What's the idle speed for an 80's FXR 1340cc with a carb? Mine idles at about 800 rpm hot. 500 it seems to bog down and hit extremely hard. Almost like engine is out of balance.

 

manual says 900 to 1100 i think. wouldnt let it go to much under 800, i have read it will have oiling problems and could risk engine damage. check out this thread.
https://www.hdforums.com/forum/evo-c...-hot-cold.html

 

Ok thanks. None of my paperwork says anything.

 

I shoot for 900. I have read (as mentioned) that 900-1100 is whats recommended, but with my new EV27 camshaft bumping away, I want it idling as low as safely recommended.

 

What happens on my 99 is that when it is cold and I let the idle get to slow, it will drop low enough to drop the vacuum to the VOES. That retards the timing, and lets the engine idle real slow. That is when it sounds like what you describe.

 

The out of balance Bama91 mentions is caused by the crankshaft slowing down as each cylinder comes up to compression, then accelerating when it fires, then slowing down again, etc, with crank speed going up and down during each revolution. That is not good! Keep your tickover at the recommended level of around 1,000rpm. If the tickover speed drops much lower the crank-shaft speed will fluctuate.

 

Ok, thanks guys. The evos are kinda new to me. Did some work on them back in the 90's but mainly did Sportster work.

 

They sound great when the idle is cut way back, but if you run the idle much under 1000 rpm, the engine doesn't get much oil and it actually fluctuates speed at different points of rotation. Not good for either.