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YZ250 lower steering head bearing

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How did you guys get the lower steering head bearing off of the steering stem? I replaced the garbage stock Yamaha top bearing and race with the improved "sealed" bearing, but now my bottom bearing and race is trashed as well- and neither of them were neglected.

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A person is supposed to push the stem out. This then forces the bearing off. A real pain in the ass. I cut mine off.

Thats sort of a lie. My friend is a dentist. He cut it off for me in his office. I believe a dremel tool with a cut off wheel would be just fine.

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I dont understand, how would you push the rod out? I never had to actually take the bearing off before.

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A person is supposed to push the stem out. This then forces the bearing off.

I was afraid you were going to say this. I have a 20T press in my garage, but what concerns me is the amount of metal that will be taken off the bottom triple clamp when the steering stem is driven out. The stem is held to the triple clamp, obviously, by a pressed interference fit- but how tight is it going to be after the stem is re-installed? This is the same scenario that pressing out crankshaft main bearings sometimes entails. When the bearings are pressed out of the cases, occasionally a thousandth of an inch of crankcase material goes with it which results in a looser fitting bearing upon re-installation. I definately don't want a looser fitting steering stem afterward.

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APBT,

You have a valid point. However, there are products out there that have incredible bonding strength. I work at Caterpillar and use bearing mount or Loctite bearing retainer compound. This stuff will hold bull dozer bearings in place. A motorcyle steer stem is nothing compared to the forces of heavy equipment. Pressing parts together if done squarely and evenly will produce very little abrasive wear.

Mark

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If you cut the bearing cage and rollers off, it makes it way easier to press out the race. I use wire cutters.

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I dont understand, how would you push the rod out? I never had to actually take the bearing off before.

The stem is tapered. Pushing on the top of the stem sends it through the triple clamp. After a few mm the diameter is so small the bearing falls right off.

Putting it cack on is easy. I used a piece of pvc pipe that matched the id of the bearing.

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Not having a hydraulic press handy I did as radsdad said and first cut the bearing cage off. From there some "careful" grinding with a 4 1/2" grinder. Didn't take long and the race slid right off the stem.

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Anyone have pictures of how they did this? I messed with mine for about an hour, then drove to the Yamaha dealer where they told me they use a press and would charge me $40 bucks to do it. "Uh, OK, well not today." The manual says that you can pop it right off. Not what I found to be true.

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"The manual says that you can pop it right off. Not what I found to be true."

Actually, my manual shows a diagram of a guy using a chisel to pry the old bearing off!

I just got done pressing mine out in my garage. There is a step machined in the lower edge of the bottom triple clamp stem hole, and the stem has a narrow and small snap ring on it. The stem presses straight out the bottom of the triple clamp, and releases the steering head bearing from the stem at the same time. I pressed my stem out with the nut attached to the top of the steering stem threaded flushly even with the top surface of the stem. This helped to give more surface area to spread out the pressing load over and prevent damage to the threads and top of the stem.

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