cb400 problem

Richard tea

Went to start the bike this morning and she seemed very low on battery power. I noticed the engine kill switch was engaged so I switched it back. Bike still didn't want to start. I held in the clutch and gave her a roll and she started. So off I went on my 40 mile commute with no problems. Finished work today and the bike still seemed a little hesitant to start. When I did get going there was no problems until I literally pulled into my driveway and the bike conked out??? I loaned out my battery charger and wont have it back until tomorrow. A neighbor pointed towards a possible battery/ rectifier problem.?

I think the fact that the engine kill switch was pressed means some kids where sitting on the bike and twisting the accelerator & flooding the engine. Could this be my problem- flooded carbs/engine??? I did commute 80 miles since the trouble this morning so im not sure its that.

Wonda-Boy

Was the bike switched off by the kill switch before? This leaves the lights on, on alot of bikes. So the battery is probably on its last legs....and the commute charged it but not enough.

Richard tea

Ive never used the kill switch to turn off the bike. One of the kids ( not my own ) must have been at it. Ill plug the battery into the charger tomorrow and see what she reads. To be honest I never thought the battery was 100% from the start.

Wonda-Boy

Hondas are prone to the reg/rec giving trouble.....could very well be that.

bitburger

can you get your hands on a multimetre??

if you set it to the 200 beside the setting on the picture you can measure volts in tens. when the engine is running touch the red off the pos and the black off neg and see what your getting? it generally needs around 13v+ to be charging the battery, if you are getting the voltage it is more than likely the battery, if the voltage is 12 or below then there is no power going back into the battery, probabaly best to test with another battery, a car battery will work with jump leads but if the battery is in a car do not start the car! again test the voltage with the bike running and see what you get.

Richard tea

bitburger wrote: »

can you get your hands on a multimetre??

if you set it to the 200 beside the setting on the picture you can measure volts in tens. when the engine is running touch the red off the pos and the black off neg and see what your getting? it generally needs around 13v+ to be charging the battery, if you are getting the voltage it is more than likely the battery, if the voltage is 12 or below then there is no power going back into the battery, probabaly best to test with another battery, a car battery will work with jump leads but if the battery is in a car do not start the car! again test the voltage with the bike running and see what you get.

Fair play Bitburger. Ill give it a blast tomorrow evening. Sounds simple enough.

Please Kill Me

Wonda-Boy wrote: »

Hondas are prone to the reg/rec giving trouble.....could very well be that.

Yep, the OH's Super Four had to have the rectifier and battery changed not long after we got it. Apparently, it's a common fault.

@ Joe - I have a charger here if you're stuck, you know where I am, just stroll up and give us a knock.

Richard tea

Please Kill Me wrote: »

Yep, the OH's Super Four had to have the rectifier and battery changed not long after we got it. Apparently, it's a common fault.

@ Joe - I have a charger here if you're stuck, you know where I am, just stroll up and give us a knock.

Cheers for the offer. I have to meet up with the bro tomorrow anyway. He borrowed the charger for a car.

Bikerguy

btw i had similar problem with my cb400 --> it was burned regulator - the value i was geting were --> 11,5v when not charning and over 13v when reving going slightly up. i went to garage and they fixed the issue the same day for 140€ .....

Wonda-Boy

You will get a reg/rec in city spares/costellos cheap enough.

Richard tea

Ok I got the readings from the multimeter which are as follows

Neutral, 1200 RPM = 12.6v
3200 RPM = 13.8v


When I connected the battery to the charger it started on 50% of a charge. So I guess the battery was not getting a charge when driving???

What do you lads think. Are there any other tricks to try?

Ill charge up the battery and see how she goes.

If it is the rectifier/regulator, Where would one find such a gizmo on the bike?

Wonda-Boy

The reg/rec is black and only the size of a wallet and sits usually under the saddle.

Richard tea

Wonda-Boy wrote: »

The reg/rec is black and only the size of a wallet and sits usually under the saddle.

