1977 CR 125M "barn find"

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Sep 22, 2025
Messages
110
Over the years when I have visited my cousin and always took time to peek at this bike being weathered inside the backyard shed. A few weeks ago we decided to pull it out and try to start it. It's been in the shed for about 25 years. Before that his ex wife had it and rode it. Last registration was in 2001 when their son was a baby.

With some not too old fuel that had oil in it I got it to start after a few kicks. It immediately stalled and fuel poured out everywhere from the carb. Knowing it had good compression and would run my cousin decided he wanted to put some money into it and get it running.

At this point he has a decision to make. A full concours restoration is not in my DNA. I have seen plenty of them and it's just not me. Not to mention I would not have the patience to tackle it. Thankfully he had the same idea as me. Just get it ridable so his son can take it out and have some fun.

OEM parts are near impossible to find so I very carefully started to tear it down and make a list of parts. Here is the mind blower. Upon close inspection I have determined this bike has less than 15 hours on it!!!

The hardest part was finding carb rubber and the float valve assembly. Float valve is the old design with the rubber in the female port. Jets are standard and I kept them stock size. Only thing I did was raise the needle one clip to maintain the integrity of engine.
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The air filter disintegrated at first touch. it was never touched since the factory. This was to be expected. Being a simple piston port design means no reed valves. Everything else is easy peasy.

Went on Rocky Mountain, Amazon and Ebay. I got pretty much everything except air filter. UNI Filter manufacturing is near me so I went there and they had the air filter in stock.

Naturally I will be using Sunoco 100 at the pump and Maxima 927 for this bike.

We have spent less than 500 bucks. I am not going down the full restore/upgrade suspension rabbit hole.

Here are some pictures of the bike and date code on the tires. Date code matches up with bike being the 40th week of 1976. The absolute mind blower is the fact Factory Honda used 2 rim locks on the rear tire. I have never in my life seen this. I always have to drill and add an additional rim lock.

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The brakes are virtually brand new from the factory!! Sprockets have zero wear and chain is a stiff rust belt!!
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Over the years when I have visited my cousin and always took time to peek at this bike being weathered inside the backyard shed. A few weeks ago we decided to pull it out and try to start it. It's been in the shed for about 25 years. Before that his ex wife had it and rode it. Last registration was in 2001 when their son was a baby.

With some not too old fuel that had oil in it I got it to start after a few kicks. It immediately stalled and fuel poured out everywhere from the carb. Knowing it had good compression and would run my cousin decided he wanted to put some money into it and get it running.

At this point he has a decision to make. A full concours restoration is not in my DNA. I have seen plenty of them and it's just not me. Not to mention I would not have the patience to tackle it. Thankfully he had the same idea as me. Just get it ridable so his son can take it out and have some fun.

OEM parts are near impossible to find so I very carefully started to tear it down and make a list of parts. Here is the mind blower. Upon close inspection I have determined this bike has less than 15 hours on it!!!

The hardest part was finding carb rubber and the float valve assembly. Float valve is the old design with the rubber in the female port. Jets are standard and I kept them stock size. Only thing I did was raise the needle one clip to maintain the integrity of engine.
View attachment 339112View attachment 339113

The air filter disintegrated at first touch. it was never touched since the factory. This was to be expected. Being a simple piston port design means no reed valves. Everything else is easy peasy.

Went on Rocky Mountain, Amazon and Ebay. I got pretty much everything except air filter. UNI Filter manufacturing is near me so I went there and they had the air filter in stock.

Naturally I will be using Sunoco 100 at the pump and Maxima 927 for this bike.

We have spent less than 500 bucks. I am not going down the full restore/upgrade suspension rabbit hole.

Here are some pictures of the bike and date code on the tires. The absolute mind blower is the fact Factory Honda used 2 rim locks on the rear tire. I have never in my life seen this. I always have to drill and add an additional rim lock.

View attachment 339114View attachment 339115View attachment 339119View attachment 339119

The brakes are virtually brand new from the factory!! Sprockets have zero wear and chain is a stiff rust belt!!
View attachment 339116View attachment 339118View attachment 339120View attachment 339121
Dennis Kirk to the rescue don't forget - https://www.wiseco.com/product_model/cr125m/mke-honda/yer-1977/mdl-cr125m/
 
What a cool blast from the past. Like many of my generation I grew up with bikes before this and really appreciated the Japanese move towards better suspension and power. This generation of 125cc was a nice transitional step from 4 inches of suspension travel to 12 inches or more.
 
I love it!

I had a 1977 RM125 - and the engineering is comparable (the RM had a bit more travel, I think, from looking at it) but that was such an exciting time in motocross - every year brought huge improvements in suspension, power, and handling.

Looking at this - it is a time capsule. Those brakes are amazingly clean, and a great clue to the history of the bike.

It takes me back.

Nothing like a two-stroke 125 MX bike - keep it “on the pipe” and the combination of light weight, good handling, and good power make it really fun to ride.
 
1st legit dirt bike I owned was a '78 RM125. Twin-shock rear suspension and 40mm carb. Just remembered how much you had to "stay on the pipe"/fanning the clutch when climbing a hill, else it was bog city. There are a few abandoned railroad right-of-ways that went through town I'd use to blast-down the graded rail bed. Just get this RM125 into top gear and it would rip - Gemini says its top speed was 60 mph - I believe it! Remember the occasional raised access point for getting over the tracks - served as a few great opportunities for catching air.;)

No gear except a motocross helmet. Ah, the teenage days of invincibility!
 
Thanks everyone. this is a very fun project!! I'll keep you posted on how it runs after I'm finished. Also surprised at how well the grease looks in places like the rear brake pivot.

Don't forget the crank seals!

If I ever tear down the motor I'll change out all the seals. As it is I will fuel it and ride it for now. According to my cousin it gets started every year or so.

If it ain't broke don't fix it. As long as there is no hanging throttle it will be good to go. I remember the factory seals on Hondas being robust. I have not dealt with a 49 year old 2T but plenty of 20-30 year old ones big me brother in laws CR500.
 
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