Topic: Will a bike kickstart with a bad rectifier?

[leogriss]

CB350F
My battery was dead so I took it to an Autozone so they can charge it.
Meanwhile, I was thinking myself why not use a car battery to start it.
So I got a battery cable and connected to the bike. white smoke coming out from the left sidecover.
Immediately disconnected the battery cable.
I'm not exactly sure where the smoke was coming from but I assume it's from the rectifier since it was warm?

Do you think I just fried my rectifier!!?
Is it possible to kickstart the bike with bad rectifier ( let's say battery is good)?
What did i doooo!  

[Gordon]

It's impossible to say without more specifics, but my first guess is that you accidentally reversed the polarity between the car battery and the bikes battery cables.  Doing that, even for a split second, will fry the rectifier and melt some wires, causing the smoke you saw. 

A dead rectifier will not keep the bike from running, but the charging system won't work anymore, so it will only run as long as the battery holds up. 

[Gordon]

Look at the block connector that the rectifier plugs into.  Find any melted wires and follow them as far back as the damage occurred.  The green wire will often be melted all the way through the harness up to where it grounds on the backbone near the coils.  Make sure the adjacent wires haven't been damaged, too.

[leogriss]

Look at the block connector that the rectifier plugs into.  Find any melted wires and follow them as far back as the damage occurred.  The green wire will often be melted all the way through the harness up to where it grounds on the backbone near the coils.  Make sure the adjacent wires haven't been damaged, too.

Thank you for the reply.

I'll double check when I get home. Do you know if rectifiers are interchangeable with other models?
Thank you!

[Duke McDukiedook]

What made you think it was OK to hook a car battery up to a motorcycle battery?

How do you know your rectifier was not already fried at that point- You did have a dead battery.

[fmctm1sw]

All these based on the part number search:

31700-333-008  CB350F A MOTORCYCLE, JPN, VIN# CB350F-1000001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB350F1 A MOTORCYCLE, JPN, VIN# CB350F-2000001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K A (76) MOTORCYCLE, JPN, VIN# CB750-2540001 TO CB750-2575894
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K0 A MOTORCYCLE, JPN, VIN# CB750-1000001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K1 A MOTORCYCLE, JPN, VIN# CB750-1044650
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K2 A MOTORCYCLE, JPN, VIN# CB750-2000001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K3 A MOTORCYCLE, JPN, VIN# CB750-2200001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K4 A MOTORCYCLE, JPN, VIN# CB750-2300001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K5 A MOTORCYCLE, JPN, VIN# CB750-2500001
Assembly: BATTERY RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB500K1 A MOTORCYCLE, JPN, VIN# CB500-2000001
Assembly: BATTERY + ELECTRIC P... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB500K2 A MOTORCYCLE, JPN, VIN# CB500-2100001
Assembly: BATTERY + ELECTRIC P... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB400F A MOTORCYCLE, JPN, VIN# CB400F-1000006 TO CB400F-1038492
Assembly: BATTERY + RECTIFIER RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB400F A (76) MOTORCYCLE, JPN, VIN# CB400F-2000001 TO CB400F-2008280
Assembly: BATTERY + RECTIFIER RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB400F A (77) MOTORCYCLE, JPN, VIN# CB400F-2100001 TO CB400F-2104166
Assembly: BATTERY + RECTIFIER RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750F A (77) MOTORCYCLE, JPN, VIN# CB750F-2100011 TO CB750F-2111489
Assembly: BATTERY + REGULATOR RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
Sku  Model Description Req Price     View
31700-333-008  CB750F A (78) MOTORCYCLE, JPN, VIN# CB750F-2200001
Assembly: BATTERY + REGULATOR RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K A (77) MOTORCYCLE, JPN, VIN# CB750-2700009 TO CB750-2729534
Assembly: BATTERY + REGULATOR RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750K A (78) MOTORCYCLE, JPN, VIN# CB750-2800001
Assembly: BATTERY + REGULATOR RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550 A MOTORCYCLE, JPN, VIN# CB550K-1000001
Assembly: FRAME + WIRE HARNESS RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550K A (76) MOTORCYCLE, JPN, VIN# CB550K-1230001
Assembly: FRAME + WIRE HARNESS RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550K1 A MOTORCYCLE, JPN, VIN# CB550K-1200001
Assembly: FRAME + WIRE HARNESS RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750F A MOTORCYCLE, JPN, VIN# CB750F-1000002 TO CB750F-1015054
Assembly: FUSE BOX + REGULATOR... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB750F A (76) MOTORCYCLE, JPN, VIN# CB750F-2000003 TO CB750F-2022317
Assembly: FUSE BOX + REGULATOR... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550F A (77) MOTORCYCLE, JPN, VIN# CB550F-2100001 TO CB550F-2114871
Assembly: LEFT SIDE COVER + EL... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550K A (77) MOTORCYCLE, JPN, VIN# CB550K-2000007 TO CB550K-2015308
Assembly: LEFT SIDE COVER + EL... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550K A (78) MOTORCYCLE, JPN, VIN# CB550K-2100001 TO CB550K-2122082
Assembly: LEFT SIDE COVER + EL... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550F A MOTORCYCLE, JPN, VIN# CB550F-1109886
Assembly: SIDE COVER + BATTERY... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     
31700-333-008  CB550F A (76) MOTORCYCLE, JPN, VIN# CB550F-2000003 TO CB550F-2010866
Assembly: SIDE COVER + BATTERY... RECTIFIER ASSY. (Honda Code 0297341) (SKU: 31700-333-008) 1 $220.62     

