Topic: Solenoid Rebuild - How to. Anybody know of one?

[Duanob]

I've tracked down why my starter button doesn't work. I tested the button and it was fine. The solenoid isn't working. I can jump the two large terminals and the starter cranks which is good news. I will test with power on the two smaller wires coming from the solenoid. I wasn't sure how to until I researched on this board. I figured since the starter button is just an on/off switch, jumping the two wires together would be the same continuity test but it sounds like I need to power one wire and ground the other. I'll test tonight but I'm pretty sure my solenoid is bad.

There is some rust on the top of my solenoid and the used ones on EBAY don't look any better so I thought I would try and tear it a part and clean it. Anybody have access to a FAQ or how to page? If not I guess I may put one together but it will be trial and error going in blind. What should I expect opening this thing up?

[steam-powered man]

good luck.  if needed, i have regulator/rectifier/fuse panel and solenoid in the "for sale" section, came off a running 78cb750 bike.  starter worked fine.

[number13]

They can be refreshed pretty easily.
Not much to them, just an electromagnet
and a large copper contact. Give the contacts
a good cleaning and make sure it moves freely.
Give it a shot, if it is already bad you have
nothing to lose!

[Whaleman]

I did mine just for fun. If the solonoid unit is burnt out you need a new one. If it clicks and no contact is made you have a chance. I just carefully took it apart and sanded and polished the contacts. They will look bad when you first see them. Just try to sand flat. Dan

[HawaiiMike]

I bought a new one on E-bay for $9 bucks including shipping.  Forget about rebuilding it!

[Duanob]

Wow a new one for $9? The honda oem ones are around $70+. Funny thing, as I put power directly to the low tension wires the thing kicked the starter. So I guess it just needed a good jolt. Now the starter button works again, for now anyway. If it quits again I pull it out and rebuild it. Thanks the replies.

[Bodi]

rebuilding the contact end is no big deal. I don't have one in front of me but how it comes apart was pretty obvious. The soil end is sealed and not serviceable. you can renew the switch contacts, the threaded studs come out and the inned ends are contacts. There's a copper bar that moves to connect the two stud ends together. The mechanical parts do get gummed up.
If it's really dead you can get a much cheaper new replacement that works fine from any garden equipment shop, it won't mount the same but so what?

[Duanob]

Thanks Bodi, I'll book mark this for the next time it quits working. Good thing I can start the bike with one kick or I might worry about the electric start issues 

[bollingball]

Hondmans book has detailed instructions with good pictures. one for my 51 Chevy also works fine you can get it a NAPA auto parts.

[goaarongo]

I just did this.  The two philips head screws in the top come out, releasing the plastic top cover.  You will have to free the two wires from the metal crimp to allow enough room to slide it off.  Easy.  Then test it by touching the positive and negative wires directly to the battery.  If the solenoid clicks open, you are home free.  I removed the two copper posts from the plastic top. and refinished the connecting points inside.  Then I removed the copper bar from the solenoid itself (by opening up the tabbed washer and removing the circlip).  Mine was pretty bad, so I just turned the bar over and refinished the other side (reinstalled bottom up).  Reassemble, and you are good to go.  I think the whole process took about 45 minutes, and I'm pretty through.  Good as new now.  

[HondaMan]

I've tracked down why my starter button doesn't work. I tested the button and it was fine. The solenoid isn't working. I can jump the two large terminals and the starter cranks which is good news. I will test with power on the two smaller wires coming from the solenoid. I wasn't sure how to until I researched on this board. I figured since the starter button is just an on/off switch, jumping the two wires together would be the same continuity test but it sounds like I need to power one wire and ground the other. I'll test tonight but I'm pretty sure my solenoid is bad.

There is some rust on the top of my solenoid and the used ones on EBAY don't look any better so I thought I would try and tear it a part and clean it. Anybody have access to a FAQ or how to page? If not I guess I may put one together but it will be trial and error going in blind. What should I expect opening this thing up?

Which bike?
If you have a Safety Module, the connections to (or operations of) the Neutral switch and/or the Clutch switch can prevent the solenoid from operating. This can be determined easily by looking at the solenoid's wires: if one of them is GREEN/RED or LIGHT GREEN then your bike has a safety module. The other wire will be YELLOW/RED, which comes from the START switch. If one wire is BLACK, then the solenoid grounds via YELLOW/RED at the handlebars: if not, then it grounds via the safety module and the power comes instead from the handlebars when the switch turns off the headlight, using that power to switch the solenoid.

