I have a klf-400b 1993 electrical issue. I can hit starter button and get no spark but as soon as I let off button I get a spark. I have trouble shooted till I am brain fried. Can anyone help?

 

I've had this problem on Hondas, and never cured it. The owners get used to blipping the start button as one of those sparks will "catch" and, once running, the bike is fine. It also works OK on the pull start as a rule. Some say it is caused by a dirty trigger coil on the alternator.

 

That is an interesting problem. I suspect that running the starter motor is drawing down the voltage of the battery too much for the CDI box to work properly. The starter may draw as much as 100 amps and take the battery down below 10V.

That points to a possible weak battery, but could also be a problem with a weak CDI box or a tired starter motor.

First thing to try is starting the quad with a big battery or 2 good batteries in parallel.

 

Steven, what did you find out?

I too have heard a weak battery can cause this. The starter pulls the battery down and the moment you let off the starter there is more juice to produce spark. I'm in the same situation with my Concours street bike. The battery is 5 years old but turns the engine just fine. I took the battery out of my atv and because the connections were on the wrong side, I had to use jumper cables to connect it. The concours started right up. I'm probably going to order a new battery this week.

My bike used to have regular coils, 1987 model, then I switched to stick-coils. I've been told the stic coils don't produce as strong of a spark as the OEM coils, reason being the oem coils had to fire a less than perfect air fuel ratio whereas the stic coils were designed for fuel injected bikes and therefore don't need to produce as strong a spark because the air fuel ratio is much better.

 

The weak battery idea doesn't take account of the fact that CDI ignition draws power for the spark from the alternator coils direct, and will spark happily with no battery there at all. On some bikes, the Honda 450 is one, a faulty regulator will draw all alternator power, causing a loss of spark but I can't see a battery with enough grunt to turn the engine over taking too much out.