Author Topic: 1980 CB125S seized piston  (Read 9030 times)

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Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #50 on: May 13, 2020, 03:03:32 PM »
I definitely agree with using OEM parts. Speaking of that, I wonder if it'd be sketchy to clean up and use the original piston over the chinese one if I go with the kit?

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #51 on: May 13, 2020, 03:16:30 PM »
I definitely agree with using OEM parts. Speaking of that, I wonder if it'd be sketchy to clean up and use the original piston over the chinese one if I go with the kit?

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The least expensive way to go(simplest)would be to buy and install that China piston/cyl. kit item #272978147073.
The kit comes complete(the cylinder has already been machined to fit that China piston and rings) with the entire top-end set you'll need less the cylinder head,etc. for $89.90 something.
I have a lot to learn on the computer but hope you can see the listing using the item # I posted.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #52 on: May 13, 2020, 03:32:02 PM »
Yep I see the one that you're talking about! That's what I'll do then.

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Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #53 on: May 13, 2020, 03:33:13 PM »
Did you happen to see the pic I posted of the cam chain tensioner arm and the crack in it?

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #54 on: May 13, 2020, 03:37:05 PM »
Did you happen to see the pic I posted of the cam chain tensioner arm and the crack in it?

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Yes,I have a good used one if you need it.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #55 on: May 13, 2020, 04:18:55 PM »
I probably will. All the sellers on eBay have month or longer shipping times. Think jb weld would be a bad idea on that crack? Or just leaving it be? It stops right at the metal bushing in there.

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #56 on: May 13, 2020, 04:23:53 PM »
I probably will. All the sellers on eBay have month or longer shipping times. Think jb weld would be a bad idea on that crack? Or just leaving it be? It stops right at the metal bushing in there.

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JB Weld will never stick and hold inside on that part as it's a rubber part impregnated with oil also.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #57 on: May 13, 2020, 04:48:19 PM »
Oh that's rubber? I thought it was plastic. That probably explains a few things haha

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #58 on: May 13, 2020, 05:21:00 PM »
Oh that's rubber? I thought it was plastic. That probably explains a few things haha

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They manufacture it with a type of friction resistant rubber material and a piece of springy steel at the core.The rubber hardens over time.
I could sell this used one to you for $15 and the wiring harness for $15 plus shipping.Did you get the rotor removed ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #59 on: May 13, 2020, 07:20:36 PM »
Oh that's rubber? I thought it was plastic. That probably explains a few things haha

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They manufacture it with a type of friction resistant rubber material and a piece of springy steel at the core.The rubber hardens over time.
I could sell this used one to you for $15 and the wiring harness for $15 plus shipping.Did you get the rotor removed ?
That sounds great! PM me and we'll sort out the payment all that jazz. Also yeah the axle trick worked perfectly. It's the same thread and pitch actually! Such a useful little hack

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #60 on: May 13, 2020, 08:53:51 PM »
Pielz,
I'll hold-off on sending the parts until you tell me and then get them out to you directly.I do have a couple other parts,let me know what if anything I can help you with.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline WhyNot2

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Re: 1980 CB125S seized piston
« Reply #61 on: May 14, 2020, 03:52:50 AM »
Looks like you're getting this little 125 going purdy good.

Glad the kicker pedal turned out well for you.

I would have bought that cylinder kit if it would have fit my 100.

All I did with this little 100 i got was to slap it together and play with it in the back yard so far.

Good luck and have fun once it's finished.

I'll be watching
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #62 on: May 14, 2020, 08:30:40 AM »
Thanks! Grcamna2 has been a big help and I'm hugely appreciative of that. There's not nearly as much love for these bikes online as our 750s so sourcing information about random things can be difficult.

I actually bought it primarily so I'd have a little starter bike to teach my little 5'2" mom to ride, and have something small that I could rebuild without too much trouble. It's been an awesome learning experience and not overwhelming or annoying to work on.

