is this ok?

[J.ellwanger]

looking at the textured side of the crankshaft?which goes from BDC to half way up one side, (crank would be towards the intake side) is that something that need to be taken care of,
 and while I'm on this, I had a bit of piston skirt break off, and fall off some where,
but the piece is no where to be found in the bottom end crank area,  and there's no damage on the crank, chunks of metal, scratches, except the odd textured spot.

[sandblaster]

Just for grins...
What bike is this?
On the broken skirt, if it's not in the bottom end then it blew the piece or pieces out the exhaust port.
Shake your pipe and muffler to make sure nothing is in there rattling around..
I'll let others answer the bit on your crank..
Don't want to steal all their glory 

[J.ellwanger]

this would be my
1989 KX125 that i got to ride for 1.5 months

 I had the idea of rinsing my exhaust, W/ carb cleaner and was gonna say that's what i did, but that seemed like an odd thing to do. but I might as well do it.

and come on, leaving me on the edge of my seat for others to post, you were already here!!! 
  alright lets hear it!! whats up with the cross marks.

 untill my posts has a *NEW* posted to it, im back to figure out WHAT THE HELL you are doing to those pistons on USMC500. and to find my missing skirt

[J.ellwanger]

also meant to ask about the connecting rod, play which way for movement is ok, and what is not ok

[sandblaster]

How old is the crank?
Did you measure with a feeler gauge the clearance between the crank rod and the crank half?
If so, what was that number?
If not, get that number.
Also, did you rotate your crank around so that you could see the oiling slot at the bottom of the rod?
If so was there and obstructions or was it clean?

[sandblaster]

Again referencing the manual for the 88 kx125
Big end of rod side play New .40-0.50 mm
Service Limit 0.70 mm or .028"

[J.ellwanger]

I have not done any measuring...
 Guess i should get on that. And as far as age I'm not sure
How Long its been in the bike,   and also i have  not checked the  bottom of the rod, i have been spinning the crank, and haven't found anything blocking or stuck, but i have inspected the whole  piece, just not the rod itself, (looking for missing skirt ) but since I've found the skirt in a thousand  pieces in my exhaust,  I'll start looking and measuring all the specs on the bottom end

[J.ellwanger]

so did i ask a dumb question thats not worth an answer?

[sandblaster]

I've been out of town.
What was the question?
Also, did you measure the crank?

[Motorrad]

Id be concerned the skirt is wadded up in one of the bearings, or smeared in the race.... (mains)   it probably isn't. but I always think of worse case.

don't wory about the texture.


measure runout

[don46]

I'm the anal guy, if you haven't found the pieces, they have to be someplace, and if your fortunate enough that it didn't crack your cases, you had better make sure the pieces are gone or you could crack them. you have it out and almost apart go the rest of the way, check it out and replace at least the seals, I'd go bearings as well since there was debris floating around.

[J.ellwanger]

I was actually waiting for an answer on  the crank texture,
Thought to myself why measure anything if there was something wrong with it.  since i know not to worry about the texture,  I'll measure tonight when i get home. But have found some of the   piston, small pieces in the expansion chamber,   and i had the side of the case off already, and everything is clean, bearings  look in good working order  the case is clean checked out the gears, and there is no sign of  major wear on my gears, my cases show no sign of cracks,  as well as there are no scratches in the engine itself, so i going to say piston skirt got blown out,

[5hunrooster]

I don't use a silencer with a spark arrester, but if you're using one with a spark arrester the pieces could be clogged up in there also. Just a thought...

[J.ellwanger]

I do have a spark arrester, I'll pull that apart to, need to anyways,  but I'll check there, as far measuring tonight, i didn't get home till late, so I'm just going to bed, try tomorrow, but work SUCKS after a  holiday... Go from 8-5 to 8-8:3
  the American dream,

[J.ellwanger]

So, I finally got off my lazy ass, and split the cases all the way...
  Im gonna rebuild the whole bottom end as well, but questions on the crank, can it be machined?
 I inspected the bearings and on the transmission side, there is a roughness to them when you spin them, free, but rough, and my crank bearings Spin with no roughness,  but regardless,  ill be replacing all of them,
 And am thinking about replacing all of everything on the bike, swing arm bearing, and stem, yada yada yada,
 Pulling it apart after the Broncos Game!