Topic: Tachometer sluggish

[jbailey]

I have a problem I've never heard about before.  My 75 550 has not been ridden for a few weeks just because of my busy schedule.  I am planning on taking a ride tomorrow with my son, so I took it out of the garage to clean it up and lube the chain and such and noticed that the tachometer is very sluggish.  What it's doing is the needle moves VERY slowly and I'm not sure if it actually gets to the correct position or not since I didn't take it for a ride.  When I shut off the bike I noticed that it took about 5 seconds for the needle to drop to zero from idle.

Any idea what the problem might be, and if so is it something I can fix or lube myself?

[heffay]

http://www.cb750cafe.com/

that's carpy's website... he's a member on this forum.  if you look at his items for sale you'll see guage decals... in the description and details of this item there is a detailed disassemble/assemble instruction.  it helped me.

[mrbreeze]

Yeah,I'm having the same problem with mine.I don't know if there is a rat nest going on in there or what but Carpy came to mind for me also .If it has to be torn down and repaired or lubed or even replaced,I would like to go with his setup. I like the face plates he has plus the chrome housing(looks so sharp!).I did put a new cable seal in mine today and it stopped leaking oil but it still isn't reading properly. I guess it is a case of--- What do you expect for 30 years old?

[mgilvary]

Try this:

Disconnect the cable from the tack and shoot some silicon spray into the housing all around the spindle that the cable attaches to. Then reconnect everything and start up the bike to distribute the lubricant.

This trick helped me silence and steady a very noisy and jumpy tachometer (though I've had to reapply every 4 months or so).

[eldar]

You can pull most of the housing apart but i do not recommend pulling off the trim ring that holds the back and front together. It is almost impossible to not cause some kind of damage. You can still do most of the lubing with that part together anyways. Do not use a spray though. Get something with a tube that bends. Then drip a couple drops on. You could clean it with some compressed air first that is at low pressure. Under 90 psi.

[jbailey]

I took her for a ride today.  It seems like the tach is registering correctly, but it takes a minute or so for the needle to get up to the correct position.  I pulled in the clutch from 4500 RPM's and it took about 30 seconds to get down below 2000!  When we stopped, I shut off the bike, got off, removed my helmet and then notices that the tach was still coming down.  It was the quietest 1000 RPM's I've ever heard!

I came to the same conclusion that it needs to be lubed.  I will have to pull it off the bike and try the above suggestions.  This would also be a great time to replace the faces if I do end up disassembling the tachometer.  Has anyone ever seen replacements for the 550?

[Jonesy]

I bought a CB360 that had a sluggish tach and it was worse when cold outside. I carefully pried back the ring holding the cases together and found that some kind of oil or other lubricant had turned to a sticky, gummy substance that was making everything hard to move. I carefully cleaned everything and put it back together. It's now nice and responsive.