Honda CM400 speedo and tach not working

[system9]

I recently got this bike on the road, and realized that neither the tach or the speedo are working. Its an old bike, a 1981. The needles don't even budge or wiggle. The cables are intact and everything looks like it has been untampered with. Do these older analog gauges just die? I'm not sure what repairing the speedo entails, the tach cable goes right into the crank case i think, so I dont want to tear into that. But if someone knows some tips on trouble shooting a speedo on an older Honda please let me know. Thanks.

[pchast]

Ok, Dan

We likely need more information.... How long has the motorcycle been stored?

How do you know the cables are ok in their sheaths? Did you pull one and check it?
Are they solid to the far end and don't turn free in the sheath? Did you try and spin one
in the speedo or tach to see a reaction...

Pete

[system9]

Ok, Dan

We likely need more information.... How long has the motorcycle been stored?

How do you know the cables are ok in their sheaths? Did you pull one and check it?
Are they solid to the far end and don't turn free in the sheath? Did you try and spin one
in the speedo or tach to see a reaction...

Pete

The bike was stored for 8 years, I don't know if the cables are ok in their sheaths, i wasnt sure how to test that. But, lets say the cables are bad, what are the chances that the actual instruments are bad? Is it usually a case of bad cables? Or is there a way to test the instruments without buying new cable?

[Johnj]

Well first disconnect the speedometer cable at the front wheel. Pull the inner cable out of the outer sheath. Is it even there? Is it broke? Do the same kind of thing for the tach cable.

[foxracinginc003]

how do you disconnect the cable from the front wheel on the cm400? I thought I had to remove the screw on it but its not budging?...........

[Wrider]

First thing I'd do is unscrew the speedo cable from the back of the gauge. It should look like a silver cap with little grooves in it. That untwists. Might take a pair of pliers to do it if it's been sitting for that long.
It should then have either a square or flat thing sticking out of the cable. Get the front wheel spinning. Does that spin too? If not you've just found your problem. If so, then your gauge is dead.

[system9]

I unscrewed the cables from the back of the instruments. Upon inspecting the inner cables, about 2-3 inches of the cable came out. They were snapped. So that problem is now obvious, the cables are garbage. At this point does anyone have experience with buying an after-market cable that will screw directly on to the original gauges? Or should i start looking into replacing the gauges and the cables?

[Johnj]

Go to your local Honda Dealer, they will have or can order the parts you need. (We will gladly provide the part next Thursday as long as you pay for it today) Otherwise you can go to Bike Bandit or Old Bike Barn on the internet. Get the cables first. No need to replace the gauges until they prove to be bad.