Engine revving down

[crackerkorean]

I got my bike running this weekend and I am still ironing out some quirks.

http://ridersofvision.net/forum/index.php?topic=3099.0
There is what I have thus far.

I can get the bike to idle at 1000 to 1500 without any problems. What is it usppoed to idle at?

Also when the engine is revved it will go up to 4 or 5 k but it backs down really slowly.

Also while idling its almost harleyesque sounding. How smoothe is it supposed to be?

[MotorPlow]

If I remember correctly, 1300 RPM is normal at idle.
My bike's tach also takes it's time to return to idle all the way to the point that the tach will not even read "0" after the is shut off for about an hour.  This doesn't happen all the time, but most of the time.

[h2olawyer]

Dirty & poorly synchronized carbs will contribute to the slow return to idle.  Because the idle speed screw needs to be turned in so far, the throttle never fully closes.  It is the gunk in the carbs slowing down the mixture that causes the slow return.  There may be other contributing causes but getting those carbs clean & synched should be your top focus at this point.

MotorPlow is right - 1300RPM @ idle.  I just set mine so the needle points a little under 1500 & call it good.

H2O

[EH]

Also, check the fit of the carbs in their rubber manifolds for correct installation and make sure they are fastened tightly.

[crackerkorean]

Sounds like tomorrow night carbs are coming off and getting cleaned.
Is there a homebrew way to syc them?

[h2olawyer]

Look on Lucky's site (www.xz550.com).  There, you will find a link to Vision images & artwork - or something like that.  On that page, there is a diagram for building a differential manometer.  1/4" tubing, a yardstick, some electrical tape and some ATF.  Under $10 & they work great.  I built one a year ago & really like the precision I get with it.

You might also check to see if your throttle linkage is sticking someplace & give the cable a good lube.

H2O

[Walt_M.]

Have you checked your YICS for leaks?

[crackerkorean]

Walt  - I have internal and external leaks in the YICS so I removed it and plugged the hoses that goto it.

Will it revv slowly back to idle without a YICS?

[Walt_M.]

I guess that takes care of the YICS. Back to H2O's suggestions, clean and synch.