Crank sensor

[otter814]

My friend has a basket case bike. 2003 fly with a 98 evo. The shop that put it together and sold it to him . He Had taken it back to them with fuel injection problems. They talked him into putting on an S&s carb instead . Then he blew a base gasket and they talked him into rebuilding the motor at which case they put it back together and it pulled a stud so They went in and put the bigger sleeve they could for the stud and it still pulled back out so now he's looking to replace the motor my question is does a carbureted bike need a crank sensor any ideas would be helpful I'm going to try to put this thing together for him

[Burnout]

Depends on the electronics used.

[Pirsch Fire Wagon]

Yes.

The other options are points or Cam Sensor. 

Either way, it has to get a signal when the Piston as at TDC so it knows when to provide power to the coil.

Electronic Signal Types work on a Square Wave when passing a window cut into the Crank (reluctor gear).

It's either on/off depending on the position of the Window. Depending on if it is being used on a conventional or EFI the signal could produce spark, or the Fuel System could start injecting fuel into the cylinders, or both.

Points merely open/close the circuit on an eccentric.

Both are adjustable to add/remove timing. Points often have a weight that moves eccentrically to advance time under RPM.

[kd]

It may be time to regroup if he is keeping it.  There are plenty of early twin cam engines (and transmission) sets out there for reasonable cost.  Putting it back to OEM may be easier and less expensive.  They were Delphi so that's OK.  The 98 Evo was M/M. He can probably get a few bucks for his carb and engine etc. (parting it out even).  His M/M is actually worth something these days too.

[hbkeith]

He has already got rid of the junk MM system , replace engine because of a pulled stud ? get someone to fix stud proper , keep the reliable EVO

[capn]

If it is an evo motor it does not need the crank sensor. Just cut the wires and run an ignition that fits under the nose cone or cam cover. It gets the signal from a rotor bolted to end of the cam.

[Burnout]

Weren't there carb'd Twin Cams? If so use the ignition module off one of those with the crank sensor.
They also had a MAP sensor on the intake.

[Scotty]

This whole thread seems confusing. 

So I take it he owns a 2003 FLH frame with a Evo motor fitted.

Firstly Evo motors DO NOT HAVE a crank position sensors they only have cam position sensors.
So you cannot run a twin cam ignition on a Evo motor as you need the crank sensor signal.

Early twin cam motors had both cranks position sensor and cam position sensor and they did away with the cam position sensor in most 2001 models and all by 2002
If he put s a twin cam motor back in he will need a twin cam ignition for a carb bike and preferably a 2001-2003 one as you don't need the cam position sensor.

If you want to go Delphi EFI then you don't need a cam position sensor either as they only work of a crank position sensor.

Ignitions for Evo and twin cam are completely different and not interchangable.

For a start Evo ignitions use a VOES and twin cam a MAP

[capn]

Fuel injected Evos did use crank sensors.I have a 97 motor sitting in my spare bedroom closet.To do away with the stock ignition either just cut the wires at the sensor or remove it and get a plug.

[Scotty]

Fuel injected Evos did use crank sensors.I have a 97 motor sitting in my spare bedroom closet.To do away with the stock ignition either just cut the wires at the sensor or remove it and get a plug.

I forgot about the MM bikes my bad and you are correct but it will not work with a twin cam ignition module.