Topic: 1976 cb550? headlight low power

[andymum]

Hi guys n gals

Right my headlight has low power through wireing loom but if I bypass that and go straight from battery to headlight it is bright as anything.
what could be wrong and best  and easiest fix please

thanks peeps

[Rgconner]

You have excessive resistance in the wiring loom. Most likely the switches.

Best solution? Start cleaning the contacts everywhere in the loom. Possibly replace/take apart the keyswitch.

Basically it is a bad design for long term. All the power flows through contact points that build resistance as they age. My keyswitch ate 4 to 6 volts before cleaning, and 3 to 5 after.

Ended up putting a relay switch in from HondaMan. Now I only see the dimming at idle, full light at 2000RPM.

And yes, that is more or less normal.

Doing the cleaning and the relay will take the load off the underpowered charging system. It is really just barely powerful to keep the system charged when running the headlight.

Part of the problem is 35w headlights can be a pain, and many people put in a H4 system with 55w bulbs.

Changing to a Phillips "green" bulb that reduces the wattage by 20% but still puts out the full light of a 55w really improved my charging issues:

http://www.amazon.com/gp/product/B00318V0B6/

[bollingball]

Andy Sounds like a good time to clean up all of your connections. Not just the headlight. Start in the bucket then the headlight sw. You may also be getting low voltage to the coils. If I were you I would put a couple of relays in for H/L headlight and one for the coils. look in FAQ under electrical or it may be in tips and tricks.Another advantage of the relays is they take the load off the switches

                                                 Ken

[IndyFour]

Hi guys n gals

Right my headlight has low power through wireing loom but if I bypass that and go straight from battery to headlight it is bright as anything.
what could be wrong and best  and easiest fix please

thanks peeps

It's most likely dirty/corroded connections and the old, dirty light switch.  Clean them all and lube with dielectric grease....you should see improvement.  While you're at it, I'd recommend doing this to all the connections you can find in order to avoid problems down the road.

The alternative is to wire in a relay in order to power the headlight directly from the battery.  I did this for both the low and high beam circuit (two relays in the headlight bucket) and it made a dramatic difference.  I'm sure you can find a wiring diagram here on the forum someplace if you don't know how to do that already.  I think you can also buy headlight relay kits already made up that you just plug in...but they are pricey.

Good luck.

edit:  bollingball and Rgconner beat me to it.....sorry for the redundant info.   

[Rgconner]

It's all good =)

Getting the info 3 times from 3 different people is always a good confirmation all of us are sane.

Or insane. I forget which one it is.

Just the place for a Snark! I have said it thrice:
What i tell you three times is true." - Lewis Carrol

[72500john]

just got a relay kit from hondaman for my 500. he makes them for the 550 also..sounds cheaper than a swithch!!??

[Rgconner]

just got a relay kit from hondaman for my 500. he makes them for the 550 also..sounds cheaper than a swithch!!??

Cheaper, and your seat/ignition keys still match.

[72500john]

and might i add the ones for the 550 are half the price of the ones for my bike..i want to say around 28 bucks? give or take.

[bollingball]

andy  I forgot earlier here is the link to HondaMans web site if you go with relay. Makes it easy for the electrically challenged


http://sohc4shop.com/catalog/product_info.php?cPath=23&products_id=46

                                                 Ken

[Danno]

Don't forget the grounds that go to the headlight bucket ear bolts they are often a problem with age

[andymum]

Hi guys n gals update,
wow what a headache that was went through wireing loom all ok earths ok still same issue so rewired onto seperate switches straight from battery works great now lol

now just gota figure out how to slot in a relay rather than a fuse

cheers peeps

[72500john]

like i said... hondaman sells a kit. will be great for your application. and while you are at it take your switch apart and clean it. more is better!!