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TOPIC: Re:Idle RPMs and Tachometer question Forum Tools Post New Topic Show latest posts Rules

#449265 EddieDe (User) Gold Boarder Posts: 655 Idle RPMs and Tachometer question 1 Year, 5 Months ago   I ordered a fairing for my bike and I want to install a few gauges including a Tach, I experimented with a cheap car tach and it seemed to work without any issue however I'm not sure if the reading I got was correct. I hooked it up two different ways one way read about 750-800 rpms the other about 400. I'm not sure what the actual idle speed should be so I don't know which is correct I would think the higher one but I want to make sure. As a side note the higher one was reading off either coil the lower was when reading of both coils using a diode and resistor set up to isolate the coils from each other.   Logged       The administrator has disabled public write access. #449268 billmcc (User) Fresh Boarder Posts: 51 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   Idle should be 900 to 1K. I run my tach off one coil. Idle @950.   Logged       The administrator has disabled public write access. #449269 old dog (User) Platinum Boarder Posts: 2159 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   Think you had it right the 1st time. You need about 900 rpm to keep the idle speed oil pressure up.800 is a little low for my liking. bill   Logged     110 cu in., PR/JE 10.25:1 HC pistons, PR Cam, PR adjustable push rods, PR stage II ported heads (2mm oversize valves)   The administrator has disabled public write access. #449317 About_Time (User) Been there, swore at that! Platinum Boarder Posts: 1233 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   Was the engine fully warmed up when you took your idle readings? Reason I ask is my 04 will idle a bit slower when cold once the choke is off and once it comes right up to temperature it idles at about 950. If that idle speed was after a ride I'd definitely bump it up some. It might not lope as nice but it's better for the engine. Like Bill and old dog have already said, you had it hooked up right the first try.   Logged     2004 Roadstar Silverado Marshall Gold/Beach Sand Tan Lots of chrome stuff   The administrator has disabled public write access. #449408 grumpyroger (User) Be yourself, Everyone else is taken! Gold Boarder Posts: 814 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   What kind of car tach did you use, I think the price these thieves get for a "M/C' tach is outrageous, that and I am a cheap arse!   Logged       The administrator has disabled public write access. #449422 Curt (Moderator) Never to old to ride! Moderator Posts: 14922 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   Most auto tach's don't work with a v-twin the are made for 4, 6. and 8 cylinders. Barons has a good bare tach without the housing for around $50. Without know if the tach is reading properly and made for the v-twin you can't really set your idle rpms properly.   Logged     My Site Black Ice is Shiny, Black Ice is Deadly, Ya Wanna Ride My BlackIce?   The administrator has disabled public write access. #449424 grumpyroger (User) Be yourself, Everyone else is taken! Gold Boarder Posts: 814 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   Thanks Curt....guess we'll just wait n see how much my kids love me come Birthday time...Ride Safe my Friend!   Logged       The administrator has disabled public write access. #449427 texasscott1 (User) Two of a kind Platinum Boarder Posts: 2539 Re:Idle RPMs and Tachometer question 1 Year, 5 Months ago   The diode and resistor setup, with the diodes and resistors in parallel, you described is known as a "single fire adapter" and is usually used to adapt a dual fire tach to a Harley with 2 coils. I'm surprised at the results because the diode and resistor setup was sending twice as many pulses to the tach than when it was hooked to just one coil. Because it fires once per revolution our shop tach has to be set in 2 cycle mode to get the correct rpm's from a Road Star. Does the tach have a switch for different numbers of cylinders? If it does then 4 cyl should work when hooked to one coil. The inductive test tach I have at home reads correctly when hooked to the plug wire in 4 cyl mode.   Logged     Last Edit: 2012/01/08 10:08 By texasscott1.   My 99 Standard Test Mule Scott B.   The administrator has disabled public write access.

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