[fmctm1sw]

What made you think it was OK to hook a car battery up to a motorcycle battery?

I've done it many times.  My 175 twin too...

[famoussas1]

i noticed on my 550 this winter that previous owner fried the rectifier, or at least fried the ground going up the panel to the coils under the tank. i didnt ride it enough to realize if my battery charged, but i may just buy a rectifier and install it next time i get to ride and see it not charging.

luckily the ground that fried didnt fry anything else after it smoked and burned up..was a fun fix and got to see some of the electrical on the backbone though.

[leogriss]

What made you think it was OK to hook a car battery up to a motorcycle battery?

How do you know your rectifier was not already fried at that point- You did have a dead battery.

I read somewhere here that hooking up a car battery is fine.....  lesson learned! 

[leogriss]

i noticed on my 550 this winter that previous owner fried the rectifier, or at least fried the ground going up the panel to the coils under the tank. i didnt ride it enough to realize if my battery charged, but i may just buy a rectifier and install it next time i get to ride and see it not charging.

luckily the ground that fried didnt fry anything else after it smoked and burned up..was a fun fix and got to see some of the electrical on the backbone though.

Thank you for the list, fmctm1sw.
It should be too bad to find one now!

Okay so I just checked my rectifier with my Ohmmeter.
I'm not getting any number what so ever. I guess I did really burn my rectifier

Do you recommend to start the bike with this messed-up rectifier on as soon as I get my battery charged?(I just want to check if battery was the problem why my bike doesn't start) Or should I wait until I find a new rectifier?
How can you tell if the harness that goes to the rectifier is okay? I might burned the harness too??  

Thank you

[Alan F.]

If you're interested in not spending a ton of money on a rectifier, there are alternatives.

http://forums.sohc4.net/index.php?topic=12465.0

[OldSchool_IsCool]

What made you think it was OK to hook a car battery up to a motorcycle battery?

How do you know your rectifier was not already fried at that point- You did have a dead battery.

I read somewhere here that hooking up a car battery is fine.....  lesson learned! 

Jumping off a car battery is not the problem.  I jumped mine just today.  CROSSING the wires, car battery or M/C battery is instant death to the more sensitive electronic zones, like the rectifier.

