Topic: 400f NOT the normal charge problem.

[400f newbie]

hi everyone. i bought a 1978 400f2 last year and have tinkered (improved ) with it with a lot of help from this forum.
  i have been riding the bike with no problems except i was not happy with the lights..i replaced the headlight with a 7 inch h4 unit and fitted 2 relays. i decided to change all the other bulbs to leds to compensate for the 55/65 h4.
  i have been enjoying the bike since i done this a few months ago.
  i live in the countryside and only use the bike to enjoy our scenic roads.my wife keeps me on a short leash so my trips are 30 miles or less.
 last week a couple of instrument bulbs blew,so i checked my charging system.these are my results.
ign off. 12.7   
no lights  1100=13.7    2000=16.3  3000=16.1  4000=15.5
               5000=15.6   6000=15.7    7000=16.0  8000=16.0
with lights. 1100=13.2  2000=12.7  3000=13.6  4000=15.5.
               5000=16.0  6000=15-8   7000=15.4   8000=15.3
 my battery did not seem to have boiled or need to be topped up.
 i  do not have an ammeter for further tests.
 parts are hard to find here in ireland .  i usually order from dss.
 the only other change to the electrics are piranha ignition (newtronic) possibly 5 to 10 year old.
 any advice appriciated
     ray

[grcamna2]

It could be a problem w/ the Voltage Regulator..,but the first thing I think you should do is to clean all the ground wires and rectifier grounds to the frame and clean up all your battery to frame connections so you have shiny metal to metal contact on your connections..,then go back & re-test your readings.the charging system may be overcharging to compensate for too much electrical draw or a bad connection giving the voltage regulator the same message(low current)and it's telling your system to charge more. Either way clean electrical connections will be your best ally.I'd also clean the handlebar switch contacts..take them apart and make sure your headlight switch contacts are clean so they won't reduce voltage to your headlight circuits.
 I think that may solve it..or get you closer to finding if your voltage regulater is acting up, clean all the connections to the engine & stator too.

[400f newbie]

thanks for the quick reply grcamma2
i have already checked most of the connections and they were squeaky clean.i do not have any history of the bike but the bike seems to have been restored with the frame powder coated sometime in the past decade.i have a suspicion that a po tried to improve the regulator.
.ray.

[grcamna2]

Ray,
   If she's been powder coated check the battery ground strap to the engine mount bolt and then you may have to scrape off the coating between the engine block itself and the inside of the frame mount mount where the engine block bolts down inside it.I imagine it would be easier if you were to get a star lock washer and clamp it down between the engine block & the frame where the motor mount bolt holds tight to the negative battery ground strap.Ray,that powder coating is notorious for keeping the engine from grounding correctly in that spot...,w/o that clean your voltage regulator will get a false"low voltage" reading & pump more volts out.

[HondanutRider]

I have a CB350F that I believe has a similar regulator/charging system.  The Honda shop manual for these models covers the regulator adjustments quite well, and its a pretty simple mater to remove and inspect its points and adjust their gap.  Mine looked to be a bit "fiddled" and the gap was a bit off, so I adjusted it to spec.  My voltages are a bit lower than what you read, but still over 15.

[400f newbie]

grcamna2.....thanks for your advice.  i have gone over all the frame and engine earths and all contacts look like new..
the vr looks like it was never touched by the po so apoligies for taking his/her name in vain.
hondanutrider....i have the vr ready to put on the dining room table and bend the adjusting arm.pity it does not have the adjusting screw like the 500 vr.
ray.

[Deltarider]

Have you checked with an analogue V-meter? Digital meters sometimes produce funny results with engines running. Don't know why.

[400f newbie]

delta.....the reason i checked the vr was because of rev leds blowing so it was no surprise to see high voltage.
so who is the giant above the bike.
ray.

[TwoTired]

Its clear the regulator is not telling the alternator to back off.

Could be the adjustment, could be the lies being told to the regulator.

First eliminate lies.

