headlights on to charge battery

[jasonwayne222]

just got an 05 and need to know if u have to have the headlights ion to charge the battery. also is there anything else you have to do to tighten the chain other than adjusting the bolts on both sides

[yfzrider690]

Yes you do have to run with the headlights on to charge the battery unless you get the resistor that fixes the problem. I'm not sure about the swingarm.

[jasonwayne222]

ok and i figured out the chain deal just didnt see the other two big nuts

[yamaha_maniack]

have to have the headlights on while running for the batteries to charge? is this only an 05 problem, or does the 2009 yfz-r do this too? this would be nice to know.... never heard of this before. and i normally would help you with the chain tension thing, but the new 09's are different and use a cam system (i believe it is called) instead so it is a whole different story..

Thanks!

[yfzrider690]

The headlight problem is only on the '04 and '05 models. They fixed it for '06 and up.

[yamaha_maniack]

alright thats what i would have figured, but still good to know as i have a buddy that has an 04 or 05 model or both.. so i will let him know.. does it just not charge at all without the lights on, or what?
Thanks!

[yfzrider690]

Ya it won't charge at all and eventually the battery will go dead. You can buy the resistor that they put in to fix it for around 40 bucks I think.

[yamaha_maniack]

alright i will let him know about this! So it will just like die while riding it if the light switch is off? he doesnt have the lights installed anymore, so it wont make a difference to leave the switch up. does it matter what position it is in? I know that at least one of his yfz's is an 04-05 but the other one might be an 06...

Thanks again!

[yfzrider690]

It won't die when you're riding but when you stop to take a break or something it might not start again. The position doesn't matter.

[yamaha_maniack]

alright, thats what i figured..
Good thing this came up! i have never even heard of it before!

Thanks again for all of your help!
I appreciate it!

Later

[yfzrider690]

You're welcome, glad I could help.

[jasonwayne222]

ok so the block on my buddys 04 through a rod so we rebuilt the whole motor with the block off of a 07. So do the headlights still have to be on to charge. I would think that the different block wouldnt change anything since the chargin issue is through the electrical system. Also is the stators the same part number. His batterys not charging and its brand new. he checked the levels and it was real low. so maybe the rectifier is bad and under or over charging the battery. not sure but he has the stator off the old block and might try changin it out to see.

[jasonwayne222]

bump need answers please

[miles Machine]

that wont help. the problem is that it dosnt have the resistor kit on the 04/05 harness, and the newer ones do...check voltage at the battery while at 3000 rpm with lights on and off the bike it should be around 14 +- .5 volts if there low with the lights on and off then its a good chance that the rec is bad...which you can also test that too with the multi meter to make sure the diodes are good

[jones711]

Were can you find a resister kit