[Spanner 1]

Unplug that rectifier BEFORE you put the battery back in.... bike will run on battery only for a short time before headlight goes dim and bike dies with the charging system disconnected and battery not charging........ that said, I have ridden all day with a car battery connected and strapped to the rear carrier on a 750DOHC that wasn't charging ( rotor removed and sent to be re-wound )....!

[Gordon]

Jumping off a car battery is not the problem.  I jumped mine just today.  CROSSING the wires, car battery or M/C battery is instant death to the more sensitive electronic zones, like the rectifier.

+++1!

There is NOTHING wrong with using a 12V car battery to either run or jump-start a 12V motorcycle off of.  The motorcycle will only draw as much current as it needs.  The problem comes when the polarities are reversed, regardless of the type of battery that was being connected.

Don't shy away from jumping your bike from a car in the future, just don't hook it up backwards.  

[TwoTired]

Okay so I just checked my rectifier with my Ohmmeter.
I'm not getting any number what so ever. I guess I did really burn my rectifier

Modern digital ohmmeters inject very small voltages into the circuit being tested.  Diodes need about .6 to .7 V for them to bias into conduction.  That's why most Digital meters have a special function setting for testing diode junctions.  Look for the symbol;   -|>-  .  This setting provides enough voltage to make a good diode conduct in one polarity direction.  Using other ohmmeter settings will make any diode good or bad appear to be open (unless the diode failed by fusing internally, then it will conduct regardless of polarity.)

[MotorFist]

Thanks TwoTired.  Your post just saved me from buying a new rectifier.  I am new to this and never would have known!

[mgbgt89]

Unplug that rectifier BEFORE you put the battery back in.... bike will run on battery only for a short time before headlight goes dim and bike dies with the charging system disconnected and battery not charging........ that said, I have ridden all day with a car battery connected and strapped to the rear carrier on a 750DOHC that wasn't charging ( rotor removed and sent to be re-wound )....!

Awesome.. I love a good story of dedication.

[754]

 Actually.. a 750 battery charged .. yes I know a 350 one is 2/3 size or so...

 ..anyway, a 750 stock battery in a 750 with lights off and brakelites unhooked.. should run about 3 hrs or longer in 60 F  or wamer weather.. with no charging ocurring..

[terrified_camel]

   Jump starting is a good way to ruin your rectifier diodes.  You are forcing current in backwards.  You should disconnect the battery while charging it.

  Also, diodes go bad, then work, then go bad, they are like a loose wire, they can be impossible to diagnose because they work, a little while, then don't work, then work, then don't work, then work, then finally will stop working....sort of.

[Spanner 1]

Not quite right, Terrified........ you could connect a battery the size of a house to your bike with no ill effects once it was 12v and you connected it with proper polarity...... no current or voltage 'forced' anywhere.  The starter motor would only demand the exact same current as it would from the bike battery, as would the lights and ignition...... personally, I've never seen a rectifier go open-circuit or short-out and then work again?..... welcome to the Forum.....

[gerry113377]

I had rectifier/charging issues and it turn out to be cut wires in the harness.  The harness was hanging down rubbing against the chain on the front sprocket.  You might want to check that.  Check resistance on the rectifier and see if you get voltage spikes if you rev the engine.  Also check resistance on the 3 yellow wires from your alternator.  Hope this helps.

[Gordon]

  Jump starting is a good way to ruin your rectifier diodes.  You are forcing current in backwards.  

And the old wive's tale lives on.  

[Bob750]

Whatever you do, don't let the smoke out of any more electrical parts... Not enough smoke inside means not enough smoke to work properly...  Ahem.

[Spanner 1]

How to put the smoke in electrical stuff is a Gov'mint secret... I think no-one knows, it's been traced back to some yak herder in Mongolia, but he turned out to be a fake, just another false lead, oh well......

[scottly]

Some of the best smoke packers used to be in Sunnyvale, CA. However, no one, to my knowledge, has ever come up with a way to replace OEM smoke, once it has been let out.