ASK THE MXPERTS: OFF TO THE RACES…BEARING RACES

Every backyard mechanic should own an aluminum punch for delicate jobs.

Dear MXA,
I want to change the top steering bearing race on my Yamaha YZ250, but it doesn’t fit into the head tube. I tried tapping it in with a hammer, but it would always cock sideways and wouldn’t go in any farther and was hard to get back out. Does it require special tools? Should I take it to a shop? I don’t want to ruin the race or the frame. What’s the secret?

The correct way to do it is with a race driver or race press kit. They have different diameter plugs that fit on the race and allow you to tap it in or press it down into the head tube. Motion Pro makes a Steering Head Race Driver that fits all the common races sizes and retails for $49.99 at www.motionpro.com. You can, however, install steering-head racers with basic tools. The first step is to put the new race in your freezer for an hour, then take a propane torch and carefully heat up the head tube (where the race goes in). The cold will shrink the top race and the heat will expand the head tube. Make sure that the head tube is clean of all grease and oil, and don’t overdo the heat. The cold race will often fall right into the head tube, but if it doesn’t go in easily, position the race in the opening and tap it gently with a hammer. We use an aluminum punch to seat the race down into the head tube.

 

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