Winter Maintenance-Part 2: The Last Bearing Job You'll Ever Do
Dec 01 '00
Without having seen it, without even knowing who you are, I can almost guarantee three things about your bike. One, your tires are probably a little over or under inflated. Two, the water level in your battery isn't what it should be. And three, unless you have hammered them to pieces, your steering head and swingarm bearings haven't been serviced since you bought your bike.
Most manufacturers recommend servicing these bearings every year, and I'd guess maybe one rider in a hundred does. With some good reason. At best, on a dirt bike or standard, it is a messy, time consuming job. At worst there is an acre or two of plastic and all the stuff hidden underneath you have to take apart just to get to the forks and swingarm. Next to having to change fork seals, it is the worst maintenance job I can think of on a motorcycle.
But if the factories were willing to add another buck or two to the price of your bike you'd never have to go through the hassle of tearing everything apart. Fortunately, on many bikes you can add a couple of steps this time and turn it into a five minute job your kid could do.
The answer, my friends, is zerks. You have to tear everything apart because the tightwads who decide these things chose 50 cents in savings over including an easy way to get grease to where its needed. By installing grease zerks in the steering head and swingarm pivots you can literally turn an all day job into something that takes five minutes.
To start you'll need to take everything apart one last time. If you don't have one already, invest in a factory shop manual for your motorcycle. I've seen too many mistaken general instructions in Chilton and Hayes manuals to recommend them. And you can get back every penny you pay for a factory manual when you sell your bike.
We'll start with the steering head. Follow the instructions for tearing down the front end. When you take the steering head out of the frame, look to see if your bike came with ball bearings. Most do because they are cheap but they aren't very durable. Too many sportbike riders know they are only a couple of bad wheelies from that familiar and expensive grinding feeling when they turn the bars.
Even if you don't have a sportbike, I highly recommend replacing the ball bearings with a roller bearing kit. If you grease them once a year they will last forever. Parts Unlimited (a distributor of aftermarket motorcycle parts) offers roller bearing conversion kits for just about every motorcycle made, and the price is usually less than $30. It's a cheap insurance policy that I can't recommend enough.
If you do this you'll need to remove the old bearing races from your steering head and frame. Use a punch and a hammer to tap the races out of the frame, tapping evenly around the race until it falls out. For the race on the steering head use a chisel to get under the race and tap evenly around it until it comes loose.
Use a degreaser and towels to get all of the grease out of the steering head on the frame but don't throw the old races away yet. Use them as drivers to tap the new races into place. The tapered face of the new races means if the old race you are using to seat the new one does stick in the frame or on the shaft of the steering head you can easily get to the underside of it and tap it out. (Just remember, in the frame the tapered end points out, top and bottom, and on the steering head the tapered end will be pointing up. Getting this wrong would be expensive and embarrassing to fix. If you're not sure how it goes sit all the parts in and make sure everything will go together like it should before you seat the races.)
When you have the races seated you're ready to install the zerk so you never have to see them again. A zerk is the name for a grease nipple (shaddup ya pervs...) When you get it installed you can use a grease gun to shoot fresh grease into the steering head and through the bearings. It will literally take less than a minute including the clean up.
Installing the zerk won't take much longer. Get a pack of six automotive-sized zerks at a parts store and have the threads measured. Next, pick up a drill bit and a tap with the same thread pitch and diameter as the zerk to cut threads in the frame where you want to install the zerk. The hardware shouldn't cost more than $20 and the tap will last for years so you can use it on future bikes.
You're going to want to install two zerks on the steering head, one close to the bottom and the other at the top of the tube. If you only install one in the middle the grease will only go through the bearing that has the least resistance. With two the grease you shoot into the top has to push against all the grease in the bottom and will find its way through the upper bearings, and vice-versa.
When deciding where to position your zerks, also try to find a location you can get to without removing the fairing from your bike if it has one, or in a conspicuous spot if you are on a cruiser and want to keep them out of sight. On any bike that is going to spend time off road your first concern has to be protect them from damage.
Once you have your places picked, use a chisel-point punch to dimple the steering head where you want to drill your hole. Then drill the hole and use the tap to cut the threads. If you have never done this before you might want to ask a friend who has used a tap before to help, but its really very simple. One thing you do want to do when you are cutting the threads is to twist the tap backwards a little after every half revolution forward. This breaks away the material being cut (you might be able to hear it snap) and ensures a clean cut. When the threads are done make sure you get any metal shavings out of the tube before continuing
Then screw in the zerk. If you have an aluminum frame make sure you don't over tighten the zerk and strip the threads. Officially snug is tight enough, you don't need to torque the zerks down. If you don't want to invest in a grease gun you can pack the bearings with grease when you reassemble the front end and test the zerk system at your local garage or Jiffy Lube. When you are greasing the bearings through the zerks remember that you don't need to flush all the old grease out, when you see a little grease coming out around the top and bottom you've given the bearings a fresh dose and it's all they need. Wipe away the excess and its done for another year.
Installing the zerks in the swingarm pivot uses the same steps but there are a couple of different things you need to be aware of. First, some monoshock suspension links use bushings instead of bearings. Using zerks with a bushing is a gamble that isn't worth taking. You can take the bushing to a bearing house to see fi they can match a roller bearing, but in my experience that has been a 50/50 bet.
One problem you are going to run into are burrs on the inside of the swingarm when you drill your hole. On the steering head its not a concern but here you are drilling into the bearing surface and any burrs will soon destroy the bearing you're trying to protect. There are ways to get rid of the burrs if you want to make the investment. Dremel makes an angle grinder for model hobbyists that is much smaller than the stuff you'll find at Home Depot. The head is about the size of a dentist's drill and can get into this spot to clean up the hole after you drill it. If you don't want to lay out the money for a tool you might only use once every few years, a good machine shop can do this job for $20-30.
When deciding where to place the zerks for the rear suspension the biggest concern is keeping them from being smashed by debris kicked up by the front tire, while making it accessible for service. If you find this magic combination, let me know. What I do is plug the holes with cap bolts, small bolts that take the place of zerks for applications like this. When I want to grease the swingarm I take out the bolts, screw in the zerks, give it a shot of grease and reinstall the cap bolts. It adds a step and minute or two to the operation but it's a lot easier than taking the whole thing apart.
Unless the bearings have gotten dry and damaged this isn't something that will create a difference in how your bike feels. But greasing these suspension bearing is something that needs to be done every year unless you want it to get to that point. If you install a set of zerks its a job you can do in just a few minutes-and it is one modification that will make your bike more attractive to any buyer (read: $$$) when its time to sell.
Brian Igo
Next Installment: Brake Service (January 2001)
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