cb400 problem

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

Richard tea

LookBehindYou wrote: »

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 ??

She turns over but sounds very weak. After about 1 min trying she will start.

Richard tea

Its gonna be a good old fashioned check for bad connections and like Wonda said it could also be a fuel problem. It will be Monday before I get a chance to have a look. Just from a quick look on the net it could be the started switch, a bad earth, dirty fuel etc.. the list goes on.

LookBehindYou

Joe,
If the starter is turning over good, its a fuel problem.

If the starter is weak, its an electrical problem. Starter relay, Starter brushes, connections, Battery, Reg/Rec.

You can do a quick check on charging, by seeing if the headlight gets brighter when you rev, if so rule that out.

Richard tea

LookBehindYou wrote: »

Joe,
If the starter is turning over good, its a fuel problem.

If the starter is weak, its an electrical problem. Starter relay, Starter brushes, connections, Battery, Reg/Rec.

You can do a quick check on charging, by seeing if the headlight gets brighter when you rev, if so rule that out.

Im off to work in 30 mins. Bike started fine there so ill take it today. The headlight did and has brightened when I rev. Old Yellar wont let me down. She just likes to embarrass me a traffic lights.

Ps. Mick, I sent the old LP off last wed.

Richard tea

Ok I noticed on the way to work a spitting sound from the engine. Reminds me of the sound in my car when the injectors were leaking. The bike didnt cut out at all today so far.

bitburger

had an issue with my bike acting like its battery was ****ed this week, even though it had 12.5v, turned out simply to be corrosion on the terminals not making a good connection. I even had 12.5v when i put the multimeter on the frame and solenoid to rule out a bad battery connection!

Richard tea

bitburger wrote: »

had an issue with my bike acting like its battery was ****ed this week, even though it had 12.5v, turned out simply to be corrosion on the terminals not making a good connection. I even had 12.5v when i put the multimeter on the frame and solenoid to rule out a bad battery connection!

I started going through electrical connections today. The connections coming from the spark plugs had some corrosion alright so I cleaned them up. Next step will be to check fuel delivery system. The spark plugs were quite oily when I removed them.

Richard tea

Ok Electrical connections look ok for now. I must open the starter switch and double check for corrosion there. I picked up some Holts carb cleaner and a bottle of RedX also.

Im going to attach 2 pic's. One is the spark plug. Should it be this oily? It wiped off easy and was not hardened.

And the second pic is 2 rubber hoses coming from the carbs. Is this where I apply the carb cleaner?

Wonda-Boy

Spark plugs should not be covered in oil like that joe, could be valve or ring issues. As for the hoses I cant see from that pic whats going on.

Richard tea

Wonda-Boy wrote: »

Spark plugs should not be covered in oil like that joe, could be valve or ring issues. As for the hoses I cant see from that pic whats going on.

I found out where the holts spray goes anyway ( remove the air filter and spray it in there )

Im studying up on carb removal and cleaning if thats needed. Cheers Gar