2001 kx250 knocking

[RippinRy]

Recently noticed a knocking sound coming from the engine. Louder on left side. Top and bottom end were rebuilt about 8 hours ago (same crank though) Checked out the flywheel and looks good. Pulled the jug off the other day just in case it was the crank bearing but it's also fine. Bike runs mint otherwise. I've got a couple videos, really hope someone can help me out! Maybe it isn't really anything to worry about? Any help would be really appreciated. Thanks!!

2001 kx250 knocking?: https://youtu.be/l2eweIpQ3aE

2001 kx250: https://youtu.be/nnquiIsvN80

[MRDART]

Not sure, looked at a bunch of videos and they basically rattles a lot, hard to tell,  but make sure your enginemounts are tight, that can lead to a lot of strange noices... Other than that, check your clutch and after that main crankbearings, you have already checked the Top end, no Marks on the pistontop, no cracks in the piston skirts? No marks in the cyl/ head, pistonplay in the cylinder?

[tobys 2 strokes]

I just rebuilt my 01 250 and it has a very simular noise that also quites way down when you pull the clutch, I havnt figured it out yet

[sandblaster]

I just finished watching the first part of vid 2.
When you are rocking the flywheel back and forth and you can hear that knocking sound is there a noticeable area where you are feeling no drag until you hear the knock?
If so.... I'd pull the top again and look hard at the connecting rod bearing and the wrist pin bearing.

[RippinRy]

Thanks guys, I'm at work so when I get home I'll check it out. The head is still off because I'm waiting for the base gasket to come in (should be in today actually) With the head off you can still hear the clunking when turning the flywheel back and forth but it isn't nearly as loud and sounds like it's coming from the other side (near clutch maybe?) The connecting rod bearing looks and feels fine and there isn't much wear on the piston or cylinder. I will double check the wrist pin bearing though and I'll see if I can take some measurements of the piston and cylinder to rule out piston slap.. I guess taking the clutch basket off wouldn't be a bad idea either?

[sandblaster]

If it sounds like it's coming from the clutch then yes, pull all the clutch parts off and inspect everything.
but before you pull the clutch parts out, with the cover off, put the bike in gear and turn the flywheel back and forth while holding the clutch basket still.
If it's a clutch issue it should become apparent where the issue is.
Since you have the top end off, have you measured with a feeler gauge the clearance between the connecting rod and the crank half?
If you grab the connecting rod and try to move it up and down while holding the crank still, is there any noticeable play?

[don46]

I think the KX's have a death rattle sound all the time, some more prevelent than others. wouldn't let it scare me, you said it runs fine, if there was an issue with the motor it would have probably cratered already.

[RippinRy]

Ya I dunno guys, checked almost everything out and haven't seen anything bad.. Definitely not the rod bearing. Maybe I'll just keep riding while keeping a close eye on it..

[RippinRy]

Thanks again for all the help guys..