My R1100RT has been sitting idle for 1 1/2 years. The battery was totally dead even though it had been on a maintainer. I purchased a new battery and installed it. The bike fired right up and seems to run just fine. I have only done some short rides since and have noticed that the tach does nor seem to indicate as mush RPM as I think the bike is turning. I know what the. Ike sounds like and what the RPM should be at various speeds and gear positions. I am quite sure that the tach is not accurate. No bouncing of the tach….no misfiring…but I suspect that Hall sensor is original and may be ready to give me grief. I hope someone has an idea what would cause this malfunction of tach. Fuel gauge and oil temp and clock all working fine. Engine runs fine and seems to idle at the normal 1200 RPM by sound….tach reads 1400-1500 at idle….idle does not sound high. Any ideas are appreciated.
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Strange tachometer behavior
- Thread starter billyfeet
- Start date
cajunrider
Member
Not sure about the RT, but the C won't run with a bad Hall Sensor... I wouldn't think that's your problem.
pauls1150
MOA #24991, south of Los Angeles
Your tach's pin #2 is driven directly from pin 19 ("Z1") of the Motronic, and this is also connected to one side of your ignition coil. While the HES (High Energy Spittensparker) for these years is known to have insulation problems within its sub-harness, this typically causes coughing and spitting of the engine, so it's "possibly" not the HES causing the issue, but it may be about to fail.
Pin 3 of the tach is ground; pin 1 is the +12 volts.
You can use an inductive (clip on, no actual electrical contact) timing light just to see if you have good consistent spark on both sides; also try to trace the tach's wiring back upstream, there may be something goofy going on there.
Pin 3 of the tach is ground; pin 1 is the +12 volts.
You can use an inductive (clip on, no actual electrical contact) timing light just to see if you have good consistent spark on both sides; also try to trace the tach's wiring back upstream, there may be something goofy going on there.
