Tach needle erratic

[caliph23]

Yesterday after about a 30 min. ride. The electronic tach needle started bouncing around wildly. Has anyone else had this problem? Not sure if this
indicates an internal problem with the tach or something on the ignition side of things. No other symptoms except that the bike is very hard to start when cold. any thoughts or advice?

[Barry]

Can be ignition and closing up the plug gaps might help depending on what year bike it is e.g. points ignition could easily have a weak spark but less likely on electronic ignition unless the coil is faulty.

[caliph23]

1982 R65LS

[montmil]

Difficult hard starts can often be caused by a clogged jet in one or both enrichener circuit fuel reservoirs. Drop the bowls and run a thin, single strand of copper wire through the brass jets. You need fuel in those small reservoirs to feed the enrichener "carburetors" on the Bings.

[Bob_Roller]

The tachometer gets it's signal from the ignition module under the tank .

I believe there is a black wire from the module to the ignition coil, should have two black wires on one of the terminals, one goes to the ignition coil, check for security, corrosion, etc....... .

I had hard cold weather starting with my '81 R65, had a bad coil, the primary circuit had less than .5 ohms, should be around 1.5 ohms .

Replaced it with a DYNA ' brown ' coil .

If you still have the OEM black and gray coil, replace it !!!!!

It's a known problematic part .

[Red_Hen]

Yesterday after about a 30 min. ride. The electronic tach needle started bouncing around wildly. Has anyone else had this problem? Not sure if this
indicates an internal problem with the tach or something on the ignition side of things. No other symptoms except that the bike is very hard to start when cold. any thoughts or advice?

I'm in the middle of same thing.
Ignition problems & bike cutting out & dying - installed new hall sensor but bike still quit. Installed new ICU from euro moto & problem solved but tach jumpy & needle jumped off!

It rained & snowed & bike wouldn't start - weak spark. The coil was a black Bosch coil but I bought from a guy for cheap - I'd replaced the crackomatic several years ago.
Matt Parkhouse borrowed me a dyna blue 0.7 ohm coil & bike started & tach didn't jump anymore.  Bike still cutting out - am ordering new bean can icu & ignition harness & will report my findings.  These ignition systems can be very problematic and tough to pinpoint.