Tach/speedo repair

maia · Post by **maia** » Sat Aug 13, 2011 5:55 pm

my tach is acting crazy and I'm thinking of sending it to a repair shop for some maintenance. Bill silver says I will just ruin it if I continue running it like this. Does any one have experience (good) with a repair shop. Any suggestions will be appreciated, thanks.

G-Man · Post by **G-Man** » Sun Aug 14, 2011 3:35 am

You may want to lube the cable or (very carefully) the input bearing on the tacho first. Often the 'crazy' needle syndrome is caused by high friction in the drive which winds the cable up. When the friction is overcome the needle races around the clock momentarily before the process begins again.

G

maia · Post by **maia** » Tue Aug 16, 2011 6:39 pm

Thanks gman, I decided to disconnect the tach cable from the engine and chuck it in a drill so I could straighten out the cable and see if the tach jumped all over the place , well it didn't. So i removed the drive from the engine and nothing wrong was apparent so carefully reassembled and hooked up the cable and now a nice steady reading from the tach! Don't know what was wrong but the forum saved me about $300 by not sending it to a speedo shop. Thanks guys!

G-Man · Post by **G-Man** » Wed Aug 17, 2011 2:17 am

Maia

Great news! Did you lube the cable? It might help avoid the problem in the future.

G

davomoto · Post by **davomoto** » Wed Aug 17, 2011 9:38 am

Maia,

When you removed the drive from the engine, did you remove the housing as well? There are two thrust washers on the drive gear. One sits on top of the gear, and one below. If you didn't remove the housing, odds are that the lower washer is sitting in the housing, and can get caught in the gear.

Davo

maia · Post by **maia** » Wed Aug 17, 2011 6:38 pm

The cable is well lubed thanks but I took it out for a spin today and the tach worked fine until upper rev range where it stated to jump around again so I will remove the housing (just removed the drive before) and check on washer positions. Thanks. I'm dealing with persistent and very frustrating carb problems but Imight as well fix the other stuff while I'm frustrated. No one should sit in a carport for 25 years!