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Rectifier question??

CB750Todd

CB750 Enthusiast
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Ok..my '75 has charging issues, battery won't stay charged,headlight dim, blinkers won't blink etc.... So I pull the voltage regulator off my '72 and try it but no improvement...then I go to pull off the rectifier and notice they are different. The rectifier on '75 seems to be stock like it shows in manual but the '72 rectifier seems to be aftermarket, looks like solid state type or something...its a sealed unit. I'm assuming it is aftermarket,it has S4T-05 on it...anyway,about to hook it up to see if that fixes my problem with charging. The last time the '72 was running it was charging good.... If anyone knows anything about this rectifier please give me your input...thanks
 
IMAG0324.jpgHere is a pic of the rectifier in question
 
I think it is off of a CB400f. I have never dealt with one. What is your battery voltage at idle and at about 3000rpm. At idle it more than likely will be less than 12.5 volts but at 3000 it should be around 13 to 13.5 volts. These have very bad charging systems at low rpm. If you have a shop manual go through the charging system checks. Bad connections are another common problem on the 750 as far as the charging system.
 
i checked voltage and it does seem to be charging ok...3000-4000 rpms gives me about 13-14 volts...blinker problem was the flasher,headlight still has problems but there are a few splices in the headlight bucket that I need to go through... I ended up keeping the stock rectifier on it and it does seem to all be working... thanks for the info Digger
 
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