Service

SERVICE

Paul Dean

Losing your bearings

I keep having wheel-bearing problems with my '88 Suzuki GSX-R750. The bearings went out the first time at a little over 17,000 miles. I replaced both of them, but one of the new ones failed again only about 2500 miles later. I replaced that one, too, and it only lasted 2000 miles. When I went to change it, 1 found that the other bearing also was just about shot. That's four wheel bearings in only 5500 miles. I've been buying the bearings from the Suzuki dealer, and they appear to be exactly the same as the original ones. Am I doing something terribly wrong or do '88 GSXR750s have a wheel-bearing problem?

Billy Minor Sapulpa, Oklahoma

Suzukis of that year and model have no inherent wheel-bearing problems, so the cause of this constant failure lies either in your installation technique or with the spacer that fits between the w'heel bearings.

In most instances, premature bearing failures are the result of improper installation. This holds true for all kinds of bearings, not just those in a bike's wheels. The basic rule of thumb is to never, ever install a bearing by

transmitting force through the balls or rollers. If the bearing has to be installed in a recess that grasps the outer race-such as with a wheel bearing, which fits into the wheel hub-you press or tap only on the outer race, never on the inner; if the hearing has to he mounted around its inner race, always apply force to the inner race and not the outer.

If you don 't follow this simple guideline, the force of pressing or tapping the bearing into place is transmitted directly through the balls, making tiny flat spots on the balls and microscopic indentations in the races. Consequently, the balls will chatter as they roll on the races, which results in even more and bigger indentations and flat spots. Before long, the balls and races accumulate enough flat spots and indentations that the bearing spins roughly and soon fails altogether.

If you have been installing the bearings properly, their rapid failure may be caused by the wheel-bearing spacer. This is the metal tube that's designed to be a near-perfect fit between the inner races of the two wheel bearings; if the spacer has somehow gotten compressed, or if the wheel bearings have not been inserted all the way into their respective holes, the inner races will be pulled together when the axle is tightened. That causes a side loading that the bearings are not designed to withstand, and they will fail very quickly.

Sexagenarian wheelies

I just purchased a near-mint 1995 Kawasaki KLR650. Even though I'm nearly 60 years old, I still love to do wheelies. And when I do long-distance wheelies (of a block or more) on my KLR, engine oil gets into the airbox through the breather hose. I lose several ounces of oil every time, and that causes me concern about possible engine damage. Contacting Kawasaki's customer service department got me no satisfaction. I've done many wheelies over the years on Kawasakis, Hondas and Yamahas, both two-stroke and four-stroke, and I've never before had this problem. You'd think a dirtbike would be capable of handling wheelies. Any help would be appreciated.

Errol Overkamp Cedar Falls, Iowa

Normally, I wouldn't answer a question of this sort. But when a 60-yearold man asks for advice to pursue his love for wheelies, I can't refuse.

The solution is simple. Replace your KLR s stock breather hose with a long piece of neoprene tubing that has either the same inside diameter as the stocker, or even larger. Give the hose the biggest 360-degree loop you can manage between gearbox and airbox without it interfering with anything. Route the hose so it departs the gearbox in a perfectly vertical plane, then curves toward the front of the bike as it begins its full downward loop back to the airbox. This way, when your KLR is up on the rear wheel, the loop will prevent any oil that gets blown out of the transmission from entering the airbox by forcing it to run uphill. Then, when you set the front wheel back down, any oil in the hose will drain back down into the transmission.

Intercepting trouble

I recently had both cam chains and tensioners replaced to fix a top-end noise on my 40,000-mile '83 Honda VF750F. After the repair, the noise is gone, but the bike now has what 1 feel is lean carburation: The exhaust pops on trailing throttle, the engine hiccups and lurches at partial throttle, and it lopes at idle. The shop claimed this was because of the aftermarket slip-on mufflers and K&N air filter, but they were on the bike before the repair and it ran fine. The shop installed a Dynojet kit that improved things somewhat, and the bike makes great power when it's on the jazz; but it's still no fun at transition throttle and doesn't idle well. I've taken the bike back several times, and they've rechecked the cam timing and run it on the dyno, only to now claim I need new carbs. Help, please. I love this bike and don't want a new one, but I couldn't sell this one the way it runs anyway. Peter Carrier

Biddeford, Maine

Sounds as though either the carbs on your 750 Interceptor are way out of synchronization or that there is an air leak in one of the intake manifolds. There 's an easy way to find a leak of this type: With the engine warm and running, spray some WD-40 around all of the intake-manifold joints. If white smoke starts trailing from the exhaust, you 'll know that WD-40 has been sucked into the engine through an intake leak. You may have to spray the area again, little by little, to find the exact location of the leak.

If the problem proves not to be an intake leak, take your bike to a different, more competent shop and have them synchronize the carbs. Based on what you've told me, the mechanics at your current shop aren 't very sharp. □