I have had my FULLFLIGHT a arms for about a year now and just recently adjusted the caster. I thought when i bought them they were ready to install so i never attempted to set it. Well after i started riding my friends LTR i realized my Z didnt handle nearly as well as his LTR, so i set out to find the problem. At first i thought that it was because i have a +1 forward style a arm set up. So i looked into that and found that Gust was running a similar setup, +1 up front and +2 in the back, (he ended running +1.5 on the front) but anyway i just figured that wasnt the problem. Then i thought it was my tires, but i rode a friends cannondale with bald tires on the front and it handled better than mine so i knew that wasnt the problem. So i started looking on here for some more info and found some articles on caster adjustment. there were no really detailed posts just a little info here so i asked drnez about it gave me a little info and i did some searches on google and this is the info i found. Caster is angle of the top ball joint or heim joint in relation to the bottom one. It has to be between a 4 and 5 degree angle (for MX). Here is what i did step by step to find the angel it was originially set at it and how i set it to the proper angle. STEP 1 First i took a motorcycle jack and put it under the quad to the height it is when i am sitting on it. then i removed the front shocks.
STEP 2 After i had the front shocks removed, i could then measure the angle the joints were at. I took and old straight tie rod as my straight edge, a small level and a angle finder (contractors protractor).
I took the tie rod and ran it along the inside of the top and bottom heim threads. then i took the angle finder and ran it along side the tie rod. after i had those steps done i had my friend hold the level on top of the angle finder untill it was level. All of that gave me my angle of 11 degrees.