Sunday, August 22, 2010

Trials and Tribulations

Well, this adventure has been an adventure to get started. Bike problems have been plaguing me, making it expensive and troublesome.

It started with the end of the last trip--the one I did up north into Canada. I noticed when I got home that the back wheel was really filthy. Not just the regular dirt and brake dust, but a lot of black specs all over the wheel.

Initially I thought it was maybe tar or something I might have ridden through, but after cleaning it and looking at the swingarm near the final drive, I noticed a lot of oil residue at the bottom of the swingarm. Some seepage is "normal", but this seemed to be quite a bit of oil.

After cleaning it, I did a ride and, when I got home, there was fresh oil on the wheel again. So, I did a test to see if the rear wheel had any loose play from side to side. It did! There should be no play in the wheel.

The newer BMWs, in the big bikes, have a reputation for final drive failures. The final drive is the device that rotates the rear wheel. It is equivalent to the differential on a car. The drives have failed in several different ways, but in every case, it makes the bike potentially unsafe. It could break down in such a way as to allow the wheel to lock up, causing the bike to skid. Not a good thing at all.

So, I contacted my mechanic, talked with him about it, and we made the decision to replace the final drive unit. He found a used one and said he could install it for around $800. So, that's what we did about two weeks before the trip. I just didn't want to take a chance on a breakdown out in the boonies or worse.

With that done, I needed new tires on the bike. The front tire was definitely too worn to make the approximately 8,000 miles for the trip. The rear tire was fairly new, with it having been installed just before the northern trip. It had about 4,500 miles on it.

While I've gotten 12,000 miles on a rear tire, I'm trying a different manufacturer's tires, so I have no history as to how they will last for me. So, I ordered a new rear tire for the trip.

Got the tires installed with no problems (except the pocketbook, which is getting thinner by the day).

The next issue developed a day or so later, when I noticed a spot on the concrete below the bellows on the swingarm. It was definitely oil. Not a good thing, especially after spending good money to replace the final drive just two weeks ago.

So, another call to my mechanic, describing what was going on with the oil resulted in two possibilities. One is the final drive is leaking. The other is the transmission leaking. Neither is good.

After some discussion, I decided that I will drop the final drive and look backwards to the final drive to see if it is wet with oil, or whether the oil is coming from the transmission and running down the drive shaft tunnel and exiting at the bellows. When that is determined, I'll know what to do about it.

If it is the final drive leaking, I don't feel safe about taking off on the trip. The final drive holds only 6 ounces (180 ml) of oil when filled properly. One ml is approximately 20 drops, so the final drive holds around 3,600 drops of oil. I did some checking and it was dropping oil at the rate of several drops per day, sitting still. I don't know how fast it would drip when moving. But I don't believe it would go the 8,000 miles without running out of oil.

If it is the transmission leaking, I feel much better about going on the ride. The transmission holds a quart of oil, over 5 times as much as the final drive. So, there is a lot more oil available in the transmission.

While it is not easy to add oil to the transmission, it can be done by removing both fairings and taking out the plug and adding the oil. Probably 30 minutes of work. On the other hand, it is very difficult to deal with oil in the final drive. Removing the rear wheel is not hard, but you can't check to see if it has enough oil, and there is no way to know how much oil to add. So, it is just easier to deal with the transmission than the final drive.

My mechanic's advice is to "ride it" and not worry. But I'm a natural worrier, and I don't like the prospect of a breakdown on the road in the middle of nowhere. So, it's hard to listen to his advice.

Tomorrow morning I'll drop the final drive and find out where the oil is coming from. What will it be?...

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