Oh man, I'm crying!

I tried earlier this morning to sync my carbs, I used two jars with water inside, trying to get the levels to balance out. I blocked off my YICS passage with Rick's method. Everything was working fine until my idle went insane. It was idling at like 5,500! I put on the choke, it died down for a second then shot back up. I turned out the idle screw, no change. I turned in the idle screw, no change. I then disconnected everything and set the bike back up as it normally rides. Still the insane idle. I tried adjusting the idle again, I screwed it in alot and then BOOOM! A gunshot sound came from my engine. I screwed the idle screw out, and gave it a short run to see if that would fix the problem. After the short run I came back and idle was still at 5,500 so I messed with the idle screw again and I got another boom. At that point I just left the bike and drove my car to work.

The idle screw is on the backside of the carbs, and near the bottom in between carb 2 and 3 right?

Does screwing it out make the idle lower?

 

At 5,500 rpm's the Carbs MUST be drawing off the MAIN Jets.
You have done something to open the Butterflys and bring-in Main Jet Fuel and copious AIR.

The Idle Rod IS Between #-2 -&- #-3.
Screwing it Clockwise will increase the Idle.
Counter-clock brings the Idle down.

Something else was adjusted or is binding the Carb Linkages open.

If the Carbs were recently off the bike ... I'd look for the Throttle Cable Attachment Point on the Carb Linkages being stuck behind the Head.

This is an XJ "Rite of Passage"
Everybody jams that linkage if they are new to taking-off carbs.

If that's what you did ... don't pry it loose. It breaks-off easily and too much force will misalign the Carb linkages ... Bad news!

 

I think I might just have mal-adjusted the carbs so much that its causing the high idle. The carb synch tool I made wasn't working too well and I couldn't get the levels even close to balancing out. I'm just gonna go to the store today and buy a real carb sync tool, hopefully then I can get the carbs close enough to re-adjust the idle.

The carbs were rebuilt not too long ago, but I didn't put them back on, the PO did. The bike ran fine until I started messing with it.

 

HA! I just did this yesterday. I was syncing the carbs and adjusting mixture.

Turning the sync screw on carb 1, it was just a bit off from the others. As I turned the screw idle kept getting better and better, engine running faster and faster.

Problem was vacuum on carb #1 was going up, now down.

Analysis:

Butterfly on carb #1 was completely closed, any further turns was opening the other three.

Solution: Turn screws correct direction.

 

Yep, when I read your thread I was thinking throttle cable too.

If it's running up like you say then there has to be an air path which means the butterflys are open................ or perhaps the vacuum caps are all off and you adjusted the mixture to run like that!?
I've never tried that to see if it can be done! so who knows.


Lesson here, If it aint broke maybe your better off ($$$) not fixing it.

 

The bike would stall if the Vacuum Caps were all off.

It's pretty Common to get the engine revving too high during a sync.

If you start-off with a Highly-accurate, mechanical, "Bench Sync" it helps prevent run-away high-revving.

Plus ... adjusting the Sync "Out-of-order" will just get you "Climbing the ladder" trying to get them all synced-up.

You need to start with the Idle Mix capable of sustaining 1,000 to 1,300 rpm.

Then, with the engine somewhere closer to 12-hundred than above ... bring the Fly's together dragging the same amount of Air.
Once you get the Sync locked-in ... then, you can go-over the Pilot Mixers and Dial-in some Fine-tuning.