Motorcycle tachometer (rpm's) bouncing everywhere?

Question

when i take a ride for a little, it starts to bounce around like crazy. also the engine gets strong and weak, strong and weak... head lights gets weak and comes back to normal.

whats the problem? do i have to change spark plugs? or is it a weak battery problem? or etc..

Answer 1

Sounds like a bad battery connection or a bad ground.  Spark plugs would have nothing to do with the headlight getting dim then bright.  A weak battery would be worse when you first start the bike, not after it has been running a while.

I ride a different make of bike, but it is notorious for a similar problem.  I frequent a forum for my bike.  The recommended repair is cheap and simple.  They recommend using star washers on both sides of the battery connections.  Use 2 washers on each connection, one on each side of the cable.  About a 50 cent fix and a little time.

Answer 2

Sounds like a voltage  fluctuation to me.

Prime suspect for such a condition would  a Faulty Voltage Regulator.

There's other things also,,,but they all rank pretty far down the "Top 10 List of possibilities"

Good chance the battery is Weak or damaged.

Normally a battery can absorb a substantial voltage swing,,,and sort of Buffer it due to the battery being steady output.

A bad Regulator can damage a battery,,,so that adds a bit of suspicion.

So,battery to be tested also.

Things like Bad Connections,,,corroded or loose wires can also cause symptoms like your bike's having.

But the place to Start Checking is the Regulator and Battery.

Then go from there.

Good Luck,,,