Glutton for punishment 71 Yamaha cs3

Akastus

Been Around the Block
Well, I finally did it, I fell off the deep end. There was a guy out here that had a 71 Yamaha cs3 200cc 2stroke for dirt cheap. It was ugly and didn't run. He claimed the usual "ran when parked" which I NEVER believe. At the end of his ad he said he was interested in some trades, and it just so happened that he was looking for a pair of saddlebags. Well, I just so happened to have some laying around. Some talking with him, and an exchange of bags and a few bucks later I'm now the new owner.

Plans are to cafe it out (because that's what the kids want out here) and sell it!

Pics forthcoming

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Cool bikes, I just got a CS5 running (with 55 og miles!) and sold it off. Be careful with those carbs -- I needed one for the CS5, used one I found from a CS3 (after a lot of searching) but the choke mechanisms were different...
 
Alright guys heres some pics from the craigslist ad:

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Those bars had to definitely go! I ended up giving them to a buddy of mine that owns his own shop. Turns out, he just happened to be looking for a set for his brother in law.

So I get it home and check it out a little closer. The engine is free and a quick compression test shows that it has alright compression (not perfect, but still decent). I throw a battery in that I had sitting around, and after a spark plug cleaning and recharge, I had spark!

So off come the carbs, and I gotta tell ya, they were horrendous! It looked like an alien landscape in those bowls! But, I cleaned them up rather diligently, and slapped them back on. Previous owner had some sort of plumbing tap attached to the tank, so I just bypassed it with a funnel and new hose. My plan was to see if it would fire up. Well, I kicked and kicked, and even though it coughed a couple times nothing happened...

Eventually, I tinkered enough with it to get the thing to fire up, but only on one cylinder. A quick inspection of the cold cylinder revealed that the sparkplug was grolly (must have not cleaned it as well as I thought). A quick cleaning, and it fired on the first kick, yay! Not only did it fire right up, but it idled too!

SCORE!

So, as is tradition, I grabbed some parts from work and ordered a crap ton of other stuff. Heres a list!

-Michelin Gazelles
-Fork seals
-grips
-mirrors
-headlight ears (I just happened to have an EMGO 6.25" chrome headlight assembly lying around. Freebie!)
-Clubman bars that i had lying around as well (because thats what all these college kids want) though I may switch to drag bars
- clutch, throttle, and brake cables
-airfilters
-chrome generator cover
-petcock
-Fiberglass cafe tail from hotwing glass
-RK chain
-tailllight
-gear shift lever

Plans are to cut the rear fender down a little, mount the cafe tail, paint up the body work, slap on all the new stuff, clean up the chrome, and sell it.

Also, heres where it sits now:
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Color test while I wait for my parts

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Its a color called cast coat iron. Looks like anthracite with a slight gold tint to it. I think ill go for it
 
Parts have started steadily coming in. So far I have the petcock, cables, generator cover, and fork seals. I already have the tires, battery, and grips. I have replaced one fork seal (these forks are wierd), cleaned up a bunch of chrome, mounted the tires, and painted the tank and one side cover. This next week is going to be a mad dash to get all the stuff on.

Also, this 2 stroke gunk is hard to remove! Upside is that it has preserved the chrome very nicely on some parts :)
 
Seat came in!

Does anyone know the size of the oil injection lines, and whether or not I can replace them with rubber hose? They are really brittle, and one snapped on me
 
mine is in storage but if you cant find the line size pm me and i can go measure it on the weekend
 
I got it all taken care of. We have 1/8in polyurethane tubing at work, ends up it fits really well! So, you may want to file that one away

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Ok, weird stuff abound! I bought an LED tail light. I tested it by touching the leads to the battery, and the light is good. The battery shows 12.5v. When I hook it up the the harness I get no light. So I test the harness. I'm getting negative 12.5v. And when I hook up the light backwards it turns on. So, what gives? The headlight comes on and it's showing negative 12.5v at the plug. Problem is that I can't get the brake light to turn off unless I engage the brakes... Any ideas what the Heck is going on?

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Well, that took forever! I finally figured it out. It took a lot of trial and error, a plumbus, and some fancy wire work, but I got it functioning properly. Phew! Now to throw some gas in it, and some injector oil... Tomorrow

Right now, i need to pay attention to the Puch, the CL175, and my buddies KZ750
 
Picture time!

New tires :)
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This is what I am shooting for:
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almost done a few days ago. I didn't like those headlight ears, so I swapped them out
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Night shot 2 nights ago
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And done! except the wiring which I finished tonight
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So I took it out for a spin. Fun stuff this little bike is. Unfortunately, I now know why it sat for so long without being ridden. The tank leaks. There's a tiny little crack on the underside of the tank. Not, what I was looking forward to

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After tackling the tank problem...TWICE, I took it out for another spin. Immediately lost the left cylinder, though it would pop from time to time. Cleaned the carbs, only to find they were fine. Replaced the plugs, only to have it still happen.

I tested the compression 90psi, and 70psi... Crap! looks like some rings are in order. I was soooooooo close too!
 
I use to ride race bikes for a couple of shops. When I rode TZ250s for the local Yamaha dealer, we used a CS3 as our practice bike. It was pretty quick for the time and with a little port work and a good set of chambers it will haul. Glad to see one saved.
 
Great build! Love the tank color. Thats a shame about the cylinders. Loose coils maybe? Had the same problem on my 750 and turned out to be a loose electrical connection to one of the coils. This made it test fine sitting still, but would crap out on the road.
 
Hey guys, sorry ive been away for so long. School and work has been kicking my butt!

New rings fixed the compression issue. So, thats good.

I posted some pictures of it on my facebook, and a friend of mine immediately fell in love with it. Looks like shes going to buy it off of me. Ill be taking it out to her at the end of the month.

Heres how it ended up:

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So there you have it. Yamaha CS3.

Heres the before and after just for comparison
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So, any reason why it would be smoking out of only the right exhaust? I checked the injector line and it's flowing, I checked the port and it's open. The cylinder is running, so it isn't that either

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