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TC88 Cam Related Issues

by Preacher

The first and second problems may be reversed in the chronological order that they occurred.

The first problem was with the bolt that held the cam gear onto the camshaft (the shouldered bolt Hoppy writes of). They originally used a 1/4" bolt and a flat washer to hold the sprocket onto the gear with. It was breaking off near the head of the bolt. The cure for that problem was to use a larger diameter bolt (5/16") with a shoulder cast on it rather than a separate flat washer.

The second problem was with the keyed cam sprocket they tried to use. Rather than machine a key-way into the camshaft *and* the sprocket, they machined a key-way into the camshaft but they *cast* a "drift key" (kind of) into the cam sprocket so it was all one piece. The cast "key" was shearing off from the torsion needed to turn the cams. The Motor Company cured that problems by changing to a splined camshaft and drive sprocket (along with the new shouldered bolt).

The third problem was the rear outer cam bearing failures. On December 14, 1999 the Motor Company made a production line change to go from a ball style bearing to a roller style cam bearing. They also changed to a cam support plate that had a slightly larger hole machined in it for the outer cam bearings (reportedly because they thought the zero tolerance bearing fit squeezed the bearing helping it fail). They later changed back to their *original* cam support plate with the zero tolerance pressed in bearing (feeling that the first revision wasn't necessary after all).

The fourth problem (that Harley has never admitted to) was the soft cam issue. Camshafts with as little as 200 miles were showing a wear problem that looked like someone took a lathe to the cam lobes (I did an article on the problem for "Biker's Rag" magazine). The problem wasn't with the hardness of the cam but with the material they were making the cams out of. It was too soft. Not too long ago I was told that the Motor Company has changed the material that they use to cast their cams with now.

The fifth problem (also one that H-D has not admitted to) was/is with the cam chain tensioner shoes wearing out prematurely. I discovered that problem during my investigation into the "soft cams" problem. One of the HarleyTC88 list members discovered that if you polish the back side of your cam chain the abnormal wear on the tensioner shoes is pretty much eliminated. Harley has since changed the material that the tensioner shoes are made from AND it has been reported that the 2003 bikes have polished cam chains in them!

I don't know of any other *cam* related problems with the Twin-Cams but I know there have been some other problems (the BAS bracket recall, the Front Fender tip wiring recall, etc.).