Bolivar, Argentina 23 Jan 07
Odometer 38,752 m 62,365 km

Motoring east from Santiago, Chile to Bolivar, a distance of only 900 miles up and over the Andes and across the Argentine pampas, I thought it was time for El Viento to get another check-up. After all, I had replaced my sprocket carrier bearings now three times, twice in Bolivia and once in Chile, and had no way of knowing if the third time was really the charm.

It was a good thing I stopped.

Upon removing my jerry-rigged chain adjuster plates and inspecting the bearings, it was clear that they were about to blow again. Since it’s common for these parts to last tens of thousands of miles, it was now patently obvious that something was painfully amiss.
Chicato Mecanix
Juan (left), Maxi (center), Chicato (right) and friends with El Viento.
The decision to stop here was not by accident. I chose Bolivar because I wanted to visit my friend Juan, a fellow-motorcyclist who I had met seven weeks earlier in northern Chile while on a tour with his pal Daniel. As luck would have it, he is one of few Argentinos who ride the same bike as mine: a BMW F650GS Dakar. This was opportune because we were able to dissect his bike to understand what was wrong with mine.

Juan directed me to his friend Chicato, who by all accounts is the best mechanic in town. Immediately upon my arrival, Chicato and his assistant Maxi set to work on my problems. The chain-adjuster plates that I had temporarily fixed back in Santiago needed a more permanent solution; and the root cause of the repeated bearing failures had to be sorted out once and for all.

Upon closer inspection, the new, third set of bearings appeared stressed and near failure. The external metal spacer was beat up and ground down. We needed to find out why this kept happening over and over again.

After removing my rear wheel and all of its sundry parts, everything appeared to be in order. With years of collective experience among us, no one could see any problem. That is, until we took Juan’s bike apart to compare the two.

Mystery solved.
Between the two rear sprocket carrier bearings BMW inserts a small metal spacer that looks like a large washer. This holds the two bearings apart to maintain proper distance between the swing arms. No one saw it because all of the Japanese motorcycle manufacturers simply pack the two bearings together side-by-side. Leave it to German engineers to use a non-standard design that throws everyone for a loop.
BMW motorcycle dealers and certified mechanics are very few and far between. They rarely stock parts and are notorious for charging exorbitant prices for their service. Service, I might add, that is often of poor quality. For these reasons, if I cannot do the repair myself, I go out of my way to find small, knowledgeable shops that can do the work faster and at lower cost.

Usually this strategy works; sometimes it backfires.

Clearly, what happened is this. The original bearings wore out under heavy load and over a long period of time. This is normal wear and tear and to be expected. But when they were replaced the first time at a small shop in Sucre, Bolivia, the internal spacer was overlooked and accidentally discarded--disguised in a sticky, greasy sandwich between the two bearings. Without it, the swing arms pinched too close together, causing excessive heat and pressure on the external spacer and bearings.

Chicato and Maxi, along with Juan and a host of their buddies, pitched in to help. We repaired the chain-adjuster plates, then manufactured from scratch two new spacers for the sprocket carrier. The bearings themselves were replaced with a higher quality set. The whole job took a couple of days to complete only because the bearings had to be summoned from a nearby town. But all the while I felt as though I was being serviced by a NASCAR pit crew. These guys really cared, and it showed.

My sincere thanks go out to Juan, Chicato, Maxi and all of their pals. Not only were my persistent mechanical problems solved, I made some new friends and got to spend some time in a wonderful town where camaraderie is still revered.

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