When it happens take by azone and have them check codes while running . Do not turn off it will reset and loose code
SOURCE: Hard starting when cold, runs rough at idle and any steady speed.
Your carburetors need to be cleaned. The pilot jets are at least partially plugged.
If you are comfortable doing this yourself, you need to remove the seats, fuel tank, and air induction system before you will be able to get the carbs out. Be carefull when removing the fuel tank, there is a wire harness that will need to be un plugged from it to remove it. The wire harness plug runs under the plastic tray under the seat. There are 3 plastic rivits that will need to be removed to get to the plug. The carbs come out as a pair, and can be tough to get back in the boots.
You need to remove the float bowls, remove the jets, and blow carb cleaner and compressed air through them all. The pilot jets are most likely the only culprit, but you might as well clean everything if your going to all the trouble. You should also blow carb cleaner and compressed air through all of the other passages while your at it. Make sure that you can see through the jets and there is no debris left in them. Make sure to clean the floats, needle valves, and float bowls as well.
Then re-assemble
This happens when the bike sits for long periods. The fuel we get now days has a very short shelf life before it goes bad. Fuel oxydizes over time, and it happens even faster in a small amount that is vented which is exactly as it is when its in the carburetors of a motorcycle. When fuel oxydizes and evaporates, it leaves a gummy mess behind. The pilot jets are the smallest passages that sit in the fuel, so they naturally plug first.
You can prevent this by keeping fuel stabilizer in your fuel when ever the bike will be sitting for long periods of time. Myself personally, when I store one for the winter, I like to leave the carbs empty.
SOURCE: won't idle steadily
Check the rubber boot that joins the carby to the engine to often have seen the hose clamps over tightened therefore creating a split in the rubber letting to much air in giving the rough idle eventually you wont be able to start it at all (have a good thorough look inside an outside of boot doesnt take much)
SOURCE: My 2007 Honda CRF100 wont idle, backfires when rpm...
sounds like its time to adjust those valves to me 0.003-0.004 on the filler gage or have done at shop.
SOURCE: my gs500f is back firing through the CARB. the
Lean mixtures burn very slowly, at times slowly enough to continue
burning through the power and exhaust stroke, causing a backfire when
the intake valve opens, and that flame gets a shot at the new mixture
charge.
In normal operation, as the engine slows, the fuel delivery from the
main circuit falls off, and the idle circuit is supposed to take over.
If the idle circuit flows insufficiently, that becomes a transition to
fuel starvation.
You can try pointing an unlit propane torch into the inlet air, and see
if you can get closer to an idle while supplying a supplementary fuel
source. You will need to do this in a way that gets propane to both carburetor inlets, maybe rigging a Y with vacuum hoses and
electrical tape...
This started with work on
the carburetors, so the fuel system would be the most suspect. That,
and the fact that it will run at higher RPM would seem to rule out fuel
delivery.
I was looking around at photos while developing this answer (needed to know whether this was a twin or a 4-cylinder), and one resource said the idle speed should be 1,200. I don't know if that's right, but maybe 1,000 RPM is too slow for this motor to keep it together. (I do doubt that, though.)
When I wrote that last sentence, I started to second guess myself,
thinking "What if the fuel shutoff(s) is/are vacuum operated, and as the
bike approaches idle there is insufficient vacuum to hold it/them
open?" But the I rejected that, because there is even less vacuum at
cranking speeds, yet the bike starts.
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