1968 Yamaha YCS1C

spazzed

New Member
Hey guys -- I started over in the member introduction section but thought I'd locate it closer to where it should be. This is my first vintage motorcycle project so be patient as I describe things.

I picked this little 2-stroke up off of craigslist for what I thought was a very fair price. Bike was in better condition than I thought in many ways but worse condition than I thought in several other ways. Here's a photo of right when I rolled it into the garage:

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You can see that the only thing obviously missing on this side is the oil pump cover. I don't have a clean shot like this from the other side, but on that side it's missing the side cover and the generator cover is held on by coat hanger wire (ughh!) To my surprise, everything is actually in better shape than I expected once I started taking it apart. I thought that things were rusted or corroded, but actually they are just covered in 40+ years of oil and dirt.

My main goal right now is to get it started but first I needed to get it cleaned up -- that meant starting to take things apart and assessing what mechanical components I might need.

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Carb was rebuilt by the previous owner (before he lost interest in the project.) Engine has good compression and kicks over strong. Before it starts I need to resolve these issues or find these parts (hence the spending my time cleaning until I get parts or work out these issues):

- Boot that connects carb intakes to airbox. I ordered a NOS part but it seems to be the wrong size on the carb ends (or else my carbs have been changed at some point.) Air tube has 30mm tubes, carb has 34mm intakes.
- Also need air filter elements. Coming up empty on this one. Might need to ditch the airbox an adapt a K&N cone filter to the snorkel boot somehow.
- Wiring. All of the switches and lights on this bike should be in the headlight/speedo. Mine is missing the original headlight and speedo. There are random wires inside the current headlight bucket but I need to figure out what they are for and how they should be hooked up. (more to come below on this)
- Cables -- I now have all NOS throttle and clutch cables that just need to be hooked up.
- Spark plugs. Minor, but I'm waiting for mine to come in with a handful of other misc parts as well as a new battery.

Generator visually looks to be in good shape. No broken wires or terminals. (You can really see the caked on oil/dirt in the background of this shot.)

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This caked on mud/oil is what I'm working on resolving right now. It is covering EVERYTHING on the bike. Here's what the front wheel cleaned up like with just a little soap and water and my brass brush. I think with some elbow grease and chrome polish, she'll look brand new.

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Rear wheel and hub are also cleaning up nicely. I'll pull the chain and soak that in kerosene to see if I can get it bright again. Those shock springs are going to be a challenge. The "bonanza" version of this bike (which is my best guess as to what this is) seems pretty rare. The high pipes, front shock boots and rear shock springs seem to be the big differences. No idea where I'm going to find these but hoping once I measure, I'll be able to source some aftermarket "generic" ones.

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Tank will eventually need some work and paint on it. But... it's all there and dent free. Has both side covers and both pads (which are also dent free.)

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Inside looks great, though!

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Headlight. Can anyone identify this? The bucket is not bent or dented -- that's a flat spot on the bottom!

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Key on the top which is attached to something... but.... who knows if the bike has ever run like this?

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And lastly the pipes. Showing just how dirty they are and how nice they look after just a few hours with some steel wool, brass brush and purple power degreaser. I'm trying to figure out how I'm going to flatten the dented "muff guards." They aren't too bad but there's a few places where they have noticeable deformities in them.

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I'm actually really conflicted. It's a somewhat rare bike that is mostly complete. I don't have the money to do a full-on restoration but it seems like it would be a shame to molest it too much.

That being said -- I can picture it with a solo seat, hidden battery, pod filters and a MUCH smaller oil tank tucked up above the rear fender.

Job #1 is getting it running. Job #2 is riding it all summer. Job #3 is deciding what's next. ;)
 
Trying to sort out carbs. Only the RH one has a number on it. Since I didn't do the carbs, I really have no idea about them. I suppose it might make sense for me to soak them overnight in some berrymans and see if I can get the rest of the paint and corrosion off before I try to run them.

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Here you can see that it is stamped 793 (or 193??) E1.

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Does that mean anything or help identify if they are the correct ones? Fingers crossed that they are going to work. I looked through my service manual and parts diagrams and can't find anything that describes which carbs should be used or what the intake sizes should be.

