hi everyone.
i have 04 gs500f and have problem, i'll try to explain.
my bike have leak of power at low RMP, and i can't adjust the idle speed.
i have cleaned carbs but nothing changed. As i guess my bike is operating with one cylinder, and have backfire in one carb
i have no idea what it will be,
is it possible that it needs ignition timing adjustment?

PS: spark plugs and air filter is good

How many miles, and/or when was the last time you had your valves checked?  Some of those symptoms sound like valves with less than minimum clearance to me.

Also could be due to a clogged choke circuit.  There is a small fuel jet integrated into the bottom of the plastic float.  It gets clogged easily because it sits down at the bottom of the float bowl, and it's easy to miss when you are cleaning the carbs.

i checked valve clearance and intake valves was good, but exhaust halves not. exhaust was less then 3, is it possible that it is causing the problem?

Yes.  less than 3 is 100% your problem.  Adjust and report back.

thanks a lot. i live in Georgia outside of USA. there are no one who can correct this problem.
so i have to make it myself. is it necessary to me to buy shim tool?

or exists other way to remove shims

I think that you have to buy the shim tool.

You mean Georgia, USSR/CCCP?

yes and no ) now Georgia is a country and does not belongs to anyone.
can you give me ebay link witch shim tool and shims i have to buy?

While you could make a shim tool, the real one is cheap. MotionPro makes it.

http://www.motionpro.com/motorcycle/partno/08-0017/

They have many excellent tools.

intake valves were 0.3-0.8, also one exhaust valve was 0.3-0.8, and another was less then 0.3
i think that this problem is not caused by exhaust valve. i think that is problem can only be caused by intake valves.
so i think that that backfire in carbs is caused by damaged intake valve. what do you think bros

I had this happen before and it my intake valves are ok.  No more problems after adjusting my exhaust valves and fixing my carbs.  My bet is on a mixture problem due to you carbs.

You cannot get an accurate carb adjustment wihout first adjusting your valves.

Quote from: jestercinti on April 07, 2013, 06:44:35 PM
You cannot get an accurate carb adjustment wihout first adjusting your valves.

True if the valve clearances are out. It's not that the sync won't be accurate, you can sync anytime but..don't bother doing it if your going to do the valve clearance soon, because yes it will throw off the sync. Adjusting your valves is not a prerequisite to syncing or adjusting the carbs, unless the valves are out of spec.

i finally replaced my 2.72 shim with 2.65 but there is also no space between camshaft and shim. what will i do?

Go down a size or two until there reads the proper clearance.

FINALLY THE PROBLEM SOLVED. I REPLACED BOTH EXHAUST SHIMS