Author Topic: Wanted Stator for 1971 CB350K  (Read 193 times)

Offline burcotcb350

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Wanted Stator for 1971 CB350K
« on: July 02, 2018, 11:27:08 PM »
I hope someone can help. I have recently purchased a CB350K twin 1971 which was a runner until it stopped abruptly last Thursday. I am pretty sure the stator has gone as the mechanic who picked me up checked it and said that at 3000rpm there wasn't enough charge going to the battery but it ran fine when connected to a power pack.
I am based in Worcestershire but travel around a lot with work so could collect if someone has a working one they would like to sell.
Otherwise if anyone can suggest where i can get one from other than Ebay I would really appreciate it. When searching I keep coming across a kit from the USA with a higher powered stator and a regulator/rectifier called a "Ricks motorsport high output charging kit" and wondered if anyone has any experience of these as they say it will work with my bike but I am reluctant to shell out around £200 without being completely sure its any good.
Any advice would be greatly appreciated.
Paul

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #1 on: July 03, 2018, 12:39:23 AM »
I have a few but I really need them for my own bikes. I would checkout the stator  electrically as per the Genuine Honda manual (which is in my Dropbox links on here). The real problem may be the rotor, not the stator . The rotor has permanent magnets which can lose magnetism with old age. Also on that model a high power coil is switched in by the headlamp switch at night time. One thing you could do is try modifying the wiring so that the night charge is permanently switched in and see if that helps. Unlike earlier Hondas, you won't 'boil' the battery because the 350K has a solid state 'crowbar'  type regulator, which dumps excess current down to ground. It's a novel device and pretty state of the art for a 1968 design and much more sophisticated than the 'Zener' diode used for the same purpose by the likes of Triumph. It may also be your rectifier .. these are selenium on your bike and prone to failure  (if it's the original one with orange fins). They sometimes smell like bad eggs when they fail.  You could fit a modern 25A silicon rectifier (very cheap.. around £5) ........If you get really stuck I could loan you parts to substitute to track down the problem.

Shop manual... here : CB/CL 250/350K SHOP MANUAL

https://www.dropbox.com/s/8i51vjqqdvllazj/CB350ShopManual.pdf?dl=0
« Last Edit: July 03, 2018, 12:51:57 AM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #2 on: July 03, 2018, 07:48:43 AM »
Paul..reading your other post (it was late last night) ... I would just go though all of the electrics including grounds etc before shelling out on any parts. If it's sudden failure it is unlikely to be weak magnestism in the stator. The alternator can't be 'dead' though if the bike runs with the battery flat or disconnected once jump started. The Honda Shop Manual for the 250/350K is very good on electrics. I do have Haynes manuals and a Clymer manual too but they are at work and I am off for  week so I can't scan them. If the resistances of the stator tally with the manual and also  there is open-circuit or very high resistance (megohms)  between any of the coil wires and the laminated steel frame of the stator I reckon it will be OK. If you don't have access to one I would buy a cheap multimeter but make sure it has a 10A or similar DC current range. I have seen them for less than a tenner that are reasonably good. You can always call me if you get stuck 07151521226.

Cheers Ash
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline burcotcb350

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Re: Wanted Stator for 1971 CB350K
« Reply #3 on: July 03, 2018, 08:44:51 AM »
Hello Ash
Thanks for the swift reply, i really appreciate it. I am away myself now until the end of the week but do have a meter and will have a play at the weekend. I have only had the bike a couple of weeks and only been out on it twice so the issue could have been there when i bought it. The chap i got it from had fitted new regulator, coils, points, plugs, leads and rectifier and gave me the old ones in a box. He also said he fitted a new battery but it does look used and I did notice when i first got the bike that the battery is in sideways packed out with foam and the connections are soldered on which didn't look right ? He also told me that the RH handlebar switch wasn't working properly and the lights didn't come on so he has fitted a separate switch for the lights, but the original kill switch still works and i noticed that you mentioned about the high power coil being operated by the headlamp switch ?. I always ride with lights on so wondered if this might have something to do with it ? The first time I went out I did about 35 miles on it and second time managed about 7 miles before it stopped but did notice the issue with the indicators being really slow. The mechanic who picked it up did put a meter on it and confirmed that the battery was flat and when i held it at about 3000 rpm he said there was a slight increase in the reading but not enough to charge the battery. It also might be nothing but the front brake light doesn't work either and my plan was to get a new RH switch unit anyway ?
Many thanks for your help

