1972 CB100 Honda..maybe for the wife.

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
I picked up a 1972 Honda CB100 cost me 50 bux.

Really in bad shape, engine locked, wheels rusted through.

Everything that can rust is........

Missing seat, headlight, sprockets.

I've never built an engine b4, as far as replacing piston, rings and stuff. Changed some head gaskets and such.

It's a single cylinder, so how hard could it be.

Proven harder than I thought. Hopefully be able to stay up on this build.

Recovering from prostate surgery and having to return to work tomorrow will kinda stretch this out.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Yeah

Was hoping you'd check in on this thread. Hopefully, pick your brain on this thing.

Pretty messed up.
 

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trek97

No Custom Title
DTT BOTM WINNER
If you suspect its the piston thats froze.

Try mixing up some homebrew penetrant. ATF/Acetone - 50/50 mix. Soak the old sparkplug for a while...(Dont want to break plug off trying to get it out 8) ) Then pour a couple teaspoons down the sparkplug hole. Put a heat lamp on it for a couple DAYS. I use a cheap quartz work lamp (gets nice and hot). Give her plenty of time to soak and warm up.

Then try to break her free...gently. Dont want to break kick starter or anything else in there. :eek:

In the event its the tranny or broken cam chain or something else thats got her locked up.

After thinking about it for a minute. I would get her good and juicy, pour a bit in every hole shes got. valve adj covers, pull carb and muffler a give her a squirt in there to coat valves and seats.

What could it hurt? you might be replacing "something" in there.
 

trek97

No Custom Title
DTT BOTM WINNER
NOW, in the event you are the luckiest man alive and she breaks free pretty easily. Dont crank her over 50 times just because your happy and you can. ;) Dont want to suck a bunch of nasty oil into the pump and system.

While shes still warm from the heat lamp. And because Acetone and ATF mix arent really formulated for maximum lubrication. add a teaspoon of fresh motor oil to spark plug hole and squirt the other areas. Drain nasty oil from crankcase and refill w fresh.

Then bolt her all back up and get her started and running good. :D

Also, you will use leftover acetone for cleaning and ATF to fill the forks. Its a win win.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Nah, the engine piston is locked tighter than crap. The first pic is of the spark plug hole, that the po said has been open forever, so for sure there's water been in there for some time.

Pulled the head and the piston is froze solid. Tried everything I could to get it off.

I know I took pictures of the piston, can't seem to find them.
 

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whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Also got the wheels apart, and they are shot as well.
 

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JB77

Been Around the Block
Depending on how much time, money, and energy you want to put into that bike, you might want to look for a functioning 100 or 125 motor to swap in like 45exmayor is. I'm going to follow along, glad to see you are being motivated by other small singles
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Well, I'm rebuilding the engine, top side at least. Got the piston and cylinder off, and the inside of the trans and crank looks good.

I've never dug this deep into and engine b4, but beings its a single cylinder, shouldn't be too too hard. I'm hoping.

So got a new piston, rings .050mm over the original size. Had the cylinder bored to that size.

Got used/new to me wheels and shocks....think they came from a cb125, cause the speedo cable connector is different.

Got another head too, cause the original looked to be beat the heck out of.

I just can't find the pictures I thought I had.
 

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trek97

No Custom Title
DTT BOTM WINNER
Ha, looks like your farther along than I thought.

Did you download the free manual?

http://www.dotheton.com/downloads/Honda%20CB100%20CB125%20CL100%20SL100%20CD125%20SL125%20Workshop.pdf
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Looks like you're in for. A good bit of fun on this one. Im starting to like all these small singles happening on here. I'll be checking in
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
trek97 said:
Ha, looks like your farther along than I thought.

Did you download the free manual?

http://www.dotheton.com/downloads/Honda%20CB100%20CB125%20CL100%20SL100%20CD125%20SL125%20Workshop.pdf

yep, got it.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
adventurco said:
Looks like you're in for. A good bit of fun on this one. Im starting to like all these small singles happening on here. I'll be checking in

Cool, I like these little things to, just hope I can get it going after sitting under a tree for the last 15 years or so.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Well, here's the result of a vinegar treatment on the tank I bought:

Started as pin holes, opened up when I grinded to clean them up.
 

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trek97

No Custom Title
DTT BOTM WINNER
thats exactly what I had. The local radiator shop soldered it right up in one day. Along w other spots he felt were questionable.

He promised it wouldnt be pretty. he was right. But its solid and holds gas. :D For $60 bucks.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
trek97 said:
thats exactly what I had. The local radiator shop soldered it right up in one day. Along w other spots he felt were questionable.

He promised it wouldnt be pretty. he was right. But its solid and holds gas. :D For $60 bucks.

Not so sure theres a local radiator shop around will touch this thing. Even after several days with that vinegar, the surface inside still looks toasted.

Not sure I will be able to use this tank.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
deviant said:
Looking good, Bud. Shame about that tank.

Thanks Eric..........I'll have to figure something else out.

Right now, I'm more concerned about getting it running.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Frame and swingarm and lower triple tree stripped, sanded, primed and painted.
 

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whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Also installed All Balls head bearings. Only thing is the bottom bearing just slipped right on, didn't have to do any banging or pressing.

Feels tight though.
 

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