No Spark Honda XR 650L Single Cylinder Motorcycle with Starter

Maintenance/Repairs
1

This is the street version dirt bike. So it is like a really simple car. It has a battery, starter motor, keyed ignition switch, ICM (ignition control module), coil and that is about it.

It cranks fine (for at least 10 minutes without draining the battery).

I have try tracing wires, disconnecting them, and measuring Ohm resistences, but get no spark after it sits around a week.

After dissassembling it, it periodically starts, I can go for a ride, turn it off and it starts right back up every time and usually a day later.

Would this be a coil with too much intermittent resistenance to block the charge or a battery with not enough cold cranking amperage to over come initial starting resistance? It does crank over quite well.

It seems to start (when it does start) when it is warmer out (65 degrees) and not start at lower temps (say 40 degrees).

But mostly not start after having been left for a week unstarted.

I went for a 2 hour ride for about 100 miles. Next day I wanted to see if it started and it started right up (this all happened last weekend).

I tried starting it this weekend (and have put the battery charger on it too, which really charged the battery), and no luck.

Any suggestions would be appreciated.

2

How old is the battery? How many volts does it read?

You sure you’re not getting spark? What if the gas evaporates out of the carb over a longer period of time or the choke/carb isn’t providing enough gas when it gets colder? Have you tried spraying starter fluid to see if this helps it start?

What year is this bike? How are the spark plugs?

3

It is a 98. It is the dual purpose model.

I bought it with 3k miles 7 years ago and have 9k on it, and replaced the battery about 2-3 years ago. I could check the voltage. Are you suggesting when cold it is not creating enough voltage to overcome correct resistance to allow the coil to fire in the starting circuit?

It does drive the starter great, but your point is so what because it is not sending enough battery voltage to the coil? Meaning it needs a minimum battery voltage to charge to coil so it will force the coil to discharge at the spark plug irrespective of the fact that it can crank and crank and crank the starter motor?

So your point is that the intial battery voltage may be too low to charge the coil and have it discharge?

Would the temperature of the battery affect its’ ability to build more charging voltage? In other words, like a flash light that is warm versus cold, the warm want works better and has more voltage due to temperature?

Is that possible? I have had a lot a shop classes and work on a lot of stuff, but clearly forget things as not being a regular mechanic.

The orginal Honda plug was in it for the first 8k and worked great and I got another new one, just because I thought it was a good idea, and that one has been in there for about 1k. I don’t think it is the plug. Both are OEM plugs of the exact same original type.

It cranks the starter motor great. I mean it cranks forever until it starts wearing out the battery charge. And then I put the charger on it and it easily charges the battery and it cranks some more (no problem).

I take out the spark plug ground it and nothing. It somehow (I am speculating here) seems to start when it warms up, and like I said before starts right away the next day after it has been run with no seemingly different outside temperature differential
(and it runs great).

I thought it might be the coil. Perhaps too much resistence in the coil (I measured it and it appeared out of spec by a little too much, but it wasn’t much. And since it runs fine once it starts, how could this be the coil?

Thanks for the help, I am one of those guys that likes to learn and figure out things myself.

4

I tried starting it again. Garage temperature is about 50 degrees. Cranks fine. I didn’t take of the air deflectors (deflect air to cylinder) to remove the plug again to ground it, but have done that numerous times in the past without getting a spark.

Do you know a Honda owner’s web site where a lot of others might know the answer?

It really is a simple system.