Carb sync

[mralex714]

Yesterday was my first attempt at syncing carbs, I used a 4 vacuum gauge tool. On first connecting the gauges the left 2 cylinders showed lower vacuum than the right 2. After running more they were closer. I got the left 2 done and the idle increased. I lowered the idle to 1k and went to the right side. I synced the right 2 together and the the left and right. The idle increased to 1500. If I tried to correct the idle it would die or surge between 500-1500. I tried several more times to synch them but ended up with the same idle issue. At 1500 all 4 gauges showed 10 inches. It was getting late and I gave up. Today I started the bike, it started right up with no choke and idled at a steady 1000 rpm. My question is do I have another issue and should I try to synch them again?

 

Duane

[Peder_y2k]

It's not that hard to hook up the synch tool again to confirm. You will know one way or the other, and no longer be concerned.

On my '88VR, if I have the least suspicion, I quickly remove the side covers exposing the carbs and hook up my equipment.

-Pete, in Tacoma WA USA

[Marcarl]

How do you know that all 4 gauges are reading the same. Gauges notoriously read different and you may have a bad one. Hopefully there is a way to check them against each other. I use a homemade tool with only 1 gauge,, I like it just fine.

And yes, if your sync is a long ways off, it will effect your idle. That's why it's recommended to blip the throttle regularity during the process, better too often then not enough.

What you are actually doing is adjusting the throttle linkage, so that all carbs operate as one unit. You could conceivably move the linkage in the wrong position temporarily and so misalign a part of the linkage, hence the need for working the linkage or blipping the throttle.