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SOHC Honda 750


20thGix

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Does anyone have any experience with an older SOHC Honda 750? I am trying to get the charging system to work and im not having to much luck.

I checked continuaty on the field coil and got 7 ohms(within spec). Checked stator coil and got <=1 ohm (.2ohms is what the book says but my meter starts at 1ohm). The bike is a 72 CL450 but i have a 76 750 motor. I had a taken of the original rectifier and regulator and hooked up a one piece reg/rec for a 750 as per this diagram. http://www.thechopperunderground.com/forum...showtopic=37758

here is what i got with my volt meter.

12volt on red/white wire to reg. ingition off

12volt on black from reg. to ignition with key on

12.4 on white wire from stator

about 12 on + batt. terminal @ idle

Then about 12.5 on + batt. terminal at a higher RPM (no tach) it was definalty a few thousand RPM

And one more thing i checked, the voltage on one yellow coming from the stator and it checked about 6.5 volts if that means anything. could i be getting a voltage leak from my field coil or stator into the motor oil and grounding back into the engine? Eletrical is not my favorite thing to mess with. Any help would be greatly appreciated!

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Well went back to the old mechanical regulator and rectifier after getting like 50volts going back to my battery with the electronic one. After hooking up the old original stuff i was still getting 30+ volts. I opened up the regulator and turned out the screw that adjust the voltage but was still getting somewhere around 20ish volts. Im going to take a guess and say that i need a new regulator. If anyone else has any ideas feel free to throw your 2 cents in.

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You didn't say which model and year of CB750 engine.

But I'll toss in the basic CB750 service manual.

Part 1 http://pdftown.net/4/CB750_1.pdf

Part 2 http://pdftown.net/4/CB750_2.pdf

Part 3 http://pdftown.net/4/CB750_3.pdf

Part 4 http://pdftown.net/4/CB750_4.pdf

Part 5 http://pdftown.net/4/CB750_5.pdf

Part 6 http://pdftown.net/4/CB750_6.pdf

Edited by ReconRat
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I'm a little rusty with my electrical since I haven't been working on too many bikes since I quit the shop a few years ago, this would be a fun thing to poke around on though. Maybe we can get together sometime and I'll see if I can find anything.

Sounds good man! Im going to tinker with it some more this week and see how far i can get with it. Will let you know if i need a new set of eye's on it.

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I'm a little rusty with my electrical since I haven't been working on too many bikes since I quit the shop a few years ago, this would be a fun thing to poke around on though. Maybe we can get together sometime and I'll see if I can find anything.[/quote

If your still willing to take a look i would be more than greatful. I have exhausted my electrical fixin capabilities. Not that i had much in the first place. I think i need to get a new regulator and rectifier but i dont just want to buy parts / throw money at it when its might be something simple that i have over looked.

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And one more thing i checked, the voltage on one yellow coming from the stator and it checked about 6.5 volts if that means anything.

That measurement is leading you down the wrong path.

What you are reading is an AC voltage from the alternator.

With the meter on a DC scale, this will not give you a good reading.

Disconnect the 5 wire plug from the reg/rect.

Measure on an AC scale from yellow wire to yellow wire you should see something like 75 AC volts which will climb as the rpm's go up.

This is normal, Replace the 5 wire plug from the reg/rect.

Alternator is good, move on to the next thing.

All I can say past this is read the manual.

Good luck!

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If your still willing to take a look i would be more than greatful. I have exhausted my electrical fixin capabilities. Not that i had much in the first place. I think i need to get a new regulator and rectifier but i dont just want to buy parts / throw money at it when its might be something simple that i have over looked.

I'd be up for it, I havne't checked this thread lately so I hope my response isn't too delayed. I'm busy tonight and possibly tomorrow. This week I should definitely have a chance though.

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