Yet another project with an engine

nadams · August 2006

So, my dad still has his first motorcycle.... a 1967 Yamaha YDS3 Catalina. It hasn't been on the road since '82, and I was not able to get it to kick over. So, I decided to go ahead and put it into "restoration in progress" mode. The motor is out and the heads are off after a day's work, now I just have to get to tearing into the bottom end. I would like to be able to get away with honing the cylinders and just replacing the rings with stock sized ones, but I might have to bore the cylinders out and put in a set of .50 over rings.

Here are the pics, before I go to work

Stripped down bike with most the major bits removed.

30,683 miles, on a 2 stroke engine that, until today, had never been apart.

The seat is dusty, but still in fairly good condition.

The gas tank needs a paint job, though the decals are all in good condition. The inside is a mess of flakey rust, that's going to have to be removed and sealed before use...

The 247cc engine.

Twin Mikuni carbs

Two side covers removed, exposing the fluid clutch (left) and the Autolube mixer pump (right). The Autolube system, for those that don't know, automatically mixes straight gas, and straight oil, into the appropriate ratio depending on engine revs and how far the throttle is buried.

Looks worse than it really is. What looks like rust here is just carbon that's been saturated with cleaner. The flash gave it the reddish tinge. Still, some cleaning to do. The cylinders don't look like they're in bad condition, but getting the pistons out without scratching the cylinders could be tricky.

capecodder · August 2006

Gonna have to be a labor of love. Not sure you'll get your $ out of this project, but you probably already realize that.

Hell, I like the vacuum in the shot with the gas tank. Where did THAT come from. Make sure you don't grab that instead of the tank when you put it back together. Or then again maybe it would be a cool mod.

dkg999 · August 2006

You might not want to put the stolen "road closed" sign in the next set of pictures :eek:

ND13 · August 2006

dkg999 wrote:

You might not want to put the stolen "road closed" sign in the next set of pictures :eek:

KINKS wrote:

Silly boy ya self-destroyer.
Paranoia, the destroyer

:cool:

nadams · August 2006

PENNDOT can have the road closed sign if they want it... I honestly don't know where it came from. I think we found it in a creek on our old property after a flood...

As for the engine, it may not be as bad as we think. I just ordered these just in case... couldn't pass it up for the price - http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170018914688&sspagename=ADME%3AB%3AEOIBSAA%3AUS%3A11

I'm actually going to go out and tear into the bottom end now to see how things look... wish me luck!

audiobliss · August 2006

Gl!

...

nadams · August 2006

Got the pistons out and the jugs off. The one piston was stuck fast to the jug because it was just barely exposing the exhaust port. Even moisture getting though from the exhaust is a ****. Used most of my can of PB blaster, and a lot of tapping, and it finally unstuck. We need to get a cylinder hone now and prep the cylinders for the new pistons.

We did crack the one piston (the stuck one) when we were tapping, but it didn't scratch the cylinder walls on the way out. We went slow and kept it well-lubricated from top and bottom. This engine should almost be like new with honed cylinders, new pistons, and new rings... My dad still has a gasket set from the last time he worked on it, and it still has two head gaskets and two jug gaskets, and they all seem to be in good condition, so we should be set to put it back together.

I hate to say it right at the moment, but it looks like this might not be such an involved project. Of course, there's still the rest of the bike to work on (swingarm bushings, electrical system, front shocks leaking, front brake cable broke, cleaning out the gas tank, etc)

nadams · August 2006

Today I spent most of the day cleaning the frame and components. On to the pics!

Before the cleaning commenced.

After cleaning (removed the rear swingarm for easier access)

This chain guard was about 1/8" thick with black greasy crud. I was actually surprised to find that it was chrome.

The clean swingarm, with wheel and shocks still attached (quickest way to remove it).

I didn't know the rear wheel was chrome, either! (pardon the water spots)

This is where it starts to worry me. On the side of the conrod, in the "maha" part of "Yamaha", there appears to be some cracks that aren't present in the other conrod. Stress fractures or casting defects? I was hoping to just get away with a bore job on the cylinders and oversized pistons, and have this engine running relatively easily.

The engine, overall... I built a table just to work on the engine, as it collapsed my card table.

Gauges, all cleaned up...

All of the wiring for the headlight switches, horn switch, key switch, and gauge lighting is contained in the headlight shell... It looks like a mess, but I have schematics that are very clear!

By the way, all the cleaning and crud removal was done with Simple Green Max, diluted 1:1 in water. Worked great!

disneyjoe7 · August 2006

Yes, the cracks on the connecting rod does make me uneasy also. If there that little puppy was rev'd over it's limits. I wonder if it those could be welded then reground back to shape and weight? That's if no replacement could be found.