My KTM kickstand spring started popping off soon after I got the bike.
Bending the long end "hook" so that it was tighter around the kickstand hex bolt helped for awhile but the hooked end eventually broke off due to bending stress & fatigue. Replacement spring was lost a few days later in some whoops. Using the rubber holder to keep the kick stand up is only good as a short term fix.
After some thought... I came up with this washer mod. to fix my KTM kickstand spring problem (using the original broken spring).
1) Find a small steel washer that will barely fit over the kickstand hex bolt.
2) Put the washer in a vise and drill a small hole (~1/8") near outside edge.
3) Bend the washer out ~1/8", at the drilled end (clearance for spring hook).
4) Put straight (broken) end of KTM spring in a vise and carefully bend a small hook in it that will fit into the small hole in the washer. Note - modified spring should be about 1/2" shorter than a new (stock) spring.
5) Install washer over KTM kickstand hex bolt with the bent tab facing out.
6) Install the short end of spring on the frame mount and pull the long end down with needle nose pliers and fit the new hook into the drilled hole in the washer.
7) You may need to adjust hook angle or degree of washer bend to avoid scratching the kickstand pivot bushing and allen bolt head.
My washer mod. has been on the bike for over 1100 kilometers (35 hours riding time) and it is still working great after countless kickstand uses.