The carbs are getting close but not there...

[drooker56]

Ok, after the reasembly of the bike the carbs were rebuilt and I attempted to sync them with a needle style vacume preasure gauge. I had to make a big pvc chamber to equalize pressure but I got them close. I switched to pod filters so I dialed the screws out to 2 1/2 like was suggested on th site. It was not running bad but not as good as I had hoped.

The main problem is my idle not returning until after 30-40 seconds. It sits around 2500-3000 and won't drop. I don't know if i have a float stuck or set too high maybe. I would love some suggestion before I tear them down again.

Yesterday I turned in the scews half a turn so they are at 2 turns and my god the difference was amazing, i was running too rich (wish i had a colortune...) It still had the idle issue but it ran like an SOB, the pull was amazing even at 80 it took seconds to hit 100mph (scary stuff). I was blown away.

I don't normally drive that way but I was feeling it out.

[tarzan]

That sounds lokie a vacuum leak.Spray carb cleaner or wd-40 or even water around the outsde of carbs and near boots and vacuum connections.If rpm changes you have a leak.
Out of sync can make it climb too.
You did adjust the idle screw underneath right?It is your main idle screw.

[drooker56]

You did adjust the idle screw underneath right?It is your main idle screw.

Underneath? I have the main in the front of the carb toward the engine but it is in the top of the carb. I looked on the schematic from Yamaha and could not find anythingunderneath. What do you mean?

[tarzan]

All the XS11's I've worked on have an idle screw under the bank of carbs between carbs 2+3 towards the front of the carbs(towards cylinders).
It adjusts curb idle.

[drooker56]

Intersting I when I will go check it out.

[fredintoon]

All the XS11's I've worked on have an idle screw under the bank of carbs between carbs 2+3 towards the front of the carbs(towards cylinders) It adjusts curb idle.

Um,
us old farts call that thing a throttle stop adjuster.

[drooker56]

OK,l I know what your talking about now. I beleive that is set properly the idle does eventually drop to a normal level and I have made sure the cable IS NOT getting hung up. If I shut the bike off and turn it right back on the idle is at its normal level as well. This is really vexing, its running stronger than ever its just this one last thing...

[Ivan]

Synching one carb at a time with a single gauge will never get a decent synch. It will get you close, but then you could usually do better with a bread tie in the throat of the carbs. Get a spirit level type setup or a gauge bank or some mercury sticks and try synching them again when you can see what all carbs are doing at once. I started with just doing a pair at a time, when i did all four at once, I was surprised at how far off it was.

Basically an out of synch carb setup will hang the idle as will a lean condition. Seeing how you were too rich at idle, I dont think that is the problem.

[drooker56]

I have a buddy at work that I believe has some sticks, I will try to borrow them and see what happens. Thanks!

[John]

Main idle adjustment screw

It is different between the 78-79 and 80-81 carbs. On the older carbs, the idle adjustment is to the top rear of the carbs, and on the bottom front on the newer models.