Hello to All, Have a 1960 with what appears to be original generator w./tach drive, Tach is erratic during acceleration and fairly stable at a constant speed. purchased repair kit. New shaft
that holds large gear will not go thru tach housing slightly too big but original shaft goes thru housing easily with a little play. So I'm wondering if old shaft is worn out and new shaft should be
carefully tapped thru tach housing unit?????? Or should I use old shaft and try replacing tach cable or maybe tach itself needs to be R&R'd? Any help or thoughts appreciated. TIA

 

Hang on to your original shaft. Unless its visibly worn (grooved) I doubt it or the gears are your problem (check the big fiber gear for wear). I'd be leaning to the cable. Try removing it and using some proper speedo cable lubricant. Whatever you do, do NOT force the repro shaft into your tach housing. If it does not fit smoothly and turn freely, please send it back to where you got it and tell them, so others can avoid this problem. You can rig a test cable to the back of your tach and connect to an electric drill (running in REVERSE) to see if the problem is in the tach itself.

 

Before you get get too hinkey with things...try some Kable-Eze graphite lubricant (Amazon or FLAPS)..

Disconnect the generator end of the cable and wrap a towel around it and hold it upright, dump some lube in it and shake vigorously, then repeat once or twice and reassemble - give it a 100 miles or so to get the lube worked up into the cable sheath.

 

You've always been there for me in the past and I really appreciate it. Think I will try the lube with the original cable first and if that doesn't work I have a new cable that
I will install. FYI, somewhere on the internet there was what I think is a GM fix for a erratic tach by inverting the entire housing 180 degrees, I tried that and was surprised
to find out that even 180 *s out the unit fit like a glove on the generator but the tach needle was even more erratic. Many thanks again............

 

Besides great advice already given, I am still thinking of more suggestions for your situation but for now make sure your generator belt isn't slipping to start with. For now?

 

I used to have the exact same problem with my first '60 with a tach drive gen. Sudden acceleration would cause the tach to lag behind. This was always my indicator to tighten the belt.

 

Yes - there is a TSB about flipping the tach drive setup - it helped at times but won't correct a sticky cable or bad head unit.

 

Flipping the Tach housing might help with a NEW cable and housing as supplied back in the day to correct an alignment / angle customer noise complaint, but it won't do a thing for a worn tach or dry cable. If you can reach up there behind the Tach (remove the seat for more room) unscrew the cable housing from the Tach andl pull it down a bit, that will allow you to pull the cable core out of the housing and clean and lube it without having to remove the entire casing. I like to use Syl-Glide on the cables, comes in a small tube and NAPA carries it. Don't get any grease up too high near the tach itself or it will mess up the speed cup. Just thread it back in when you are done. Also, clean and grease the tach gear housing on the back of the generator as well. A good medium body synthetic grease works well on the gears and shaft.

 

All good advise, will check belt out tomorrow. Thxs