tach fix

[mraf]

My tach has always been slow on my 86. This was nothing to be very concerned about but it was always on my mind that it could be this way because of something electrical about ready to fail. What with the tach receiving its signal from number 2 coil which in turn runs it through the TCI box then on to the tach. I have always read anything on this site that was tach related in hope of pinpointing what it was that made mine run slow. I have been told that my TCI could be faulty, my #2 coil faulty, bad ground to maybe just a boggy tach. Well the search is over! After running the diagnostic check of the wiring to the TCI. NOT IT. Check of coils. NOT IT. Adding a second ground wire. NOT IT. The problem was the tach itself. I removed it from the housing to look it over and clean it using some electrical contact cleaner. My brother-in-law was here when I took it out and he said that it just looked as if it needed lubed up to free it up. He grabbed the can of Sili-kroil and began to ever so lightly lube the needle mechanism while moving it toward redline and letting it go. After five minutes of this. THAT WAS IT! It is now free as the RPM it reads. Upon further inspection it seems that on the backside of the instrument cluster box that houses the tach and speedometer, on the tachs side of it. There is a unplugged hole that looks as if it should hold a light but there is no provision for one there. Being a 86 this hole has let moisture and the elements into the tachs cluster for 22 years a very unnecessary and troublesome hole that is now plugged. More than enough time to gum up my tach. So if your tach is boggy don't rule out that all it might need is a good clean & lube.

[Yammer Dan]

Better than the TCI Glad you found it.

[nowindinmyhair]

What do you mean by having a "slow tach"? Mine is slow to respond until it warms up and then seems to react appropriately. This seems worse in the cold weather. I am not sure if its the tach that needs to warm up or something else. Does this sound like the problem you had ? If so, how big a job to take the tach out ?

 

Thanks

[FROG MAN]

I'm glad you found it. Meter movements do need lubed once in a while. I have an 86 waiting for tach repair attention but as usual no time to get into it right now.

[mraf]

What do you mean by having a "slow tach"? Mine is slow to respond until it warms up and then seems to react appropriately. This seems worse in the cold weather. I am not sure if its the tach that needs to warm up or something else. Does this sound like the problem you had ? If so, how big a job to take the tach out ?

 

Thanks

Mine was slow to move cold or hot, it would eventually come to the correct RPM but just took its time. Your tach should fluctuate as rapidly as the engine RPM not get there when it can. Like I said before there could be other reasons {I.E. T.C.I. or number 2 coil.} I had ruled these out before I started to remove it for cleaning.

If you wish to go on in doing this, you might as well clean and lube your speedometer also being that the bearings need periodic maintenance too.There were instructions on this I think in the technical section of this site.

You have to remove the chrome Venture valance,headlight valance,headlight,windshield, unscrew the speedometer cable, unbolt the 2, 10mm bolts holding the instrument cluster to the bike. You can see these by looking up into the headlight hole. Lift the cluster up enough to remove the 4 philliphead screws holding the instrument cluster cover on and remove it. Now remove all the phillphead screws that hold the instrument cluster halves together.They are around the outside of it on the back. After removal open the cluster. You are now seeing the tach,crystal readout,voltmeter,gas gauge and speedometer. Remove the 3 small philliphead screws that hold the wires that run the tach and the 2 small nuts and washers that run the voltmeter the two{Tach & Voltmeter} are made to come out as one unit. You can now pull the tach,voltmeter independent of the cluster. Everything you do from there on is up to you.

[6m459]

While opening the insturment panel beware, one item is missing from the disassembly steps listed in the previous post.

 

Now remove all the phillphead screws that hold the instrument cluster halves together.They are around the outside of it on the back. After removal open the cluster.

 

 

I found out to my cost, that the panel illumination adjustment knob is held on by a very small phillips head screw deep down the centre of the knob. Jeweller's screwdriver size. I wish I had known this 12 hours ago.

 

BJH