Posts
18
Joined
10/27/2019
Location
Lewiston, ME
US
Edited Date/Time
2/16/2020 6:50am
Why oh why do I buy cheap old (but not that old) bikes and get them running? To support the second hand parts market? See if my wife’s ability to swear is more fluent (she’s Hungarian)? Or maybe because garage therapy is pennies on the dollar compared to traditional psychotherapy. Well, I don’t know.
But here is my latest lost cause, a nothing special 1987 RM125 H with seized engine.
As you can probably guess I got it off Craigslist for $200.
Complete (well, we’ll see) but with mangled handle bars. And you can’t forget the free mouse nest in the airbox!
I’ll cut to the chase, the engine was seized because of this.
Left side crank bearing.
Why did it seize? My guess is.....
A catastrophic failure, probably ring failure. Look at that head! That thing had some s#%t in it!
Anyway after cleaning the brown goop out of the jug, no it’s not rust, it’s really really comprised engine oil, it looks to be pretty good.
So the engine comes out of the bike so I can clean up the frame, and scrape all the melanoma off the plastics.
So, as for a complete bike, everything initially looked complete internally..... but. I realized that something didn’t look right on one of the gear shift forks. The stopper cam and spring were missing.... of course. At least the little pin was still there.
Now it’s a waiting game, I’ve got both parts on order.
All total, I have just under $400 into this bike. I’ve salvaged some parts, rummaged though my parts boxes (my wife always tell me it’s junk, I should give it away!) and found many useful things, was able to get several key components like bearings, and stopper cam new, for reasonable price. Maybe it’s not a lost cause? But will it run?!
But here is my latest lost cause, a nothing special 1987 RM125 H with seized engine.
As you can probably guess I got it off Craigslist for $200.
Complete (well, we’ll see) but with mangled handle bars. And you can’t forget the free mouse nest in the airbox!
I’ll cut to the chase, the engine was seized because of this.
Left side crank bearing.
Why did it seize? My guess is.....
A catastrophic failure, probably ring failure. Look at that head! That thing had some s#%t in it!
Anyway after cleaning the brown goop out of the jug, no it’s not rust, it’s really really comprised engine oil, it looks to be pretty good.
So the engine comes out of the bike so I can clean up the frame, and scrape all the melanoma off the plastics.
So, as for a complete bike, everything initially looked complete internally..... but. I realized that something didn’t look right on one of the gear shift forks. The stopper cam and spring were missing.... of course. At least the little pin was still there.
Now it’s a waiting game, I’ve got both parts on order.
All total, I have just under $400 into this bike. I’ve salvaged some parts, rummaged though my parts boxes (my wife always tell me it’s junk, I should give it away!) and found many useful things, was able to get several key components like bearings, and stopper cam new, for reasonable price. Maybe it’s not a lost cause? But will it run?!
Poll
Nothing keeps me centered better than tooling around in my garage at 2am on a Friday night, listening to PulpMX and rescuing some poor, forlorn, abused and disused Honda pulled from the moldy bowels of some barn in southern Ohio. Hell yeah it’s cheap therapy. And thank God my wife tolerates it, good luck with the Zook.
My latest:
The Shop
I intend to paint the whole engine with Duplicolor Ford blue and attempt to prevent any other magnesium from pitting.
The water pump impeller, like piston and ring appear to be new, never run.
The engine, other than head, and stator cover is in really good shape, even the stator despite looking rough is working fine. Thank you. On related topic, did the bike come stock with DG pipe? Or is it after market? The bike I have has a very nice DG with no dents or dings and very light surface rust since it’s not painted. I really have to wonder if it was new.
I think the PO attempted to rebuild but gave up when he couldn’t get the crank bearing off and then just buttoned it back up. I don’t know. It’s a fascinating little engine.
How do I install the stopper cam and spring?
Thanks for the assistance, I never figured this little bit would stump me.
Pit Row
Sure would be easier to do left side first... but I’m an idiot I got everything together and functioning correctly doing it totally backwards. Well until I realized the jug is out of round. 😩
So it’s off to the shop to get bored.
So the end is in sight,
It runs but smokes.... a lot. Also throws crank oil out the exhaust, so, yeah that’s epic. So obviously I have to fix my mistake.
My question is, while I have it apart, to replace right side seal for good measure, should I replace the left side again too?
https://youtu.be/L9Aazi4JhC8
That’s exactly what I’m doing now, while I doubt I’ll ever love these late 80’s RM 125’s they are fun to wrench on and pretty inexpensive on top of it all - though I hate spending money on a bike I’m just going to to play around on, being able to do that for less than the cost of a new crank for an ‘07 RM125 is nothing to complain about.
Thank you.
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