As I was riding up the motorway yesterday from the city I noticed that a tingling sensation, which I'd been feeling through my handlebars, was now getting serious and had turned into a gravelly growl and was felt in the seat and footpegs at almost all rpms. It had been a minor annoyance towards the end of the return leg of my recent Victoria to Queensland ride. "Oh, well" I thought, "these bikes do this sort of thing." Knowing that my TB intake sleeve rubbers, vacuum caps, ignition timing, wheel balance, spline lube, and anything else etc., were good and not too terribly recently done, I had to sort through my brain files (Windows GitH, not Mac, and at times a slow process ) to think of any other causes. The bike runs great, idles well, pulls cleanly and strongly, shifts alright (as they do), stops really well, and otherwise felt pretty good handling-wise with the newer Conti radials and wider wheels.



For luggage carrying I had only my hard topbox out the back but sitting up high and weighted down with relatively heavy gear. I thought that might have had a bit to do with the wandering-over-the-road feeling coupled with the strong breezes lately. It has been very windy the past coupla days and the bike seemed to be reacting to that, but yesterday wasn't so windy and the bike continued to follow some random, imaginary line in the road.



Then it dawned on me. I indicated out of traffic, pulled in to a layby and rocked the bike onto the centre stand. Grasping the front wheel as best I could with the weight of the bike on the front end, I rocked the wheel from side to side and could feel a noticeable amount of freeplay of what felt like a coupla millimetres at the axle, exaggerated, of course. Home to the garage pronto!



This morning, a car jack and piece of flat timber under the motor and the front wheel was off the ground. Sure enough the bearings were stuffed. I unbolted the calipers, unscrewed the axle and slid it out, off went the wheel and onto the floor it was laid. Running one of the bearings round in circles with my fingertips on the right hand, non-circlip side, it was smooth and silky with no noise. But flipping the wheel over onto the other side and performing the same thing revealed the clear reason the 'bars have been so 'vibraty' and rough feeling; it had begun to feel like an engine vibe at a certain frequency and rpm. The left hand, circlip-side bearing was shagged, the inner race wobbles and sounded a bit like marbles in a tin half full of sand and pebbles.




I am not near my usual home tool supply with bearing drivers and snap ring pliers, so I improvise. A pair of needle-nose pliers and a thin, flat blade screwdriver became my weapon of choice for popping the snap ring out of its (not it's) groove and holding it away from the inner hub so it could be easily released. A 1/2" breaker bar became the bearing driver, removed with force by circular striking blows from a softblow hammer. The bearing dropped to the garage floor after a few good whacks, fairly easily. It is a 25x47x16mm, the industry number is 630052RS and it's (not its) sealed on both sides. The right hand side is a 25x47x12mm and is industry number 6005RS, not to get them mixed up.








I look it up on www.realoem.com/bmw and in Americaland at a BMW dealer it'd sell for about $70 plus the gubmint's share (give to Caesar what Caesar is due?). I ring a local seal & bearing supplier. The pleasant South Effrican-accented gentleman who answers the phone says he's got it for about $7, "Made in Japan," he says, "not China." for no apparent reason, but I get his drift. Mass production and cheap from the Sino block doesn't mean quality, yet.

I'm off to pick it up now in a borrowed car...



I'm home again and after a bit of a search around the bearing shop, the pleasant man gets it right the second time. Turns out that BMW use a seal on the sealed bearing carrying the part number 6005RS, but this is misleading. The bearing, once he saw it with his own eyes, is a wider than the 6005RS and in a few minutes he'd pulled a 630052RS from a box out the back. The inner race is marked with the proper standard number. It was actually $20, but the correct size. Still made in Japan. I'm not arguing! He has it. I need it.






Once home I whacked the new bearing into the freezer for an hour. I don't have access to a heat gun here where I am and knowing that heating up the wheel's hub might make the bearing slide in easier, I had to use the other method. A slightly cold-shrunk bearing proved this true. Using the old bearing as a tool I drove home the new bearing, being careful to knock it in in a circular pattern, so it was not misaligned. It went in but not without some careful but decisive blows, proving that the aluminium outer race area of the wheel is in good nick and not oversize due to the potential of a bearing spinning in the soft metal and stuffing up the wheel.





Now the wheel's back on, the calipers tightened up, the axle pinch and centre bolts are snugged and then checking for spin, are tightened in sequence. The wheel spins with no perceptible drag and except for the slight rub against the brake pads, it takes a while to stop spinning. I reckon when the Contis were fitted the axle was pulled too tightly against the inner race and over the 7000+ kms I've traveled since, the bearing couldn't take the additional sideways pressure and gave up the ghost. I'd paid a technician (at a motorbike workshop that shall remain nameless) to spin balance and then slap the wheels onto the bike for me after I had to stop and take care of a parts customer's needs during work hours. I'd spooned them both onto the rims and knowing that it would be a rush he suggested he could finish the job for me. Since it was near to closing time on a busy Saturday I agreed. Anyone could have made the mistake...I guess.



The age-old adage that if you want something done right you've got to do it for yourself, still apparently stands.



After a quick test ride down the two laners and onto the Bruce Highway she is golden again. The bike tracks straight and doesn't easily follow imperfections in the typical Australian rough as guts tarmac, the vibes have disappeared except for what was always there; a slight tingle from the motor at about 4500 to 4700 RPM...



Job done. It's relaxy drinky time...

Good job you spotted that when you did, eh?

Don't get me started on the subject of Chinese bearings. I learned that one the hard way! When you buy good ones, as my friends father used to tell us when we were young, "It's only dear the day you buy it". It took us a long time to understand that statement.

88KE

A coupla years ago my elder brother bought a rear-engined 175cc 'dune buggy', made in China. Within a few months his rambunctious grandkids had pranged it and worn a few essential bits out, then within the year had stacked the shagged beast into the hard-as gum trees out the back of his rural property. Could he get spare parts for it, including something as basic as a shock absorber? Nuh, not supplied. Gotta buy a whole new buggy.

A few years back a friend bought her teenager a Sachs Madass 125cc (German-owned but made in China) as a learner bike. The Australian distributor is always out of spares and suggests they look overseas for them. Most of the catalogue is NLA (no longer available).

They sell like the proverbial hotcake 'cause they 'look' the goods and are cheap as. But don't expect longevity or parts availability.

The old man said himself a long time ago, "it only costs a bit more to go first class."

Good spot and useful to know about this. There are just so many potential sources of vibes it's a real challenge tracking down the root cause. Still, I reckon I've got a few easy checks to make - including this one before I tackle the shaft alignment, so thanks for that mate!