No, you dont need to go out and weld your crank right now. It is just beter to do that because all two stroke crank will seperate over time and the more power you make the more faster it happens. You can take your jugs off and measure the amount of seperation (if any) that you have. Use the clymer manual. I have buddies that have had even thier welded cranks seperate, it just the nature of two strokes. Measure your crank seperation, if its within limits then your good, if its out of limits fix it cause it can become problems down the road.