79 750F Tachometer troubles.

[iddqd]

Hey everyone! Let me just thank you all for the loads of information I've gathered from the combined wisdom on this forum, unfortunately I feel like I've finally run into a road block that I can't find the answer to, so Imma ask it.

Little background on the bike and me: '79 CB750F. Picked it up off of craigslist for $600, dude drove it all the way to my house so I know it runs. Restored a 67 Mustang previously so it's not my first time turning screws and troubleshooting, following manuals etc etc. Decided to just go through the manual and do the basic tune ups and branch off to the differnet components as I see fit.

To get down to brass tacks and not waste everyone time, P.O. was a 19 year old kid who's heart was in the right place, but the follow through on his repairs was off. I'm not even sure how but somehow he managed to damage the tachometer cable, rending it useless, and he decided to just JB Weld the whole port shut.
I on the other hand decided I want a tachometer so I blasted that piece with a propane torch and got it apart. I may or may not be regretting that decision because the piece that holds the cable onto the cam cover appears to be damaged, and I can't figure out what that part is called, so I can't find a replacement.

If anyone can be of some assistance, either a name for that part, or a work around to be able to connect the cable back to the gear and get the tac working again, I'd be very appreciative of that.

Here are some pictures that hopefully show what I mean. Sorry for the flipped images, but you'll still get the idea.







This guy...what is it called??

[Re-run]

Not much help, but if I were you I would just get a different valve cover. Save this one for a spare, just in case.

[iddqd]

It does look like it's designed to come apart, and all the covers I've been looking at have the same hole for the cable, but none come with that housing piece. Dunno if this sheds more light on the matter.

[Rodgil]

The part that drives the tacho is all part of an exhaust camshaft holder, and is shown in the exploded parts diagram for the cylinder head as item#3. The part number is 12213-425-305, is no longer available thru Honda, but do a google search for the part number. If you buy a second-hand one, make sure the cam bearing surface looks reasonably smooth. You will also need the seal that goes between the cam holder and the cover, p/n 91311-425-000.

[iddqd]

Damn. That's awesome, that's it right there. I had a feeling that it had more too it because the bottom felt like it was grinded down. Didn't even catch it in the schematics.

Thank you very much.

[evanjsilver]

Glad I found that thread. That housing where the tach goes in cracked on my bike too and I found a replacement part from Honda of Lafayette, LA. It was 38 new. Just out of curiosity, were you able to do the replacement without taking out the engine. In other words, is it possible to remove the valve cover without pulling the engine?

[TOOLS1]

It depends on what year, model bike you have. SOHC "K" and "F" models, no, you must remove the engine to remove the valve cover. However on all DOHC and SOHC "A" models you can remove the valve cover with the engine in the frame.
TOOLS