Piston rattle? is that the same thing as piston slap? 

I did not do any clearance evaluation. 

With the exception of new copper gaskets this was how I purchased the bike. It doesn't look original?

   

Piston rattle/piston slap yes. Don't worry, she'll be good. Thanks for the clear pic of the oil union, good too.

But it's just been bored by a very reputable shop with new oem piston and rings. How can I have slap? I don't want slap.

For the love of Pete, make the slap go away!!!!!! please tell me how to eradicate the slap. please?

Welcome to the world of air cooled two strokes.

Look on the bright side.  They always give you plenty to think about, as you rattle off down the road.

To eliminate the slap, buy a liquid cooled one.

The time to worry is when the rattle turns into a distinct clatter.  That point is reached when you stop thinking " does that sound ok" to "good lord, that thing is about to blow".

Nice resto job btw.

Not sure if i should carry this on & worry you but if you're not happy [ie worried] you'll have to pull the cylinder & check the skirt clearance.
I wonder if it didn't quite clean up with the first over piston you supplied but was very close so not worth worrying you over it. [that's just a guess].
I expanded the pic & turned it 1/4 turn & can see vertical lines around the inlet boost port but probably can't feel them, just light marks.
What does it look like looking at the exhaust port in the same way--same light.
Have you felt the left side crank bearing for vertical play by just grabbing the flywheel. Easy to check.
If you 'do' lift the cylinder & remove piston, then rings off, see what number feeler blade slides in with the lower skirt in the area of the exhaust port. Have piston inserted as it sits in the bore ie arrow to the front.
Then invert it & try the feeler blade just above exhaust port. No pressure but it's what i do & having no good gear to measure but it's a good indication if its beyond spec.
When we had rebores done at the machine shop down the road from work you could check with 1.5 thou blade & they'd be spot on.
Always the same guy did the boring back then which was good. Not even sure where i'd go nowdays for boring in town--how times change
One more thing i just thought of--You could add rubber bits into the fins on head & cylinder to deaden the noise.
Do you think the internals of the exhaust are coming unstuck & accentuating the rattle, separate from the cracked shield.
Ok that's enough worry for one day/night.

Thanks Tinkicker. But I didn't do any cosmetic stuff. it was practically everything else though.

Thanks RT. I will order a new base gasket and ride until it arrives and then take cylinder off and check the clearances.

Yes I think you are correct about the first over size boring not cleaning up sufficiently. I think I got a little over zealous trying to smooth the exhaust port with sand paper.

I will live with the noise until the end of the riding season or until I blow up the engine and try with 2nd O/S over the winter. I will also keep an eye out for another jug in better condition.

Sounds great. Don't worry to much and enjoy the ride. I put my CT1C together and had a great time time riding in HV with some guys from the sight in SoCal. I listened to every noise for a few minutes. Once I opened 'er up a little and started riding it like I wanted, the fear went away. After I rode some trails and tried to keep up with the others my confidence soared and I really enjoyed my bike. I knew what I did to get her running good, I checked it out, I tested it, checked it again, determined she was solid, had fun riding my bike that I worked so hard on .

Ride it until it doesn’t run any longer. Then the rattle will stop completely…

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Well....

I've driven another 100 miles and have just noticed during the last ride that the noise goes completely away when I'm at a stop light and the bike is in neutral and the clutch lever is pulled in. When I let the lever out, the noise returns.

Does that indicate anything obvious?

I have not tried to put it in neutral while the bike has been in motion but I plan to try next time I'm out.

sounds terrific, congrads on this!

lots of oil too, so go riding and enjoy it!