|Tech Tips by Randy Pozzi|
|Tech Tip #33 Honda CH250 Front Wheel Bearing Replacement|
|My friend and I were riding in his car on the expressway. He turned slightly left with the road and I feel a vibration under my seat. As the road angles to the right and he negotiates the curve, there is no vibration. I tell him to cock the wheel slightly to the left again. The noise reappeared. “Your right front wheel bearing is going out,” I said. Several weeks later, he called me to thank me. His right front CV joint needed replacement.
It’s easy to diagnose similar front wheel bearing issues with the Honda CH 250. You don’t have to be on the expressway to do it. Travel between 20-25 mph on level road. Veer left and right in back-and-forth S-turns. With a load on the bike, any bearing issues will develop noise at the end of the turn. It will vibrate up to the handlebars as a hum then go away when you straighten the wheel. Because you lean into a turn on a scooter, the right front bearing will hum in a right turn and the left front bearing in a left turn.
Honda supplied a very good NTN 6201Z (ID 12mm, OD 32mm, W 10mm) deep groove radial bearings to both sides of the front wheel. Problem is, if you have the original bearings installed, they only are metal shielded on the outside and have exposed roller bearings on the inside. Surprisingly, the inside exposed rollers have only packed grease applied with no seal and no grease cavity to feed it a continued supply.
To service the wheel, place the scooter on its center stand and raise the front wheel off the ground. Loosen the brake adjuster and remove the brake cable from the brake arm. Disconnect the speedometer cable from the brake panel by removing the setscrew and pulling out the cable. Remove the torque link arm bolt and axle nut. Remove the axle shaft from the right side, side collar and wheel. (Manual 14-6)
The wheel has a bearing on each side and the right side has a dust cover. Carefully pry up the dust cover (you can use it again). Turn the inner race of each bearing with your finger. It should turn smoothly and quietly and not feel sloppy in the hub. Spinning each with your finger will give you the worst condition problem bearings. However, the riding load test previously discussed will identify the marginal bearing at the beginning of its problem cycle.
To remove the bearings, you will need to use a bearing puller to pull out the bearing on the left side (brake drum side) first. You use a 12mm bearing remover head affixed to a bearing remover hammer shaft. Once that bearing is out, remove the internal spacer and drive out the other bearing from the same side.
To install, drive the left bearing in squarely with a bearing driver until it’s seated. Be careful to drive it in straight. Install the spacer and drive the right bearing in until its seated. Install the dust seal.
It is possible to get a $2 bearing from China to fit in your wheel. I found one supplier selling 10 bearings for $14. You don’t want any inferior parts on the front wheel of your bike. It is recommended that you obtain a good quality wheel bearing as a replacement. Honda’s NTN 90912-GE1-003 ($13.63) radial ball bearing is very good. As I previously mentioned, it is only shielded on one side. If the NTN 6201Z comes in a internally greased dual shielded bearing, that’s best. There are also 6201Z-RS rubber shielded bearings that will also work but road shrapnel may work its way into the rubber and deteriorate it, so I advise not to use those. Other excellent bearing manufacturers include Timken and NSK. I used the NSK (#6201ZZC3, $8.65 ea.) bearings on my scooter.
It is advisable to replace both bearings as a set. Once you have removed an old bearing, never re-install it.
Randy Pozzi (8/2008)
and maintained by doug Elam