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #4 on: July 03, 2018, 10:01:03 AM »
Does your bike have a headlamp switch on the headlamp bowl? If not the bar switch switches the high power coil. Let me know when you are back and we can discuss ...The stators on these bikes are epoxy dipped and run in the oil so are normally quite reliable but the wires to the coils often need replacing. If you put your meter on 10A DC range and connect in series with the +battery lead BUT DON'T operate starter motor ....just kick-start it, you will see either charge or drain from the battery whilst running the engine (a bit like the ammeter on old Brit bikes).

Oh ..forgot to say welcome by the way ... send us some piccies of your bike!


« Last Edit: July 03, 2018, 10:02:53 AM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline MCTID

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Re: Wanted Stator for 1971 CB350K
« Reply #5 on: July 03, 2018, 10:06:39 AM »
I have never had to do it myself, but I have read somewhere that you can get your Stator 'Remagnetized' - which might be a possibility if you cannot find a new one.

Maybe other Forum Members can suggest or recommend a company which will provide this service....or if a Stator from another bike (which are more readily available) can be used instead ?

Good luck....and welcome to the Forum.

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #6 on: July 03, 2018, 06:14:29 PM »
I reckon the previous owner has wired the switch incorrectly and you are not switching in the second coil.

If you trace the yellow and white wires out of the alternator and connect  them together you will force the electrics into night-time charge mode, independent of the switch.

I think it was more the CB450K0 Black Bomber that suffered stator magnetism loss. I don't think  rotor from another model will fit and if it did, the timing marks may be wrong. If your rotor was weak magnetically, one option might be to convert to LED lights. DK Motors  do often sell  good used rotors for around £40 and if you don't want to use eBay just phone them.

Here is the Service Manual link but I have copied the relevant page attached, with the switch circled in red.

https://www.dropbox.com/s/8i51vjqqdvllazj/CB350ShopManual.pdf?dl=0

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“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline burcotcb350

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Re: Wanted Stator for 1971 CB350K
« Reply #7 on: July 05, 2018, 10:29:32 PM »
Thanks Ash, I really appreciate all of the help and advice and thank you for the manual it going to be a great help. The switch is on the bars and the chap I bought it off said he had a problem with the lights not working and didn't have time to source an original switch unit so just fitted an independent switch. The kill switch on the original still works as does the electric starter but until i have a look inside i don't know if he has disconnected the light switch wires or just left them, I will have a look over the weekend. I have seen some original switch units on ebay that look the same but should get a better idea when i take the headlight out have have a look at the connector.
I also think that i am still going to change the battery as the one that's on it is in on its end and packed out with foam plus the connections are soldered on for some reason ?
I will post an update and some pics over the weekend
Many thanks again for the help.

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #8 on: July 06, 2018, 06:06:22 PM »
On the bikes that don't have a switch mounted on the headlamp the switching is done inside the bar switch. You can tell if it's correct as there are two rows of switch contacts inside and one row is used to switch the night time coil in when you turn the lights on. Similar switches fitted to Honda fours don't have that row of extra contacts because those bikes have a 3-phase alternator. The Honda twins have a single phase alternator.
« Last Edit: July 06, 2018, 06:12:30 PM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline burcotcb350

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Re: Wanted Stator for 1971 CB350K
« Reply #9 on: July 10, 2018, 10:00:08 PM »
Thank you again for the help and sorry I haven't been back on but I haven't had chance to have a play with the bike yet due to other jobs and the good weather meaning I am riding rather than repairing. Reading your previous post about joining the yellow and white wires to bypass the switch, could this left like that permanently or is it just to test it ?
I am just thinking if that does turn out to be the problem which i think is very likely after what the previous owner did to the light switch then at least i could still ride it while I source a new switch.   

Offline AshimotoK0

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Re: Wanted Stator for 1971 CB350K
« Reply #10 on: July 10, 2018, 10:14:17 PM »
If you do that you will need to have the headlamp switched  on. otherwise the voltage regulator would need to dump more current than intended. 
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.