Review on ALPHA MOTO 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 by Tyler Blake

So I can use them to sync, but the problem is that they show a lot less than the actual vacuum. but they are consistent and I was able to use them to sync. That being said, the lack of true readings prevents you from knowing the true state of your system to properly diagnose/jet change if necessary. So basically bullshit, but I missed my exchange/return window before I realized it was a defective tool. TLDR in my experience: It's like in the red on this timing tool, or I'm timing the wrong thing, or my manifold is leaking. I'm afraid something is wrong since I did a restore. I took my carburetors apart to check my gaskets, even added a gasket to the new gaskets, tore off my cap, rechecked the timing, my intake and exhaust valves, everything was fine. Still appears to be red due to a leak/poor timing. but I have everything set to be in sync in red. everything sounded great. So confusing and concerned I took it to the store who hooked it up to their sync and all was fine. Sync looks good. and still i had to pay 80 dollars to check