Retro fitting tapered roller bearings to your XJ 650/750
By Dwayne Verhey
For tapered roller bearings, the "Parts Plus Performance Equipment" part # is SSY500. The side of the box says the fit XS500/650/650S, TX500/650/750, all XJ650 Maxim, Seca, & Midnight Maxim, All XJ750 Seca & Maxim, All XV750 Virago, XV920R/H/J, XV1000. They were CDN$75.00 (+/- US$50.00) at the Yamarobber.
(XJ550 models can also be retrofitted using the SSY125 kit.)
The larger (lower) bearing itself bears the # 30Y, and it's bearing cone is a 48KS. For the smaller (upper), the #s are 25Y and 48YS, respectively. Manufacturers stamp is MCI. Steve C. advises these are custom made sets and not available from an industrial bearing house.
(For SSY500 and SSY125 bearing dimensions click HERE)
Pick out a nice big socket (or similar) to tap the cups into the frame with. It shouldn't bind in the frame, but it should not be so small as to contact the face of the cup. Measure how far you expect each cup to go when fully seated. Have an appropriate diameter piece of pipe at hand to tap home the lower bearing over the stem, without contacting the rollers or cage.
Follow the Haynes manual to disassemble and remove the old ones. Then you get to the tricky part. The races are an interference fit -- tight. Very tight. An automotive "pickle fork" can be used to good effect here, and at the least a hacksaw will be required. Pickle forks are most often used to separate steering components on cars. They are a wedge with a slot in the centre that will fit around the stem, but not so large as to fit around the race. They have a long handle on one end that you strike with a hammer to drive the wedge in. Because they wedge two sides at once, they are far more effective than prying with a screwdriver. They are available at some rental shops, and can be purchased at automotive supply shops or automotive tool dealers. If you've got an acetylene torch with a large (+/-#20) braising tip, or even a cutting tip without using the O2 lever, heat the race, avoiding the stem. The idea here is to expand the race before the stem can heat up too, so you need to apply a lot of heat fast in a concentrated area. If you do it right, the race may actually fall off. WEAR WELDING MITTS!!!
A mini die grinder or Dremel tool can be used to cut the race. Don't cut quite all the way through to avoid scoring the stem. Once you're down to the last 1/32" inch or so, you can tap a cold chisel in the cut and that will break the remaining sliver of metal. One side is probably enough that you can prise it off, but you can do both sides if it's still stubborn. A hacksaw can also be used for similar effect. The problem is you can't cut straight across without damaging the stem, you have to cut on a very oblique angle. Even then, you will probably score something. Just try to minimize the damage.
Now you don't care much about damaging the old stuff taking it off, but at $60.00 a set, I'm betting you don't want to damage the new ones.
The bearing of the upper pair (25Y) is a nice 'sliding fit' on the top of the stem at room temperature. The cups of each pair go in the frame, with the wide end facing out. IE the wide end of the upper cone (48YS) faces up, and the wide end of the lower cone (48KS) faces down. They are an 'interference fit' -- ie very tight because the OD of the cone is 0.001" or 0.002' larger than the ID of the frame. The lower bearing (30Y) goes on the stem of the lower triple clamp with the narrow end facing up, so as to mate with the cone and again, it's an interference fit.
A substantial temperature difference is advised. Chilling the stem and the cones in the freezer for at least a half hour makes them shrink slightly, so the OD temporarily becomes smaller. Likewise, heating the lower bearing in an oven enlarges the ID slightly. DO NOT HEAT the new bearings with direct flame!!! Use only a gentle, even, slow heating to avoid removing the temper of the steel. An oven temperature of 150 to 200 degrees F is plenty. Allow it to warm up thoroughly for a half hour or so.
When everything is ready, the lower bearing should slide right on the stem without excessive force -- maybe a little gentle tapping. That's where the piece of pipe comes in handy. (have it ready in advance, so you're not trying to find it while the bearing is cooling down!)
The cones will require some gentle tapping with an appropriate size socket (as it's hard to get the frame in the oven;-). Try to find one that's just slightly smaller than the frame so you do not damage the surface of the cone. I prefer a socket, but if you don't have any that large, a piece of hardwood laid flat over the cone should work. Insert the cups one at a time, tapping each one all the way home and making sure it rides in nice and square as it goes in. If, even using a socket, it starts to go crooked, make sure you correct immediately by tapping on the other side of the socket.
Don't get the parts mixed up in the heat of battle! Make sure you know in advance which cone goes where! I can't stress this enough: be methodical, organized and have all tools selected and laid out in advance. Do one thing at a time, and make sure you don't get the cones mixed up.
Using oven or welding mitts, install the lower bearing on the stem. With luck, there will be enough of a temperature difference that it will just drop into place, but have that piece of pipe handy just in case. The upper bearing is a nice sliding fit at room temperature. It's the one that compensates for wear, and must be adjusted. There are two thin nuts designed for hook spanners to engage (Carlton sells them if you can't get them locally). If you do end up removing the forks, re-install them nice and square before tightening the nuts.
Forks removed or not, DON'T snug the upper clamps down tight just yet, or you won't be able to properly adjust the bearings. Wind down the first nut until you just start to feel resistance to steering input. Work the steering back and forth a bit to distribute the grease, tightening the stem nut a bit more if required. Grab the forks from the front, and check for play in the bearings, adjusting as required to eliminate play without overtightening. When you are satisfied, install the locknut, and tighten it without moving the first nut. Then you can snug down the upper fork clamps, and re-assemble the rest.
