Author Topic: Rescued a 75-77 CB400F earlier today  (Read 1112 times)

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Z3n

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Rescued a 75-77 CB400F earlier today
« on: June 26, 2009, 11:35:40 PM »
Well, long story short, earlier today I discovered a fellow rider stranded on the side the road, and ended up offering to help with repairing the bike (not charging).  

I'm not familiar with field coil charging setups, but the bike is running completely off the battery, with zero voltage coming from the charging system.  My friend says it's the R/R, but being unfamiliar with these bikes, I figured I was best off posting on a place where the experts would hang out.  The bike has 49k on it, but is actually in excellent shape.  Single owner.  

Should I be looking at replacing the stator?  Just the R/R?  Is there a definitive test I can use to rule out the stator and field coil as being the problem?  I've got the Clymer manual, but it doesn't give a resistance value for the stator, it just says they should be high one way and low the other, and each set of measurements should different by a factor of not less than 10.  How's that for confusing wording?   ???

Thanks for any help :)
« Last Edit: June 26, 2009, 11:43:43 PM by Z3n »

Offline tonycb650

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Re: Rescued a 75-77 CB400F earlier today
« Reply #1 on: June 27, 2009, 05:02:09 AM »
If you have zero volts, I would clean/ check all elec. connections first. I had a bad rotor and r/r and i still had 11 or so volts.
80cb650c 80 cm400

Z3n

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Re: Rescued a 75-77 CB400F earlier today
« Reply #2 on: June 27, 2009, 07:24:38 AM »
If you have zero volts, I would clean/ check all elec. connections first. I had a bad rotor and r/r and i still had 11 or so volts.

Sorry, I shouldn't have said "zero volts".  I meant that I wasn't getting anything out of the charging system.  You jump the bike, rev it to around 3k, pull the jumper cables off, and the voltage at the battery was at 11.4 and dropping.  Reving the bike didn't change the voltage at the battery at all.   

Z3n

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Re: Rescued a 75-77 CB400F earlier today
« Reply #3 on: June 28, 2009, 10:48:44 PM »
Well, messed around with it a bit and discovered that one of the stator windings is shot.  Getting 30/30/6 from the 3 stator wires. 

Now to source a replacement...any advice?  Also, does anyone know what the dimensions and thread pitch is on the rotor puller?  I've got a manual but it's a vintage clymer and doesn't show things that would actually be useful.   :P

technojock

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Re: Rescued a 75-77 CB400F earlier today
« Reply #4 on: June 28, 2009, 11:45:40 PM »
Contact Custom Rewind in Birmingham, Alabama 800-798-7282.  They'll rebuild it to better than new for a reasonable price.

Tony

Z3n

  • Guest
Re: Rescued a 75-77 CB400F earlier today
« Reply #5 on: July 08, 2009, 02:16:19 PM »
I actually found one that is guaranteed to work from a bike shop for 40$. 

Now it's just on to the rotor puller.  I've searched, and it appears that the M18x1.5 is what I need as per this post:http://forums.sohc4.net/index.php?topic=18863.0 but additional confirmation would be welcome :)

Thanks!