CBR Forum - Enthusiast forums for Honda CBR Owners - First Post! Bought a bike that needs help.

Hey guys!

As the title states, this is my first post, and I'm needing some help with the bike I just picked up. For reference, it's an '87 1000f.

I have utilized the Search feature of the forum already, using 'Starter' as a keyword. I came across threads illustrating the failure to start the engine due to an alternator damper, a reduction gear and also a broken starter chain. I'm not sure which one of these might be the problem I'm experiencing, so I will go forth in explaining what I have personally experienced so far:

Again, I bought the bike with known starting problems. The previous owner states that, from his own research, he found out that a "plastic gear needed to be replaced, and the bike will only start with a bump-start. Makes a grinding noise when using the electric start."

From here I decided that I would start the repair process with a known-good starter motor. I bought one in good working order and installed it.

We encountered the grinding, or rattling sound when we tried to start the bike last night; The motor does turn freely and almost fired a few times, and I'm sure it would have if we could get a few more rotations out of it. However, whatever is causing the motor to not be able to turn over constantly, and only occasionally as the starter motor is activated is the problem. Here's how we pursued the diagnosis:

> We then uninstalled the starter and tested it outside of the motor. Perfect working order. Spins quickly and quietly (no abnormal noises).

> We reinstalled and encountered the same problem again.

> We then noticed that the noise we were hearing was coming from an area we thought to be behind the alternator. We unbolted the 3 bolts of the alternator and were able to slide the unit out of the engine case by an inch and a half or so (we weren't able to get it out completely. From what I understand, the retaining mechanism for this is under the cover directly below the starter motor, however correct me if I'm wrong.) We hit the starter button and heard the sound of a healthy starter, with no grinding.

> Reinstalled the alternator with the same symptoms as before.

So, what I can conclude is that the problem lies with a component of the alternator assembly, or a component directly associated with it's functionality. Can you guys help me determine what it is and how to repair this?

Much thanks in advance! :icon_wink:

And if you're wondering...she's going to be a custom streetfighter when completed! (Purists: don't be too angry...she was beyond repair as far as the original plastics and fairings. Too far gone cosmetically for a restoration)