carb Sync Balancing Gauge Compatible with Honda Yamaha Kawasaki Suzuki GS KZ XS CB 550 650 750 850 900 BMW

One of gauges had a mind of it's own. Once vacuum introduced, gauge decided to rotate counter clockwise x 2 rotations. Now fixed in that position = USELESS

Two gauges have a problem with cavitation right out of the box. I swapped the hoses around to make sure it wasn’t the engine. The two gauges never changed. Put on my second set of gages everything reads fine.

Went into this reading the reviews and assuming like many things that with a bit of care it would probably be alright. Carefully Loctited in metering jets, gently adjusted gauges so they were synced, then tried to use it on my good running 2014 FJR1300 motorcycle to dial in the throttle bodies as part of a normal service. Nope, it is complete and utter junk. Needles nowhere near each other and bouncing all over. Even when you switch the lines the needles don't change general area but remain wildly uncalibrated. . This thing is total garbage and sadly I didn't get a chance to test it until after the return window closed, so I am out the cost of this useless paper weight. Might be ok for some sort of steampunk cosplay, definitely of no use at all for any mechanical purpose.

For an inexpensive gauge set they worked well - I had no problems calibrating them. Delivery was on day promised.

Yamaha boat worked as advertised