lights dim with the idle

[des max]

hey guys quick question I have a 2000 vmax stock except for the delkevic 8 inch slip ons my lights are moving with my idle which fluctuates slightly so as the idle goes low the lights dim and then as the idle goes up the lights brighten it has never done this before has anyone else ever had a similar issue or know of the cause? any help is greatly appreciated thank you in advance!

 

[Tex85]

Probably an electrical problem, have you checked the voltage readings with a multimeter? Need to get some numbers then trace down the problem; could be battery, RR or something as simple as a bad ground.

 

[DMAN999]

Check your voltages as stated in this guide to see what the issue is:
http://www.vmaxforum.net/showthread.php?t=19108

 

[wayne z]

What is your idle rpm? Most bikes will do this at lower idle speeds. I never thought it was a problem, as long as the lights brighten off idle, I know the system is charging.

Ditto on checking voltage.

 

[des max]

thanks for the info and quick responses guys I really appreciate it!

 

[des max]

hey guys just an add on to my previous post I haven't been able to run the tests on the different electrical components yet but I took it out for a ride tonight and when I got home I revved the throttle in the garage and my headlight did get a lot brighter at higher rpms the bike was warmed up and everything this does lead me to believe that it is the battery and not one if the actual components. any thoughts on that guess?

 

[MaxMidnight]

The purpose of the battery is a) to act as a reserve and provide the shortfall when the alternator isn't providing enough power or b) to start the bike.

In most circumstances the alternator will be sufficient so I would be sceptical about your diagnosis.

#1 rule of diagnosis - don't guess and where possible measure so you are basing your diagnosis on fact.

A good start (which is really routine maintenance) would be to ensure that all of the earths are clean. It's also worthwhile breaking and re-making all of the relevant connectors in the headlight circuit.which will have the effect of cleaning them up.

If that is ineffective then you would need to get the multi-meter out.

 

[Miles Long]

The purpose of the battery is a) to act as a reserve and provide the shortfall when the alternator isn't providing enough power or b) to start the bike.

In most circumstances the alternator will be sufficient so I would be sceptical about your diagnosis.

#1 rule of diagnosis - don't guess and where possible measure so you are basing your diagnosis on fact.

A good start (which is really routine maintenance) would be to ensure that all of the earths are clean. It's also worthwhile breaking and re-making all of the relevant connectors in the headlight circuit.which will have the effect of cleaning them up.

If that is ineffective then you would need to get the multi-meter out.

Agree completely with MaxMidnight (known by his British Brethren as Professor MaxMidnight:worthy Electrical problems have to be approached systematically, eliminating possible cause(s) one at a time. A good multimeter is essential for a proper diagnosis to be done.
My vote for #2 rule of diagnosis - Start with the simple things first, which Max suggests-checking all grounds and connectors. I would add checking the headlight fuse/spring connectors as well. Any connection that is loose or corroded adds resistance to the circuit, cutting down available voltage.
Whether the above solves the problem or not, I would next check the voltage across the battery terminals at idle and as the bike is spooled up (stator maximum output is reached at 5K, but this is also a function of the type and condition of the regulator/rectifier) - then compare these readings to the voltage directly at the headlight connection(black - ground, yellow - high beam, green - low beam, or as the Brits say, "dip").
It is normal to see reduced voltage, usually around 1/2 volt or so. Many folks install a Headlight Relay Kit to alleviate this voltage loss, and to also protect the switches in the circuit.
Keep us informed as you check things out.
Cheers!

 

[des max]

awesome thank you guys for the responses I will post what I find out