Engine Clatter

[jpdetweiler]

Recently my 1994 K75 developed a loud engine clatter in a very narrow rpm range of 1200 to 1300 rpms. Above and below that range the engine is nice and quiet. The sound is coming from the back of the engine. I'm wondering if it's the alternator or something deeper in the engine. Any ideas?

 

[jdiaz]

The fins have probably broken in the cast alternator coupling to the engine. Its an inexpensive fix.

 

[jpdetweiler]

You were correct. The problem was with the Alternator but the fix is messy. Somewhere along the line, the bolt that holds the drive dog to the engine got sheared (not me, this is the first time I ever got down to the alternator) and, because of a loose assembly, I think the splines on the drive dog got damaged because there is a fair amount of rotational play on the part. I'm working on getting the remaining part of the bolt out of the engine and replacing the drive dog. If this doesn't work or I can't manage some other work around, I'm looking at having the engine torn down.

 

[jpdetweiler]

The sheared off portion of the bolt is out. I made a drill shim that fit inside the alternator drive shaft. The shim had a hole in the center that was the size of a drill for a bolt extractor. I was able to drill a hole down the center of the bolt fragment, get some liquid wrench on the bolt and let it soak overnight. and, using a #3 bolt extractor, I was able to remove the fragment. Parts are ordered. I'll let you know how it turns out.

 

[kbasa]

Sounds like you're on your way!

 

[jpdetweiler]

New parts have been installed. The splines on the old drive dog were worn. Bike is nice and quite again.