With the safety module, either the clutch must be pulled in or the wires jumpered, or the Neutral switch must be on, for the module to ground the solenoid.

I have a complete post here somewhere on how to disassemble and rebuild the solenoids: search for it and it should show up, pix and all. 

[SohRon]

Here's a shot of the interior of one of these things. The bar is attached to an armature that extends down into a sealed coil in the base of the solenoid. When power is applied to the coil, it causes the armature to jump (like the voice coil on a speaker) and the bar contacts the two studs protruding from the top of the cover. This diverts raw battery power to the starter motor; the high amperage is what causes the pitting on the bar and contacts.

Although the pitting on this particular solenoid ('69 CL350) looks pretty bad, it actually isn't; running your finger over the pitting reveals it to be very shallow and barely discernible. A little emery work and this will be good for another 41 years.

[Duanob]

Thanks Hondaman. It works for now after putting power directly to the solenoid, it just kicked the starter. Then everything worked after that. Probably just stuck solenoid. It may happen again and I will look up your post for a rebuild. Yes it does have a safety switch (76 cb550K).


SohRon LOL after reading your project post I bet that solenoid looks and works like brand new now!

[SohRon]

after reading your project post I bet that solenoid looks and works like brand new now!

Ha! Actually, that unit is one of five parts I still have from my first bike, so it stays as it is for sentimental reasons (snif!).

You must be thinking of this MSU that I'm preparing for the project!  

Before and after; amazing what a little polish and elbow grease can achieve!

[HondaMan]

after reading your project post I bet that solenoid looks and works like brand new now!

Ha! Actually, that unit is one of five parts I still have from my first bike, so it stays as it is for sentimental reasons (snif!).

You must be thinking of this MSU that I'm preparing for the project! 

Before and after; amazing what a little polish and elbow grease can achieve!

Wow! Maybe I'll take my box of them over to your house. 

[SohRon]

Wow! From you that is a real compliment; thanks, Honda Man. I (who am not worthy) consider it a lucky day when I get a positive reaction from one of the Forum Gods...

Red Scotchbrite impregnated with Hope's Stainless Steel Polish for the staining and initial cleaning, followed by Flitz Polish and some hand buffing really brings up the shine. For the cover, a spritz of Must For Rust on a blue Scotchbrite pad got rid of the rust and some Mother's Back To Black brought it back to life. Some new assembly screws, nuts and washers complete the restoration. Too bad it'll be hidden by a big black rubber band. Here's the completed electrical panel

In my mind I see racks of these things just waiting to be attached to the new bikes going by on the line. It must have been a sight!

[dave500]

ive opened one up before,cleaned the contacts,be carefull ,there isnt much slack in the small wires,it went for a couple of weeks,opened it up again and cleaned it and put a slight bend in the activation direction of the contact bar,went for a couple of weeks so i just used another old one i had,the electro magnet part might be getting soggy giving a feeble pull maybe?its only 37 years old i should complain!

[HondaMan]

Wow! From you that is a real compliment; thanks, Honda Man. I (who am not worthy) consider it a lucky day when I get a positive reaction from one of the Forum Gods...

Red Scotchbrite impregnated with Hope's Stainless Steel Polish for the staining and initial cleaning, followed by Flitz Polish and some hand buffing really brings up the shine. For the cover, a spritz of Must For Rust on a blue Scotchbrite pad got rid of the rust and some Mother's Back To Black brought it back to life. Some new assembly screws, nuts and washers complete the restoration. Too bad it'll be hidden by a big black rubber band. Here's the completed electrical panel

In my mind I see racks of these things just waiting to be attached to the new bikes going by on the line. It must have been a sight!

That's some amazing work! Those look better than my restos of them: I might have to adopt your methods, if my (gnarly) fingers will let me. 

Except for one thing: my restos never include the Safety Module...     

[SohRon]

That's some amazing work!  ...my restos never include the Safety Module...   

Thanks again, HondaMan. You should have seen it before I started the resto (shudder). Here's the backside shot

I bought the original panel off ebay because of the safety unit, so there ya' go on the one man's poison bit. 

Thanks to you for your encouragement and to the OP for his indulgence...