Don't get the parts mixed up in the heat of battle! Make sure you know in advance which cone goes where! I can't stress this enough: be methodical, organized and have all tools selected and laid out in advance. Do one thing at a time, and make sure you don't get the cones mixed up.
tafn
dv
By Dwayne Verhey
For tapered roller bearings, the "Parts Plus Performance Equipment" part # is SSY500. The side of the box says the fit XS500/650/650S, TX500/650/750, all XJ650 Maxim, Seca, & Midnight Maxim, All XJ750 Seca & Maxim, All XV750 Virago, XV920R/H/J, XV1000. They were CDN$75.00 (+/- US$50.00) at the Yamarobber.
(XJ550 models can also be retrofitted using the SSY125 kit.)
The larger (lower) bearing itself bears the # 30Y, and it's bearing cone is a 48KS. For the smaller (upper), the #s are 25Y and 48YS, respectively. Manufacturers stamp is MCI. Steve C. advises these are custom made sets and not available from an industrial bearing house.
(For SSY500 and SSY125 bearing dimensions click HERE)
Pick out a nice big socket (or similar) to tap the cups into the frame with. It shouldn't bind in the frame, but it should not be so small as to contact the face of the cup. Measure how far you expect each cup to go when fully seated. Have an appropriate diameter piece of pipe at hand to tap home the lower bearing over the stem, without contacting the rollers or cage.
Follow the Haynes manual to disassemble and remove the old ones. Then you get to the tricky part. The races are an interference fit -- tight. Very tight. An automotive "pickle fork" can be used to good effect here, and at the least a hacksaw will be required. Pickle forks are most often used to separate steering components on cars. They are a wedge with a slot in the centre that will fit around the stem, but not so large as to fit around the race. They have a long handle on one end that you strike with a hammer to drive the wedge in. Because they wedge two sides at once, they are far more effective than prying with a screwdriver. They are available at some rental shops, and can be purchased at automotive supply shops or automotive tool dealers. If you've got an acetylene torch with a large (+/-#20) braising tip, or even a cutting tip without using the O2 lever, heat the race, avoiding the stem. The idea here is to expand the race before the stem can heat up too, so you need to apply a lot of heat fast in a concentrated area. If you do it right, the race may actually fall off. WEAR WELDING MITTS!!!
A mini die grinder or Dremel tool can be used to cut the race. Don't cut quite all the way through to avoid scoring the stem. Once you're down to the last 1/32" inch or so, you can tap a cold chisel in the cut and that will break the remaining sliver of metal. One side is probably enough that you can prise it off, but you can do both sides if it's still stubborn. A hacksaw can also be used for similar effect. The problem is you can't cut straight across without damaging the stem, you have to cut on a very oblique angle. Even then, you will probably score something. Just try to minimize the damage.
Now you don't care much about damaging the old stuff taking it off, but at $60.00 a set, I'm betting you don't want to damage the new ones.
The bearing of the upper pair (25Y) is a nice 'sliding fit' on the top of the stem at room temperature. The cups of each pair go in the frame, with the wide end facing out. IE the wide end of the upper cone (48YS) faces up, and the wide end of the lower cone (48KS) faces down. They are an 'interference fit' -- ie very tight because the OD of the cone is 0.001" or 0.002' larger than the ID of the frame. The lower bearing (30Y) goes on the stem of the lower triple clamp with the narrow end facing up, so as to mate with the cone and again, it's an interference fit.
A substantial temperature difference is advised. Chilling the stem and the cones in the freezer for at least a half hour makes them shrink slightly, so the OD temporarily becomes smaller. Likewise, heating the lower bearing in an oven enlarges the ID slightly. DO NOT HEAT the new bearings with direct flame!!! Use only a gentle, even, slow heating to avoid removing the temper of the steel. An oven temperature of 150 to 200 degrees F is plenty. Allow it to warm up thoroughly for a half hour or so.
When everything is ready, the lower bearing should slide right on the stem without excessive force -- maybe a little gentle tapping. That's where the piece of pipe comes in handy. (have it ready in advance, so you're not trying to find it while the bearing is cooling down!)
The cones will require some gentle tapping with an appropriate size socket (as it's hard to get the frame in the oven;-). Try to find one that's just slightly smaller than the frame so you do not damage the surface of the cone. I prefer a socket, but if you don't have any that large, a piece of hardwood laid flat over the cone should work. Insert the cups one at a time, tapping each one all the way home and making sure it rides in nice and square as it goes in. If, even using a socket, it starts to go crooked, make sure you correct immediately by tapping on the other side of the socket.
Don't get the parts mixed up in the heat of battle! Make sure you know in advance which cone goes where! I can't stress this enough: be methodical, organized and have all tools selected and laid out in advance. Do one thing at a time, and make sure you don't get the cones mixed up.
Using oven or welding mitts, install the lower bearing on the stem. With luck, there will be enough of a temperature difference that it will just drop into place, but have that piece of pipe handy just in case. The upper bearing is a nice sliding fit at room temperature. It's the one that compensates for wear, and must be adjusted. There are two thin nuts designed for hook spanners to engage (Carlton sells them if you can't get them locally). If you do end up removing the forks, re-install them nice and square before tightening the nuts.
Forks removed or not, DON'T snug the upper clamps down tight just yet, or you won't be able to properly adjust the bearings. Wind down the first nut until you just start to feel resistance to steering input. Work the steering back and forth a bit to distribute the grease, tightening the stem nut a bit more if required. Grab the forks from the front, and check for play in the bearings, adjusting as required to eliminate play without overtightening. When you are satisfied, install the locknut, and tighten it without moving the first nut. Then you can snug down the upper fork clamps, and re-assemble the rest.
Don't get the parts mixed up in the heat of battle! Make sure you know in advance which cone goes where! I can't stress this enough: be methodical, organized and have all tools selected and laid out in advance. Do one thing at a time, and make sure you don't get the cones mixed up.
tafn
dv
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