My engine case is stamped CS1. As is the head tube.

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Some googling on how to measure/identify mikuni carbs found http://www.chopcult.com/forum/showthread.php?t=2837.

The carbs you want are called the VM series, and you would like to use the VM-30, VM-32, and VM-34. There will be no model number stamped on these carbs. You can make sure you have one of those carbs by measuring. You take four measurements. The total height of the carb, the total width, the width of the intake and width of the "outlet" or side to the engine. All measurements are done from the outside lip to lip.

This page: http://www.mikunipower.com/VM01.htm lists the VM32-193 (cha-ching!) as the right side version of the VM32.

Still no idea if it's the factory carb for this application -- seems rather large for such a small engine -- but maybe it will work?

Up next.... tail light. This has certainly been replaced but I'm wondering if anyone can identify. I sort of like it and I'd like to find a lens.

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Ignore the mud on the rear fender (which has been cut....) I haven't made it that far back in my cleaning, yet.

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Lastly today -- tank covers. Mine are painted. Most of the images online are of polished ones.... because of this, I assumed that these side covers were aluminum. Mine are certainly steel. I've yet to see one of these bikes that didn't have polished/chrome side covers. To get that look do I have to have them chromed?

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Subscribed! Love to see these little 2strokes come together! My recommendation for the tank covers would be to polish the crap out of them. Cheaper than chrome!
 
tomgbda said:
My recommendation for the tank covers would be to polish the crap out of them. Cheaper than chrome!

Will they polish up pretty nicely being just stamped steel? And then what do I spray over them to stop them from rusting?
 
The little 180 is a real fun bike and you did pretty good with your purchase.
To the best of my knowledge, none of the 180's, 200's, YDS's etc ever came with alloy or aluminum tank side panels - they were either chromed or painted steel and bolted onto the tank. By the look of it, yours were chrome once upon a time and now, they aren't...so either paint, powdercoat or re-chrome.
A lot of the Honda, Bridgestone, Suzuki, et al tanks of the same era had bolted on panels; I was told one time but was never able to confirm it, there was a requirement to have crash protection for the tanks - ie, a double wall which is what the side panels are really, but it must have died out sometime around 1969. I do have a couple of '60's tanks around the shop without the double sides and honestly, they weigh a ton so maybe their steel is a lot thicker.
OTT, there are a couple of Achille's heels with these bikes - the center crank seal is prone to failure (these are vertically-split crankcases), the big-ass starter on the end of the crank tends to bend things if you like to get real aggressive on the throttle and the almost-solidly mounted carbs - like all the Yamahas from the same era - are harder to set up and for some reason wear out sooner (vibration?). There are solutions to all of these problems, the easiest being to remember that you're riding a 40+ year-old bike and treat it as such.
I love the high pipes - I had a big brother 200cc CS3C and foolishly sold the high pipes from it. If you look closely on your mufflers at the stinger end, you'll probably see something stamped into them that references a fellow by the name of Jack Krizman, who was a wizard off-road / desert rider back in the '60's, built a lot of incredible stuff. He patented and licensed a lot of stuff to Yamaha, way back when, including the design of a lot of the mufflers used.
You've bought a great bike.
Have fun with it.
Regards,
Pat Cowan,
Vintage Motorcycle Fiberglass
 
Pat -- Thanks so much for the info and kind words. I love learning more about these bikes as there isn't all that much information online about about this era of bikes. It is interesting about the tank protectors as almost all of the mid-late 60s jap bikes have these. Must have been some kind of reason.....

pacomotorstuff said:
By the look of it, yours were chrome once upon a time and now, they aren't...so either paint, powdercoat or re-chrome.

Actually, now that I think about it -- I don't think they were ever chrome. The backside of these has quite a bit of surface rust and no sign of any chrome. They must have decided to paint them that day for some reason.... I was really looking forward to a black bike with chrome accessorys but not sure it will be in the budget. I'll have to work up an alternate color scheme that can highlight those tank protectors as they'll be much easier (less$$) to powdercoat or paint.
 
