New battery fitted today as poor starter! New battery does exactly the same and does not start it but as soon as I connect my jump unit up it fires straight away any ideas? New battery was holding 13v old battery just under 12v

 

Sounds like your new battery is discharged. New batteries do need to be charged before use.

Use a meter to measure the voltage right on the new battery terminals while you are attempting to start the quad (i.e. the solenoid is clicked and the starter is attempting to turn). What voltage do you measure?

If you measure above 11.5 volts then measure the voltage down at the starter motor under the same conditions (attempting to start). Place the red lead on the starter motor input post, and the black lead on the starter motor case. What voltage do you measure?

 

Thanks for helping again! Battery is measuring 12.56v with nothing on, turn ignition key drops to 12.31v when cranking drops to 10.42v? Soon as I jump it it fires nicely although has big misfire at high speeds if it's related? Do you know what spark plug gap should be set at?
Thanks again

 

So the key question is whether your new battery is just bad, or discharged. Have you tried charging it? Be sure that you use a charger designed for motorcycle batteries. Do not charge it at a current any higher than 2 amps. Higher charge current will wreck the battery.

Did your new battery come with the battery and the acid separate? Have you checked to make sure all six of your cells are full?

I don't think the high speed misfire is related to your battery.

I don't know what the spark plug gap should be. I set mine at 0.030" and that works fine on my quad.

 

Battery came with seperate acid pack and are all full, charged with 4amp charger ( done before reading your 2 amp bit) battery now reading 12.68 with nothing on then ignition on drops to 12.32 and on cranking is 10.43, tried a spare starter motor aswell and still the same

 

Sounds like a bad battery. It's probably a bad cell. Take the battery back and get a new one.

The 4 amp charging will damage the battery over a time frame of months - not days or hours - so this is not related to problem with a new battery.

 

Had battery checked each cell is ok and holding over 12v, any other ideas? It's like there isn't enough fuel going through to keep up with the spark as i have found if i hold throttle in full when cranking it will fire, is there any wayof adjusting carb as it's new, and any ideas on the miss fire/rough at highspeed full throttle

 

Your brand new *charged* battery is dropping to 10.43 volts right on the battery terminals when cranking the starter motor. That leaves only a few possibilities:

1) The battery is bad (or not fully charged up)
2) The starter is drawing way too much current

Possibility 1) is the most likely culprit. Who tested this battery? At what current load did they subject the battery to when they measured 12 volts? How did they determine each cell was OK? In other words, did they know what they were doing? The reason I say this is that often the best engine mechanics know absolutely nothing about electronics and just muddle their way through - making things up as they go along.

Question for you: Did you really test the battery voltage *right on the battery terminals* (and not the lugs that bolt to the battery terminals) when you got 10.43 volts? This is important since it is the only way to eliminate bad connections at or nearby the battery.

I'm assuming that when you jumped the quad battery to your car the starter motor spun at the proper rate and the quad started, right? And when cranking with the bad battery the starter spun slow. Am I still right? So providing an adequate voltage and current source from your car battery starts the quad up fine? If so, this sounds like a bad quad battery again... It just isn't up to the task...

Lets assume for the moment that your starter is drawing too much current (scenario # 2). It's not likely the starter because you've changed it. It's likely not the fact that the engine is too hard to turn or else you would notice other problems. Engines that are too hard to turn are rare and are usually on their way out. You'd notice other things like blue smoke out the exhaust, strange horrible sounds, etc.