Nice one. Think I know it now. I just copped something after reading the manual for the battery. Whenever I connected the charger to the battery before it would start off at 75% which I took for the battery having a full 75% charge. But this is actually 75% of the remaining battery. So the battery could be bolloxed. Ill have a better idea tomorrow after an overnight charge. Ive located city spares so im sorted if I need a new R/R

KamiKazi

Richard tea wrote: »

Nice one. Think I know it now. I just copped something after reading the manual for the battery. Whenever I connected the charger to the battery before it would start off at 75% which I took for the battery having a full 75% charge. But this is actually 75% of the remaining battery. So the battery could be bolloxed. Ill have a better idea tomorrow after an overnight charge. Ive located city spares so im sorted if I need a new R/R

IIRC it's behind the black triangular panel on the left side of the bike.

I had the same problem with I had my CB400. New RR & battery sorted it. Bout the only thing that goes wrong with older Hondas to be fair.

Richard tea

KamiKazi wrote: »

IIRC it's behind the black triangular panel on the left side of the bike.

I had the same problem with I had my CB400. New RR & battery sorted it. Bout the only thing that goes wrong with older Hondas to be fair.

Thanks Kam. It can wait till tomorrow. I have the feet up now:) At this stage im thinking its both battery and RR acting up. I can prob get a battery for 60 quid and hopefully a RR for around 30 second hand.

Is the RR a simple plug in device or is there soldering involved?

bitburger

that doesnt condemn the reg/rec it should jump a few more volts with more rpm, is it a sealed battery?

KamiKazi

Richard tea wrote: »

Thanks Kam. It can wait till tomorrow. I have the feet up now:) At this stage im thinking its both battery and RR acting up. I can prob get a battery for 60 quid and hopefully a RR for around 30 second hand.

Is the RR a simple plug in device or is there soldering involved?

Simple connector unless it's been hacked apart previously.

Richard tea

Battery is a Bosch M6. Is says ''Do not open'' on the battery so I assume that means its sealed? The Volts did rise when I increased the rpm. Are you saying that the RR could be fine and its just the battery?

gctest50

They'd just plug in
- be careful though
- bolt the new one in place first before testing it
- some depend on the metal they are bolted to to get rid of heat
- some seem to have no proper overheat protection so they just get hot and run away with themselves

gctest50

Richard tea wrote: »

But this is actually 75% of the remaining battery. So the battery could be bolloxed. Ill have a better idea tomorrow after an overnight charge. Ive located city spares so im sorted if I need a new R/R

You'd need to poke it with a discharge tester ( kinds like attached photo )

- it just put a load across the battery and the weak cells will show up

- you need a tester intended for bike batteries instead of submarine batteries

need to be a bit careful doing this - battery can explode and cover you in nice warm acid

Wonda-Boy

Whatever you do dont buy a battery on its own....as if it is the reg/rec it will bollocks the new battery. If anything get the reg/rec 1st and then charge the battery.....or both together.

Richard tea

gctest50 wrote: »

You'd need to poke it with a discharge tester ( kinds like attached photo )

- it just put a load across the battery and the weak cells will show up

- you need a tester intended for bike batteries instead of submarine batteries

need to be a bit careful doing this - battery can explode and cover you in nice warm acid

I think ill give that a miss. Like wonda said, ill just get a new battery and RR. At least ill know then that they are 100%

bitburger

Richard tea wrote: »

Battery is a Bosch M6. Is says ''Do not open'' on the battery so I assume that means its sealed? The Volts did rise when I increased the rpm. Are you saying that the RR could be fine and its just the battery?

could well be, if the battery is toast it wont hurt to get a new one and see what happens, yeah do not opens means "sealed" ive taken the caps off of dead ones before and added distilled water as you would with a traditional battery and its improved the health of the battery, it is only really a temporary measure though

Richard tea

Ok so I charged the battery overnight and stuck her in today. She started with no problems. Volts reading was 12.4 on idle?

Wonda-Boy

Thats grand joke, but will it sustain the charge. If the reg/rec is fooked you will be back to square one as the battery is not getting charged while driving.

Richard tea

Wonda-Boy wrote: »

Thats grand joke, but will it sustain the charge. If the reg/rec is fooked you will be back to square one as the battery is not getting charged while driving.

I know but it will be Friday before I get to use the bike again. Ive decided if it doesnt hold a charge my first step is to hit city spares for a RR.

KamiKazi

Richard tea wrote: »

Ok so I charged the battery overnight and stuck her in today. She started with no problems. Volts reading was 12.4 on idle?

