Farmer, by checking trueness I mean use an indicator like you would use to check top dead center on a piston. Clean off the axle good where you position the indicator, Set indicator to "0", slowly turn the axle by hand. It will show you the Run Out, or amount it is bent. You should have a small percentage of allowance. In other words, if it only runs out .002" or .003" that would be very little. If it's .020" or .030" it's bent bad enough to wobble. You would be hard pressed to find any that run perfectly true.

 

My friend had a wobbling axle and he had me do the work. (400ex) Not too hard really. Pull the hubs, chain and sprockets off. Take a pipe wrench and undo the locknut and the axle will slide right out. I took the axle to a machine shop and they straightened it right out for less then $30. Actually another friend told me about this because he had had the same problem. Have drove both quads and they are as straight as ever. It would be a really good idea to buy a clymer manual. They'll tell you what to do anywhere from rebuilding the engine to changing the axle.

 

I think the 400EX is gonna be alot easier than his bike. The 400EX only has the chain drive where as his will have to come out of the rear differential. But hey I have been wrong before! LOL

 

I have never messed with any work quads so I couldn't tell you. Getting a clymer would let the secret out.