Perhaps electrical? Yesterday I opened up the fairings, tail, tank, opened up the air filter for cleaning. I do not wash the bike mostly or even if I wash it I keep water away from the main engine area. Yesterday as I was cleaning the bike, I cleaned the outside area under the carbs with a cloth soaked in WD40 spray. When I started the engine today I noticed that the rpm needle was moving too freely. The idle rpm count for my bike is 1.5k but the needle would show 3.5k and as I drove the bike the needle would give too much counts of rpm and would go beyond the red-line limit even though actually I was riding below the 10k rpm range. I manually adjusted the rpm from the screw just under the carbs but nothing wrong about it, its just that the rpm needle is moving much more than it should. As I reckon, perhaps the WD40 spray went inside some engine area from somewhere, even though I took great care not to let that happen. Is it time to consult a mechanic or is there a chance that the needle will resume its normal movement once the aftermaths of WD40 have dried? All the cable connections are fine, what might be causing the problem?
Update! I think the problem was being caused because of something WD40 spray might have done, the rpm needle resumed its normal movement today since the WD40 might have dried up.
On the early FZR models the grey wire that fires the 2-3 coil splits off, one lead to the coil and one to the tach. Later models of FZR600 & 1000 had a separate grey wire running to the tach from the TCI box itself; I would assume the same was also true for the later 400 & 250s (try finding wiring diagrams for THEM). I haven't been able to determine yet if this is a discrete low-power circuit, or just the tach / coil split happening inside the box instead of in the harness.
