smoking klx300

man.went out on my 1999 klx300r for the day. not checking the oil before. after about 4 hrs riding engine started making screaching noise . so stopped and checked oil ,not alot there had to lean the bike to one side till i could see the oil . so topped it up and ran fine did about 3hrs more riding .kicked it up 2 days later after giving it a new oil filter and oil filled to just under the middle of the markings . blue smoke comes out until it is warm then clears . if i do this then leave to stand for about 1hr the smoke is back think i have done rings or oil seals anyone had this problem before your advise would be very welcome:cry:

If you tear down the motor you might not like what you're going to see. I would be tempted to ride it as is but always go riding with a partner that has a good tow strap. The bore and ring damage could be causing the smoke but other parts may have also been damaged. Start looking for a used engine. It would cost more in parts, than the bike is worth to do a complete rebuild.:confused:

its true i just spent about a grand doing JUST the top end, and thats re-using the cylinder. i would suggest taking the top end off and inspecting it before you ruin something. could be something as simple as a ring set and maybe valve guide seals. should cost you around 50 bux or so, maybe worth it?

You should have looked at the old filter closely too see what it caught.

If you didn't get oil to the top of the engine the valve stem seals would be the least of your worries. If the bike was using so much oil that it got low enough to stick it was way overdue for repairs.

A head gasket is around $38, a set of rings about $35. If you lost oil pressure your crank/rod could be the first to go at $500 list price for a new one. And if the cam bearings starved for oil you could need a new head and cams.

If it's running ok I don't see how you could hurt it more than it already is by riding it. Like the other guy said check out the oil filter. Take it apart and see if it trapped anything inside. Did you change the oil and look for metal specks?

think i have done rings or oil seals

i had a look at oil filter but didnt think to open it.looked ok oil looked fine aswell. can i take the top end off whilst engine is still in the bike .

you can take it off but its not much work to get the engine out...making it loads easier to work on. 2 brackets, one bolt, and the swing arm bolt. un plug the wires, and take off the carb and pipe. and shes out.:confused:

thanks for your help everyone shall be taking it to bits at the weekend

ok,couldnt wait till the weekend to strip my bike so did it today.engine is out cams look fine i think, only one is a little blue:confused: cillinder is like pitted like its got a arch shape on one side of the cillinder about centre, and 10mm wide to1mm at each end.can some one give me guidence as to what the process is now please i dont think i can get hold of a 330 bore kit in the uk . i know a place that rebores would they tell me what size rings to get or do i get them first not sure never done this. i have looked though most of the other posts to find stuff related [slandry] sorry if ive got your name wrong i know you have just done this can u help. :prof:

So you lucked out and your crank/rod and bearings are good??? And the cam bearing surfaces look ok???

how do i tell.thing is before i had taken the engine out. and kicked the bike up. smoke cleared after 10mins the engine sounded sweet but did lack some power.

And the cam bearing surfaces look ok???

That's the first thing I thought when he said the cam looked blue. I'd be looking REAL close at that!

It takes some pretty high temps to discolor metal. For one thing if the cam is blue you could have damaged the heat treating. Cam lobes are hardened so they can withstand the heavy loads from the valves/springs. It would have taken insane friction to generate that kind of heat to cause the discoloration. You know that screeching sound you mentioned? That's from insane friction. Maybe from the cam journals running dry. A good machinist can weld up and re machine the head if you're lucky. ????????????????????

So the cooling system was full during all this or was it as low on coolant as it was oil???????

To check the rod if you don't have dial indicators. Grab the rod and see if you can feel any play when you push down and pull up on it. If you can feel any slop your crank/rod is bad.

the cooling system was full.i have since learnt the cylinder connot be bored it has to be resleaved but you know that.erm i did push and pull on the rod and it did nt have any play .i have sent cylinder to get resleaved was wondering if i have to replace the piston . im having new rings but piston looks fine.thanks for your time

YES replace that piston please!

The OEM piston is not too expensive so it could be cheap insurance to replace it. You say the old one looks fine. If you checked it with a micrometer and it is within factory tolerances I can't think of any reason it couldn't be reused.

Mesure it like OldXl told. But I would put a new one in anyway.

thankyou to everyone who gave me the advise i needed.fixed cost me £260 in total. been told to do 500miles to run it in using semi synthetic oil.whilst i had the engine out i inspected bolts/bearings etc.now then i cannot get the rocker arm pivot shaft bolt out. its not a problem at the mo but would like to sort it anyway.i undid the nut and had to work on loosening the bolt moving it left to right until it turns all the way.but it wont come out.think the pivot shaft bolt is bent slightly in the middle anyone had this before?

I had that problem with a 94 KLX 250. The OD of the pivot bolt was the same as the swing arm pivot bolt. It was bent & I had to drive it out with a drift punch. Keep at it, you'll get it. Straighten it out, check the needle bearings.

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