Synchronization on my '81 KZ550 ltd

Hello,

I have recently started my kz550 after close to a year not running it due to me modifying it. I finally plugged the gauges to synchronize the carbs. On cylinder 1-3-4, I have a similar reading of about 12-13 inches of mercury, but on cylinder 2 I only get about 9 inches. The thing is in the manual, they recommend having a vacuum between 19 and 24 CM of Hg witch translate to 7,5 to 9,5 INCHES of Hg. Should I then dial down the vacuum on cylinder 1-3-4 to within the range or try and move up cylinder 2 to match the other 3?

The modifications on the bike are a new 4 into 1 custom air filter i made out of a K&N filter and a 4-1 exhaust with and somewhat straight pipe muffler. I rejetted the carbs to #100 main and #37 pilot and also moved the clip from #2 to #4. The Bike runs well on idle but revs slowly in my opinion. Also It seems like i have some valves clearances to address, specially on cylinder 4.

Thank for the help!

Here's a link for the filter if you are interested... (dunno if it'll work)

Adjust your valves first. Check timing and other components, then try to dial in the carbs. If one carb doesn't have a adjusting screw, make all the others match it. If you try to set the others to the same as #2, your idle will drop. I suggest setting it to match the other three. The valve adjustment might change all that. Do that first.
Steve

Adjust the one that is different. When you adjust the idle speed accordingly, that will cause the others to change as well. They all affect each other, and the idle knob affects all of them.

But the fact that #2 is so different can mean a vacuum leak or other engine condition like Swest mentioned. You may want to start at the beginning and do a full base line tune. That starts with the compression test and valve clearance check.

If you do that, make sure to read the valve train warning in my signature.

Ok I will check the valve and the compression first, and get back to you guys.

Thank you

low vac on one can be an inlet valve problem if checking clearances and intake leaks doesn't fix it.

How did you make that intake? kinda cool! Also, got a pic of that exhaust?

It's carbon fiber fabric molded against regular house hold styrofoam. It's the first version...

As for the muffler here's a link :

www.dimecitycycles.com/vintage-cafe-race...muffler-80-2250.html

So I've tried doing the valve clearance check but I could only find the 1 4 T mark on the timing element, no 2 3T mark.... So I did the best I could but still im not sure of the measurements I took for the clearance. Any thoughts?

Pics? Check them with the cam pointing away from the lifter.
Steve