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sucking tranny oil

3K views 2 replies 3 participants last post by  augiedoggie 
#1 ·
Hi guys , new to forum only my second ktm but had bikes my whole life and a good mechanic. I bought a 2003 ktm 65sx for my son and he loves it. when i got it the crank bearings were going and it was mixing oil/water. I split cases and replaced crank/bearings/seals/gaskets. back together and engine was sucking crank oil and obviously burning it(smoking like crazy and smelled like burning oil. pulled right crank seal and replaced with oem, no more smoke but still seemed to be losing oil through exhaust. thought maybe waterpump was still leaking as well so replaced waterpump shaft and oem pump seal. back together and still losing oil. split cases again to make sure gasket had not fell out of place on back side of crank(towards tranny gears) and all looked good. back together again and still losing oil through exhaust but not smoking. I have now replaced crank seal 2x, case gasket, head and base gasket 2x and water pump shaft with 2x shaft seal.
What the heck am i missing, my only thought at this point is the case or cylinder has a crack somewhere(although i did not see anything out of ordinary.

forgot to add, the first crank seal pulled did have a tear from something(maybe assembly?) is there any chance the crank seal is bad again?
 
#2 ·
Cheers and welcome to the forum.

Just to get you more notice, I've moved your first post.
 
#3 ·
i recently had similar problem on my 250 and found the seal carrier sleeve uses small o ring between crank bearing and seal sleeve. my bike had previous repair or overhaul and did not tighten crankshaft gear fully and trans fluid got sucked under sleeve. you may want to check carefully in your parts breakdown and see if your motor requires a sleeve or o ring and if you may have a problem like i did if you did not install this o ring as it is easy to miss. its not a bad idea to suspect crank seal problems if you run ethanol additive fuels in any 2 stroke as the ethanol destroys the seal elastomers unless they are ethanol compatible. you can usually examine seals for elasticity, if they are hard or brittle you may find ethanol fuel is the culprit.
 
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