Whats it reading at 3-4k rpm?

Richard tea

KamiKazi wrote: »

Whats it reading at 3-4k rpm?

From a reading I done yesterday i was getting 3200 RPM = 13.8v which says to me it is giving a charge. Is that correct?

Ps, I removed the side panels today and didn't see a RR so it is under the fuel tank.

bitburger

seems like its charging to me, it can give upto 15v,

Wonda-Boy

13.8v is perfect Joe. So if its putting that out and still goosed it has to be the RR.

bitburger

thats when the bikes running though, so 13.8 says charging to me, forgot to ask you to check the voltage of the battery without the bike running, preferably after sitting overnight, if theres a voltage drop below 12v your battery is at fault,

Richard tea

Thanks lads. Wont get a chance to look at the bike until late this evening. Ill report back then.

Wossack

have a gander:

http://www.electrosport.com/technical-resources/library/diagnosis/pdf/fault-finding-diagram.pdf

If it is the r/r goosed, I'd be trying to get a mosfet type unit to replace the one thats there now (which is most likely a shunt type - which are very prone to burning out).

Personally wouldnt buy a secondhand shunt one anyway - I'd be a little concerned about it just happening again, and taking a new battery with it (again)

CJhaughey

Wossack wrote: »

have a gander:

http://www.electrosport.com/technical-resources/library/diagnosis/pdf/fault-finding-diagram.pdf

If it is the r/r goosed, I'd be trying to get a mosfet type unit to replace the one thats there now (which is most likely a shunt type - which are very prone to burning out).

Personally wouldnt buy a secondhand shunt one anyway - I'd be a little concerned about it just happening again, and taking a new battery with it (again)

Easy enough to convert over to the newer type Mosfet units, easternbeaver.com sell the plugs for the FH series reg-recs as fitted to Yam R1's and late model 'Blades.
I have one to fit but need to cut the fins down as they are massive on the FH-011 the FH020 is
much more compact.

Shindengen codes are FH for Mosfet type regs and SH for the old shunt type( Mosfet is still shunt but switched differently)

galwaytt

....tbh 12.4v at idle is too low. It should hover at/above that with bike off, otherwise battery is fubar'd.

13.8v - 14.4v (low/higher) revs would be ideal no's to see.

Oh, and, you mentioned you loaned your charge to your brother for a car - is it a car charger then ? If so, that'll fubar your bike battery in no time. Car chargers are too powerful for bike batteries. Charge at no more than 10% of the battery's capacity - so ideally your looking for a 1000mA - 1800mA charger for a bike like the CB. A car charger will boil & wreck a small bike battery.

Richard tea

galwaytt wrote: »

....tbh 12.4v at idle is too low. It should hover at/above that with bike off, otherwise battery is fubar'd.

13.8v - 14.4v (low/higher) revs would be ideal no's to see.

Oh, and, you mentioned you loaned your charge to your brother for a car - is it a car charger then ? If so, that'll fubar your bike battery in no time. Car chargers are too powerful for bike batteries. Charge at no more than 10% of the battery's capacity - so ideally your looking for a 1000mA - 1800mA charger for a bike like the CB. A car charger will boil & wreck a small bike battery.

Just home and havent had time to look at the bike yet. Prob wont get a chance until friday morning. Yeah ill have to check the voltage again at different revs,

Its a bike charger alright so thats fine. Not sure if bro even used it for the car.

Thanks for the info lads. Ill do more checks and report back asap.

Richard tea

ok lads I got some readings which leads me to believe the RR is fine.

Gear in Neutral for all readings.

Idle = 12.3 v

2000 rpm = 14.1 v

3000 rpm = 13.8 v

4000 rpm = 13.7 v

5000 rpm = 13.6 v

Is it normal for the volts to drop with rpm increase?

Today was the first time I started the bike in 5 days and she started first attempt. If you agree that the RR seem ok with those readings I think ill put the problem down to kids hanging out of the accelerator that caused the problem.

bitburger

seems ok to me, ive actually got to put the mm onto my own cb500 tomorrow as i was trying to revive a dead battery which has worked so far, from what i gather the 2 bikes share the same rr so the readings will in theory be similar.

will post my results for comparison, should be similar, my rr works.

