2 Stroke What RM is this?

Hey everyone, I haven't been around much. I've had some life changing situations going on, and got into other things. I want this motor for reselling purposes or some "art" piece. I wish it had a frame, but I can't ride anymore! I found this for sale and I believe it's a 90's RM125 motor. Seller knows nothing about it and I'm curious what size it is before I buy it for a little tinker toy. Looks to me like the cylinder says 123, but RMs never came in 123cc right? I believe they are 124.8cc, then 250s were 246cc. It's hard to read so get your magnifying glass out! Thanks a bunch!
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Update, is that even an RM motor? Where do the reeds go? It can't be a 4 stroke there's no spot for valves or a camshaft. I'm confused, any opinions are appreciated!
 
Nevermind, I believe I found it. It seems to be an 81 RM125X motor. First style of the water cooled RM's with a case reed induction, 82 and up was switched to a reed cage. A piece of history if you ask me, I'm going to buy it. I'll clean it up and repaint it, then probably make a coffee table or something with it. Obviously leaving it in a usable state though. What do you all think I should pay for it?
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$50 was exactly what I was thinking. It would be perfect to make something with it. Need something to spend my free time on. Figure a cool paint scheme, a stand, and glass, would make a decent coffee or inn table. I'm tempted to cut a quarter or half out of the cylinder and head to display the inner workings of it. That way someone can learn something while they drink coffee
 
I'm still confused, the cases by the sprocket between the two are a touch different. Then it looks like the heads are different, and the black one doesn't have a power valve like the blue one. It must be an 81 because of the case reeds, 82 and up changed to a reed cage. So is the RM125X a tuned down version without a power valve, then they have a RM125 equipped with a power valve for more power? Maybe the RM125X/RM125 are like the modern day RMX125/RM125.
 
$50 was exactly what I was thinking. It would be perfect to make something with it. Need something to spend my free time on. Figure a cool paint scheme, a stand, and glass, would make a decent coffee or inn table. I'm tempted to cut a quarter or half out of the cylinder and head to display the inner workings of it. That way someone can learn something while they drink coffee

By the way, nice to have you back here. Sorry to hear you can't ride now, hopefully you find somthing to fill your time that you seem to have more of now.
 
I'm still confused, the cases by the sprocket between the two are a touch different. Then it looks like the heads are different, and the black one doesn't have a power valve like the blue one. It must be an 81 because of the case reeds, 82 and up changed to a reed cage. So is the RM125X a tuned down version without a power valve, then they have a RM125 equipped with a power valve for more power? Maybe the RM125X/RM125 are like the modern day RMX125/RM125.

No....the x was the model year designation for 1981.....they had a PE 175,250 that was the enduro version of the RM
 
Any idea why it's different then? Did they have a 1981.5 possibly? The introduction of a power valve seems like something that could wait for next year's model for better sales.
 
Any idea why it's different then? Did they have a 1981.5 possibly? The introduction of a power valve seems like something that could wait for next year's model for better sales.[/QUOTE

I remember that model as it was suzuki's first liquid cooled RM, I don't think there was a half year models I did some research of your question and can't find when the power valve first was intriduced on the 125
 
Oops didn't mean to make 2 posts. I believe I found the real deal! It's not a power valve, it's a Variable Exhaust Resonance Chamber. Like Hondas ATAC setup. Power valve was introduced in 87 on the RM250 called AETC "Advanced Exhaust Timing Control" AETC is commonly seen on the flywheel/magneto covers I think. I'll find out the first year the Variable Exhaust Resonance Chamber was introduced
 
Here's how it works anyway:

ATAC System: The Honda Automatic Torque Amplification Chamber system works by effectively increasing or decreasing the volume of the exhaust system with a small butterfly valve located just before the exhaust connection. At low RPM a centrifugal crankshaft driven gear opens the valve into a small chamber and increases the volume of the exhaust by allowing the exhaust gases to flow through the chamber. At high RPM the ATAC valve is closed and the exhaust simply exits into the expansion chamber. A larger expansion chamber allows for more power at lower RPMs because of the extra time needed for the impulse to "bounce" back for the supercharger effect. It was used on their CR motocrossers, GP bikes and MTX, MVX, NS and NSR road bikes. Only difference in suzukis system is instead of a crank driven gear, you manually turned the butterfly switching from low rpm riding performance to high rpm riding performance. I think that's how it worked anyway
 
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