Determine the voltage drop between the Battery POS terminal the Vreg Black wire terminal.  Voltage probe at each point with all the electrical devices on.  The added relays can easily mask a power distribution problem.

In the same way, probe the Battery NEG and the Green wire connection to the Vreg.  The sum of these two reading is the amount of lying going on to the regulator.
If the sum is more than .5V, you have to go after the liars in the distribution; switches, connectors, fuse terminals, etc.

Then, if the Vreg is getting the correct info about battery status, then it is time to tweak the Vreg for proper sensitivity to the voltage reported to it, and turn the adj. screw so the battery can't ever charge above 14.5V.

I'd do the vreg point contact inspection, and adjust the gaps per Honda manual first, though.  But, if you don't mind adjusting the vreg twice, you can tweak first and inspect later.

Cheers,

[400f newbie]

tt..i have just  came back into the house after refitting the vr.the good news is i am the right track.bad news is i overadjusted.
problem is the 400 vr has no screw for adjusting like the 500 vr.
you have to bend the arm which is hit or miss.
have to leave it till tomorrow to keep her majesty happy..
ray

[TwoTired]

tt..i have just  came back into the house after refitting the vr.the good news is i am the right track.bad news is i overadjusted.
problem is the 400 vr has no screw for adjusting like the 500 vr.

Odd.  My Haynes manual shows the same vreg as used in the all the other SOHC4s.  The screw doesn't change the points geometry, it changes the spring pressure for the points arm.

Do you have any sort of shop manual?

[400f newbie]

tt...i have a haynes manual dated 1976 (it also looks that old).
    it shows no picture or diagram of the vr but does state that some models are not adjustable.
   i downloaded the 400 manual from this site and it shows the vr without the adj screw.  it shows how to bend the adj arm to change the charge rate. a bit hit or miss but i will plod on.
ray.

[400f newbie]

..

[HondanutRider]

Ray, your VR looks the same as on my CB350F.  I found the lower points arm to be "marred" from a PO work I'm sure, and that gap was was more than the Honda manual spec.  I tweeked it back a bit and brought it close to the spec, and my charging voltage seemed to reduce to a more acceptable level, although it wasn't quite as high as your report.

[400f newbie]

hondanutrider.....
i ordered a vr from oregon two mins ago.set armature gap,point gap but the adj arm is hard to bend in small increments. the vr is going on and off like a yo yo.not happy with the results so far.
at least i now know the vr is the problem.all the screws looked as if they were never disturbed but it was obvious the the internals were fooked with.
ray

[Deltarider]

so who is the giant above the bike. 

Aaaaaahhh... thought nobody would ever ask.
I'll tell you, but first let's see if there's somebody in this forum, who knows.
So, who is the man and in what country do we find his statue?
Oops, almost forgot. The bike is mine. The day before I took this picture (illegally!) I rode > 200 kilometers in one day (Thank you, thank you, 400F for offering me the opportunity). I must confess I handed my bags to friends who did the same stretch by car.
And the winner is.....

[400f newbie]

boer war general ???location holland
getting warm
ray

[Deltarider]

boer war general  ???location holland 
getting warm 

Ah, I might as well tell you. It's Livingstone, Doctor Livingstone for you. He put Africa on the map so to speak. The statue is at Victoria Falls at the Zimbabwe/Zambia border. Wardens wouldn't admit my bike in the park, but I wanted that picture so badly, so I trespassed and sneeked in.

[400f newbie]

I JUST WANT TO THANK ALL THE MEMBERS WHO REPLIED TO MY VR PROBLEM.i had the vr off the bike like a whores knickers on a friday night
no matter what adjustment i made ,the voltage was either too high or too low.you 500 and 750 owners are very lucky to be able to adj your vr with a screw.
my german sheapard (tosca) must have sensed the black clouds around the vr on the kitchen table because when i was distracted ,she removed thr vr and buried it in the garden.now when i test the vr it flatlines(ie #$%*ed).
        i received my new oregon vr and fitted it today.bliss and perfect harmony have decended upon me.the big bonus is the adj screw on the outside of the vr.s