Bikerguy

Richard tea wrote: »

ok lads I got some readings which leads me to believe the RR is fine.

Gear in Neutral for all readings.

Idle = 12.3 v

2000 rpm = 14.1 v

3000 rpm = 13.8 v

4000 rpm = 13.7 v

5000 rpm = 13.6 v

Is it normal for the volts to drop with rpm increase?

Today was the first time I started the bike in 5 days and she started first attempt. If you agree that the RR seem ok with those readings I think ill put the problem down to kids hanging out of the accelerator that caused the problem.

the voltage should go up with higher RPM... but they looks very healthy anyway.

Richard tea

Just took the battery off charge and I get a reading of 13.2 v. Ill leave the battery out of the bike overnight and take a reading tomorrow.

bitburger

11.8 at my bike cold thismorning, about 12.2 at idle, 13-14v at higher rpm, after a few minutes i was getting 13ish at idle,


usually a dead RR wont charge the bike atall and voltage will drop, ive also seen them going the other way though and sending unregulated power into the battery, which led to a blown up battery, i could be wrong but i dont think they can fail in any other way.

Richard tea

bitburger wrote: »

11.8 at my bike cold thismorning, about 12.2 at idle, 13-14v at higher rpm, after a few minutes i was getting 13ish at idle,


usually a dead RR wont charge the bike atall and voltage will drop, ive also seen them going the other way though and sending unregulated power into the battery, which led to a blown up battery, i could be wrong but i dont think they can fail in any other way.

It looks like ill just use the bike until the problem re-appears, if it does at all. Good job I stuck with C&N for insurance with breakdown cover;)

bitburger

make sure you have your policy number at the roadside, they wouldnt collect me recently without it!

Soundman

bitburger wrote: »

make sure you have your policy number at the roadside, they wouldnt collect me recently without it!

Really? I had to use the breakdown service once before and was able to get sorted without the policy number. Admittedly I had to answer a ton of questions to make sure it was me, but I got sorted.

Richard tea

Richard tea wrote: »

Just took the battery off charge and I get a reading of 13.2 v. Ill leave the battery out of the bike overnight and take a reading tomorrow.

So I just took a reading and got 12.9 v. Thats about 19 hours since I took it off charge.

Richard tea

Unfortunately im out the door soon and dont have time to investigate this. This seems like it could be the cause of my problem. Starter motor issue + fuse. The chap I bought the bike off did mention he replaced the starter motor.

Richard tea

Unfortunately this problem reared its ugly head again yesterday. The bike cut out about 3 times yesterday on my commute to and from work. I have noticed something that might give a better description of the problem.

I took the bike out the front garden and started it without any issues. I left it running for about 3 minutes and then knocked it off. An hour later i went to start the bike but there was barley a kick out of the starter switch. After about 2 minutes of trying she eventually started and i made off for work. Just as I got to a set of traffic lights at work & had the bike in first gear and the bike died. I got it onto the path and once again after about 2 minutes of trying she started again.

I had the same problem when I went to start the bike after work but got her going anyway. The bike died 2 more time on the way home. Both times are when the bike is stopped at lights. Even when im just about to come to a stop I notice that she sounds like she is going to die.

Any thoughts?

Wossack - Can you expand on that mosfet type R/R. Where to purchase & with what components?

Wonda-Boy

Sounds like the fuel is not getting into the engine all the time maybe the fuel pump Joe? As you already got a new R/R did you not.

Richard tea

Wonda-Boy wrote: »

Sounds like the fuel is not getting into the engine all the time maybe the fuel pump Joe? As you already got a new R/R did you not.

I didnt get a new r/r in the end. I thought the problem sorted itself out:rolleyes:

I started the bike this morning and she started first time. I have the battery charging at the mo because i plan on commuting to work tomorrow on it.

I think this is gonna take a good strip down and check all electric & fuel connections:(

LookBehindYou

Bad connections are most probable cause. I say that because it does start eventually.
Check fuel supply also.

Joe, Is the starter turning over when you hit the button, or is it acase of turning over ok but not firing ??

Wossack

not purchased a mosfet rr, so I'd need to research em a bit. Just know that some are used on yams, and are typically interchangable (same plug connection and all afaik) - no other components needed