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Offline Stev-o

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Re: 1980 CB125S seized piston
« Reply #63 on: May 14, 2020, 08:37:13 AM »
rags schmags...real sohcer's go for the distance!  I believe Steve-O is the current record holder at 28ft.?

It's only 17' Sean!   +1 on the Acetone/ATF cocktail, works wonders.  Heard it kills virus' too!!
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #64 on: May 18, 2020, 04:33:32 PM »
Pielz,How's this project coming along ?  :)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #65 on: May 18, 2020, 04:36:48 PM »
In an hour or two I'll be off work and going over to reassemble the engine!! Any tips on sealing gaskets or dos and donts?  Like should I use sealer on the head gasket? Or any gasket here for that matter?

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #66 on: May 18, 2020, 04:45:48 PM »
In an hour or two I'll be off work and going over to reassemble the engine!! Any tips on sealing gaskets or dos and donts?  Like should I use sealer on the head gasket? Or any gasket here for that matter?

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I like cleaning the gasket surfaces very well, then installing the gaskets without sealer.
Do you have any case bond sealer,the(one manufacturer:Yamabond 4 comes to mind..) non-hardening type? That's what it needs for the top half of the cylinder head/cam case mating surfaces;just a very thin 'skin' of it possibly using a safety razor as a tool to spread it on sparingly to one surface:don't let it sit for too long before assembly.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #67 on: May 18, 2020, 04:59:53 PM »
I don't actually have any hondabond or anything similar. Will anything else work like some sort of rtv? Or do I have to wait to get some of that? All I have is indian head shellac gasket sealer

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #68 on: May 18, 2020, 05:31:19 PM »
The RTV silicone should never be used on a place where there are oil passages,it'll clog into those passages and seize your engine,imo.The Indian Head will harden too much and 'shellac/glue' your cam case cover on.The non-hardening crankcase sealer is recommended,that's what I always use.Do you have any members(or a powersports repair shop?) live not far from you who may already have an open tube of it? When it first opens,it should be used-up within about 6 months otherwise it will dry and be unusable.. Needs to stay in a cool spot to store it with all the air removed from the tube.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #69 on: May 18, 2020, 05:33:31 PM »
I've seen on hondatech forums that some folks use permatex ultra grey? I know it needs to be non-hardening. No unfortunately nobody close by to me.

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #70 on: May 18, 2020, 05:41:50 PM »
I've seen on hondatech forums that some folks use permatex ultra grey? I know it needs to be non-hardening. No unfortunately nobody close by to me.

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Permatex ultra grey ? That may work but I am not familiar with it
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #71 on: May 18, 2020, 05:57:58 PM »
So I guess ultra grey is the closest equivalent to hondabond that I can get at AutoZone. Fortunately the dude at the counter told me he's sealed valve covers on old Honda's using this stuff and never had an issue. So I'll go with that! I'll keep ya updated. It should be back together this evening.
 
Stay tuned, I'm sure I'll have some dumb questions lol

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Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #72 on: May 18, 2020, 06:19:19 PM »
Dumb question number one, where do these go? Nothing like this came out of the engine and I got a pair of them with both gasket kits I have. These came with the piston/cylinder kit

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Online grcamna2

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Re: 1980 CB125S seized piston
« Reply #73 on: May 18, 2020, 08:42:04 PM »
Those are very cheap valve stem seals;you would only use them if you were going to disassemble the valves in the cylinder head.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Pielz

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Re: 1980 CB125S seized piston
« Reply #74 on: May 18, 2020, 08:46:57 PM »
Oh awesome. Im not doing that so it's fine. I'm a little stumped here. The crank needs to be at top dead center and the cam chain sprocket needs to be lined up with the witness mark on top, yeah? I have the chain around the sprocket and all that seems lined up right but I can't seem to get the sprocket around it's spot on the valve cam. Did I assemble something in the wrong order?

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