first 2 stroke rebuild

[Tekime]

I don't know much but that looks like chipping to me, not cutting. Then again I try not to use stone tools

Flushed it out a few times? Any evidence come out in the drain?

On my DR (which granted I knew to have metal bits in it) there were fragments hiding in the tiniest places, no way I could have found them without splitting the case. But you would think with the damage to that piston there would be some evidence elsewhere...

Good luck!

[number9]

i'll trade you a kdx I have for your el camino

I wouldn't trade it -- too many bikes already -- but if you're interested in buying it, let me know. I won't be asking that much for it as it's a basketcase right now...

[TheIglu]

El camino....Go on......

[black]

some more pics of the cylinder....KDX new pics - Album on Imgur
here are some more update pics of the cylinder and one of the piston
[album]http://imgur.com/a/nUo5H[/album]
basically the inside felt very smooth, more so after a light rub with a scotch brite pad
there is some "smearing" but its on the bottom of the cylinder not the top and towards the intake side.

i did find a small "hairball" about 3mm x3 mm in a corner very odd, was not magnetic

[number9]

El camino....Go on......

'69 painted (badly) in metallic midnight purple. Was built with a Powerglide but previous owner converted it to a TH350, which I freshened up. Was built with a wheezy 350 but I rebuilt it with a 383 (well, 385) stroker kit. Ditched the heads for Chevy Vortecs, Edelbrock intake, new valve springs and guides, rebuilt Quadrajet, new headers etc.

Interior is stripped as I'm in the process (the stalled process) of putting new floorpans in it with new, proper sheetmetal. You're welcome to come and take a look...

Have rebuilt gauges for the interior, rebuilt steering column, new trim, new just about bloody everything.

[Paul_E_D]

Hmmm, that motor is pretty sacked out. Doesn't mean it won't do another 100 hours on a fresh piston though. If I cared about performance, I would send the cylinder to millenium for a recoat. But if I were in your shoes, I's slap a good piston in and move on the the suspension. FWIW I restored a 91 in basically the same way. It was great afterward

[black]

my first time looking and "diagnosing a cylinder" what are the tell tale signs of it sacked out? the streaking? shoudl it look pretty pristine and crosshatching very visible??

[Paul_E_D]

Well, like all things motor, other than obvious damage you have to measure it to determine how good/bad it is. The diameter needs to be the same top middle and bottom.

[black]

Well, like all things motor, other than obvious damage you have to measure it to determine how good/bad it is. The diameter needs to be the same top middle and bottom.

diameter at top ( or 20 mm from top) is within spec. Manual doesn't state to measure the bottom or middle.... Is that necessary?

See my eye looking at this sees nothing major going on ( but I'm a newb and your guy's eyes are better than mine)

[Paul_E_D]

diameter at top ( or 20 mm from top) is within spec. Manual doesn't state to measure the bottom or middle.... Is that necessary?

See my eye looking at this sees nothing major going on ( but I'm a newb and your guy's eyes are better than mine)

THat is how it is done. yes.

[carsick]

diameter at top ( or 20 mm from top) is within spec. Manual doesn't state to measure the bottom or middle.... Is that necessary?

Are you talking about the piston or bore? Are you measuring with a dial bore gauge, or an inside micrometer, or telescoping gauges? Bores should have very little taper, and need to be measured top, middle, and bottom both in the thrust and non thrust axis. Pistons, on the other hand, are made tapered and are a lot easier to measure with a caliper to get close 'nuf. Not only is there taper on the piston top to bottom, some are slightly oval at the middle when cold to allow for even expansion taking into account the pin hole and reinforcing bosses.
Except for the KDX, which was probably cast in a discarded soup can.