I've asked this in countless forums before yet nobody can give me a definate answer.
On a 300ex does it fire the spark plug every revolution or every other revolution?
I'm about to order a tach and i need to know for sure.
Thanks alot!
Mike

 

Every 2 revolutions. A 2-stroke would be every revolution.

 

Ditto.

 

Yea, but this gets confusing, as some 4-strokes (like the 400ex) fire on every revolution. I don't know why, must be to ensure efficient detonation or something.

 

it depends where they get the signal to fire the coil.... the 400ex motor is triggered off the flywheel, so it fires the coil every revolution (it can't tell if the motor is on the compression or exhaust stroke).

Some 4 strokes get the trigger off the camshaft so they fire the coil every other revolution.


Make sense?

Leo

 

01TRX400EX is exactly correct. I have a tiny tach model #4962nr* and it works prefect with my 4 stroke quads and XR's.

 

Who makes this tiny Tach??? I have been looking for a tiny tach for months now with no luck. PLEASE HELP ME!!!!

 

To add to that when 4-strokes fire every revolution in is usually designed that way for emissions reasons. It helps to ensure that all fuel is burned and it reuces NOX gasses.

 

I picked my tiny tach at a Briggs and Stratton (my job) repair shop as we sell them for generators and adjusting governors on lawn tractors. I paid $30 for it. Dennis Kirk also has them but any Briggs dealer can order one I would also pick up a gasohol tester Briggs part Number 100023 as it is only $5 and can detect any alcohol in fuel so you dont run nasty gas.

 

NOX is a result of high combustion temps... I don't know how firing the plug on the exhaust stroke would lower nox??

Leo