Hey all,
This weekend, I pushed the start button on my 48 and let go before it actually turned over. I heard a "click" sound while a puff of smoke came out of the engine. It started right up again and no problems since then, but I was just curious if anyone knows what exactly happened. It is just for my piece of mind. Thanks.

 

Sounds like you didn't hold the start switch long enough for the engine to make a complete revolution. It will happen more often when the engine is hot.

 

If you don't start in neutral the EMC will since the drag and assume that it is on the compression stroke and fire on the exhaust stroke. Doesn't hurt anything and it will fire on the next compression stroke. To avoid this issue always wait for the engine light to go out and start the bike in neutral.

 

Do you have documentation to back up this theory?
To my knowledge, the ignition is only going to fire based on data received from the Crank Position Sensor and clutch drag isn't going to change that.

 

phew, this happen to me once and I started freaking out, glad its not that big of a deal.

 

Thanks cHarley, you beat me to it... I was wondering what kind of sensor would sense the load on the engine and mistake it for a compression stroke?

I guess it sounds like a good explanation from someone who has no clue to another person who has no clue. Thus proving your (cHarley) signature correct.

 

Not a theory it's the way it works. Can get it for you if you can't find it yourself. The CPS has no way of knowing what stroke the engine is on. So the ECM monitors the crank speed and if it detects a drop in speed it assumes that it is the compression stroke however the ECM will quickly determine that it was not the compression stroke due to no increase in RPM. Clutch drag will and does affect the speed at which the starter turns the motor.

If you need more info please contact:

Shannon Babb
Service Technician
started Nov 1998
Master Of Technology / level 5 (highest level achievable)
PHD certified

Smith Brothers H-D (423)283-0620

Call Shannon and argue with him, he'll set you straight.

 

Prove me wrong call and talk to Shannon (423)283-0620

You know what happens when you assume.........

BTW just how is a CPS suppose to know what stroke the engine is on?
The kind of sensor that can determine engine load is the ECM and it does it by monitoring engine cranking speed. Maybe you guys should do a little of your own research before you start dissing someone.

 

Sorry dude, but you've been fed another piece of dealer crock. The ECM/ICM isn't going to fire a plug until it recognizes the index mark from CPS so that it knows where in the rotation cycle the crankshaft is.

Further, if "the ECM monitors the crank speed and if it detects a drop in speed it assumes that it is the compression stroke", just how would the ECM/ICM determine which of the 2 cylinders is on the compression stroke so it knows which plug to fire?

Next time you go back to this dealer, be sure to have them check your muffler bearings.

 

Dude I'm sure your a nice guy, so research it out yourself. The CPS only knows where the crank is in a 360 degree revolution, it takes 720 degrees for a full cycle. So the ECM determines which stroke the engine is on by monortinig cranking speed.

I'll say it again PROVE ME WRONG, do the research.

Or you can can resort to name calling a joke making to cover your own lack of knowledge on this subject....your choice.