Ok I'm over here now! Great work so far, and if you need ANY help on carbs, feel free to bug me, as they are kind of my specialty. I'm sure I can swing by sometime soon. Stoked to see you keep going on this one.
 
Yeah - I'm going to need carb help. I'm worried that these might be too big. They're a little dirty and since I want to avoid any kind of problems, I think I'm going to take them apart and soak them. But.... I need to figure out what size needles and jets to order. How do I figure this out?
 
Check your tank side covers closely. I had a 180 with the scrambler pipes in the 70s and the tank panels were chrome and all of them I've seen were also chrome. It's possible someone painted over yours...at an extreme they might have stripped the chrome. Nice project, they are great bikes in town.
 
Rider52 said:
Check your tank side covers closely. I had a 180 with the scrambler pipes in the 70s and the tank panels were chrome and all of them I've seen were also chrome. It's possible someone painted over yours...at an extreme they might have stripped the chrome. Nice project, they are great bikes in town.

No way these were ever chrome unless they somehow only chromed one side. The inside is unfinished/rusty. These covers appear to have factory paint......
 
What you say about the inside of the tank panels sounds about right. It seems that Yamaha took care of the outside of the panels as regards prepping, polishing and making sure there was a good -for them - plating strike and said to hell with the inside surfaces.
I used to take the panels off my YR1 tank once or twice a year and give them a good waxing (totally anal 17-year-old), which worked pretty good and some of the guys painted the insides to slow down the rust.
Regards,
Pat
 
If you are keeping it stock, there's no need to get new jets (if those are the right carbs that is) If you are changing fueling and air, then you should change jets. It's fairly simple to just clean em out. Let me know what some good days are for you and I'll swing over with all of my carb cleaning tools. It would be cool to see this thing, and its been a while since we've met up.
 
Word! I'll let you know when I at least have most of the parts that I'll need to get it going.... Waiting every day on UPS and just not getting the last few bits.

The question about the jetting is because these carbs don't appear stock. A guy on 2strokeworld is working on the same bike and he has smaller carbs. His are stamped code 174 and mine are stamped 193. http://www.2strokeworld.com/forum/index.php?topic=14428.0

His measurements match up perfectly to the Mikuni VM18 specs. Mine don't match up to anything. http://www.motorcyclecarbs.com/About_Mikuni_VM_Carburetors_W143.cfm

A real head scratcher.....
 
I think that tank panels were a cheaper way to mimic British bikes with chromed sides. On a BSA they had to polish the sides and plate the whole tank and then paint over the top and bottom leaving the sides shiny. It's easier and cheaper to have a simple panel that bolts on.

Your plan is spot on. Clean it, run it and think about the next step. It isn't perfect but those are fairly rare now.
 
What PacoMotorStuff said is correct. The insides of the tank panels were not polished and only "flash" plated which leads to rusting. Remove some of the pain on the outside of the panel and I'll bet you will be surprised.
Rider
 
There is NO WAY that a 180cc bike is running VM32s unless it has a massive amount of internal engine work and it is a race bike.

Looking at the original parts fische, the stock carbs seem to be Mikuni VM26sc. The problem youll find though, is the goofy stock mounting system. Youll need adapters made to mount universal 26mm Mikunis.
 
Your carbs should be 18 or maybe 20mm carbs at the largest - check it with a mike or even a ruler.
Those old cylinders used spigot mounts and you'd be able to tell pretty quickly if someone had modded them (look for yards of welding and oodles of grinding marks).
I doubt whether a 180 would even run on 34mm carbs... the TA125 production road racer came with 28's and it was a bit dodgy at times.
Remember, you have a piston port motor with 90cc cylinders. I think a hot rod mod from 1969 was to bore out the spigot, do a little bit of welding and use another Yamaha carb - maybe from the 125 single sloper motor - 22mm I believe it was for a performance upgrade. If I remember correctly, AHMRA among others have a 22mm carb limit for these little motors, probably reflecting what was run back in the day.
If you're really stuck for carbs, email me and I'll see if I have any small carbs around.
Regards,
Pat
 
Carbs are 18's guys not 26's or 34s. Isn't there a thread on just the carbs
 
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