carburetor synch

Ok my 81 xj650 is idleing good now and I was woundering about the vaccum synch I could not find a how to forum on it if some one could enlighten me a little bit it would be much help oh I got a carb synchronizer with the four gauges

 

Line up 1 & 2, then do 3 & 4, then line up the 2 pairs with the middle screw.

 

My bike runs pretty decent, but I know my carbs need to be synced. However, I'm not even going to bother until i get the valves in spec as well as the float heights. make sure those things are dialed in before syncing and life will be good.

 

Ok cool and what about the vaccum line into the petcock how do I keep gas flowing with the vac line out and I use the same synch screws that I bench synched with right

 

Put the petcock on PRI and yes.

 

Ok I sent to synch the carbs using the gauges and the needles. Just bounce back and forth is there a way to slow them down or make them easier to read

 

You'll need to add "restrictors" in the lines. You can use small bits of plastic spray-straw wrapped in tape to make them big enough to fit tightly in the line.

 

Do the cut pieces need to be a certain length

 

nope, just all the same. Probably like 3/8"~1/2" long would do. Long enough to push the lines back on from each side and get a good seal.

 

Ok so I got tje idle down to 1500 and once u hit the throttle it dies

 

Is the bike warmed up? You have to warm them up for it to hold a low idle. Also remember to adjust idle speed during sync . I found airline restrictos for fish tank airlines to work well on the sync gauge to keep the needles from dancing everywhere . I remember my first attempts at syncing. Man I learned a lot.

 

I have small hoses would putting a piece of smaller hose in them help restrict the needle movement

 

You'll need to add "restrictors" in the lines. You can use small bits of plastic spray-straw wrapped in tape to make them big enough to fit tightly in the line.

 

I tried it and they where still the same

 

I have replaced everything in each carb except the throttle seals but I ordered some from the site so after that there should be no reason for any leaks

 

Do you have a good seal carb to insulator to intake? Thats where the most trouble occurs. IIRC the #3 is static, you tune 4 to 3 then 1&2 then 1&2 to 3&4 via the center adjuster. All 4 should be dialed in pretty close, probably get within 95% or more accuracy. I use mercury sticks, so im not sure of the gauge style. They may be more (or less) accurate. I havent messed with my XJ carbs in years, set and forget.

 

If you need a gauge to sync your carbs don't buy one but make one that worked well for me.

Go here to see one style of carb sync tool but go to their download page to see another type. http://www.yamahabikersclub.com/forum/s ... p?tid=1571

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