Hic at idle w'stage 2.


8 replies to this topic
  • weskc35k

Posted October 12, 2007 - 10:13 PM

#1

I have read that a lot of people with the stage 2 have a hic stall happening.
I get the hiccup but it's idled up a bit so as not to stall.
The longer i have the stage 2 the more i think it's a lash issue with the cam.
Hot cams say to go 1.5mm(6 thou) and 2mm(8thou).Has anybody with a stage 2 tried a slightly larger gap.
I still get the hanging idle deal sometimes but i think it's the cables as i have risers on and they are at limit.
This is an R thread.

  • scalejockey

Posted October 13, 2007 - 05:29 AM

#2

I wonder if you'll need a larger pilot to compensate for the lack of vacuum at idle. (from the big cam)?? I know mine will do this if I simply run a lower octane fuel other than 92 chevron. And it has a stock cam..

  • camman

Posted October 13, 2007 - 01:08 PM

#3

Scalejockey is correct! Try increasing the pilot jet size.

  • weskc35k

Posted October 13, 2007 - 01:09 PM

#4

I've got a 70 in it and it's at 1 3/4 seems to be right,i just get this hic sometimes.

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  • scalejockey

Posted October 13, 2007 - 03:41 PM

#5

70 is a little richer. but does it have the emultion holes as large as the 68s? not sure if it would matter..

  • bork

Posted October 14, 2007 - 09:57 PM

#6

My buddy has same problem, Idles fine , then all of a sudden it stalls. He's tried a different carb & now bought a mikuni. Keep us informed if you find a cure. I thought maybe he had a slight leaky valve. The loose lash you mentioned , might do the trick.

  • weskc35k

Posted October 14, 2007 - 11:47 PM

#7

Did the Miky sort it or not.
It's either loading up at idle because the idle is too slow or the valve lash.

  • bork

Posted October 15, 2007 - 08:39 PM

#8

Did the Miky sort it or not.
It's either loading up at idle because the idle is too slow or the valve lash.


The miki ,NOT. same hic*stall.

  • Billahjack

Posted October 16, 2007 - 01:53 PM

#9

XR650R HRC Cam/side cut out panel/UNI Air Filter/Moriwaki Exhaust with S/A:

I'm running a stock carb with a 70s pilot, 182 main, Fuel screw 1.75 turns, B53E needle lowered 1 position (needle is pushed into main jet downward, E-clip actually raised on needle 1 notch to achieve this). Runs fairly good but still pretty rich at the 2500-5500ft Altitude range. I might go down to a 180 main jet.

I have read that the cables are sensitive and can cause the idle to hang high. I just leave a little slack in the throttle cable to let it close the throttle all the way.

My bike will idle about 300 rpm higher for around 5-10 seconds before it settles when I come up to stop lights.

I once tried the mikuni. I didn't like it. It was a pain in the butt to get the jets and XRsOnly did a poor job setting it up for my specific bike when I bought it. I gave up and went back to the stock carb. The mikuni had a great off-idle response but it was a smaller carb, flowed less air and reduced top end power. My bike also ran extremely hot at WOT with the XRsOnly tune-setup and caused it to overheat often on hot days. If I was to get another carb, it would be a Keihin FCR-MX type, but I am prefectly happy with the stock carb given the upgrade cost.

Did you adjust the fuel screw properly? Do you have a vacuum leak somewhere? That might affect the idle quality.

I'm not sure how valve lash affects the engine at idle unless your valves are not closing all the way.





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