I say eqarlier that The Bike has never given me any significant mechanical trouble. In one respect that is because I recently ducked a problem and a potential dispute with the MoCo by simply replacing parts with better ones.
In model years through at least 2007 (2006 on the Dyna line), Harley used a chain driven cam in its TwinCam88 engine. The two cam chains, one connecting the crankshaft to one camshaft and the other linking the two camshafts, were kept under constant tension by two spring loaded tensioner shoes. On a high number of bikes, at somewhere around 30 to 50,000 miles, these tensioner shoes wore down to the point where the shop manual called for the replacement of the shoe and chain. On a few bikes, this wear was more accelerated. In any event, failure to replace worn shoes could lead to catastrophic and expensive failure and damage within the cam chest. It is my understanding that whereas in many cases Harley agreed to replace these shoes under extended warranties, in the absence of a warranty the MoCo was taking the position that this was a "wear item", similar to brake pads, and was the responsibility of the owner along with other similar maintenance items. The fact that inspection of these shoes is not even listed in the maintenance schedule would seem to undermine the MoCo's position.
Nevertheless, at 35,000 miles, and with the 5,000 mile NOLA trip looming, I decided I needed to address the situation. So I examined the alternatives.
1. Alternative 1 was simply replacing the worn shoes (if necessary). This was not terribly attractive since it did not really address the fundamental design issue, would probably cost around $450 or $500 in itself, and then would have to be repeated down the road. Just getting in to inspect them was a relatively major bit of labor. (@$300-$350, I figured).
2. Alternative 2 was to replace the entire cam drive system with gear driven cams, available from a variety of sources in the aftermarket. This was expensive and, more important to me, introduced an entirely new mechanism into the bike for which it was not necessarily designed in other respects. Many have done this and have been very happy. My mechanic recommended it, but would have charged between $1700 and $2,000 to do it. Almost all have reported an increase in noise from a geared cam system. Some have found, once inside, that the amount of runout in the main bearing precluded this option, a situation which could not be predetermined prior to ordering parts.
3. Alternative 3 was that proposed by Harley. In its 2007 Dynas and later other lines it introduced a redesigned cam chain system using hydraulic tensioners, different chains, different shoe material and a new and improved oil pump. For its earlier bikes, HD offered a hybrid "retrofit" package, which included the new pump and tensioners, but kept the old chain on the inside (the most problematic one). This was not a bad option, as the heart of the problem was addressed. This option ran about $550-$600 from Harley plus labor, or in the neighborhood of$1,000. I wasn't crazy about it because it left part of the old design in there.
4. Option 4 consisted of option 3 plus changing the inner chain...effectively installing the entirely post 2007 design in the bike. To do this, however, required changing out the cams themselves, which Harley did not provide as an option, but which Andrews Cams does. For a total parts cost of about $750 to $800, I elected to go this route, as seemed the more elegant solution, and to do the work myself, thus saving somewhere in the range of $500 in labor costs.
NOt that it influenced my decision, of course, but there was also the fact that as long as you had to change cams in the first place, it wouldn't cost anymore to put some "hot cams" in there. (As it turned out, I selected "warm" ones which seemed to produce a bit more torque at a good point in the power curve, but remain pretty close to stock.) While at it, following the recommendation of others, I also replaced the cam bearings and the lifters, for an additional cost of about $145. If I did it again, now having seen it all, I am not sure I would bother replacing the lifters (cost $125) with only 35,000 miles on the bike, as I could see no wear patterns. I did not subject the lifters and push rods to microscopic examination, however, so it may have been for the best.
This was High Anxiety time for this particular liberal arts major with no mechanical background to speak of. However, I was armed with a fierce determination not to embarrass myself, a neighbor who was an expert mechanic, the shop manual, the on-line narrative and pictorial of others who had done it, and several friends available by telephone who knew what they were doing, or at least convincingly said they did . One of the latter was also able to mail me a couple of indispensible tools which greatly facilitated the project.
As it turned out, I really did need to call on some help on a couple of occasions to make sure I understood the instructions correctly, and on one significant occasion --the dismantling of the exhaust -- just to accomplish the job. But the exhaust proved to be the only truly difficult part of the project, due to extreme rust (a prevalent problem here on the California coast) on one bolt which took up most of one days work. The rest, as they say, was a 'piece of cake' once you got the hang of it and was accomplished in just a few hours time spread out over a couple of days.
Here is a Slideshow of the project in action!
