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Need help with oil leak

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Ok so When I did my first oil change on my kx250f i had to get a helicoil installed in the big drain bolt and ever since then there has been a slow oil leak out of it. I've bought a new crush washer, and tightened it down more is there anything else I can do to stop the leak I'm tire of having a oil pan under my bike.

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Yes, you take that case half empty to a machinist, hell fill the hole with a Tig weld. Drill press a straight, clean hole in it, and put fresh threads there...

You gotta lose that "keep tightening it mentality, because thats why you have this problem in the first place. 

The bolts way harder that the female threada. THERE IS A TORQUE SPEC. GET A BAG OF NEW ALUMINUM CRUSH WASHERS AND USE A NEW ONE EVERY OIL CHANGE. something thats so easy not to yet overlooked all the time. Now you gotta take your whole motor apart.

Anything else might "hide" the problem. That machinist will FIX the problem. Just bring him an empty motor... 

Theres also just buying a used case half off ebay.

I did work for a guy on his crf. I tightened with torque spec and it leaked. I told him the washer was new but still leaked that showed me the female was effed. I told him the problem. Told him that I wouldn't tighten tighten tighten cause thats the wrong way to do it cause thats how he has this problem to begin with. Told him HE could add oil and tighten tighten tighten, but it wasn't going to get done by ME. He then goes and blows his tranny (split case crf) cause it leaked all its oil out. Sure he could've tightened the crap out of it, but this makes the problem worse and is likely why hes dealing with it to begin with...

Dismantling isnt hard, its just time consuming. Either take it all apart to do this or take it all apart to replace everything once you ruin the motor.

Theres a specific way to do things. In a world of .001" you should spend a dollar on a new crush washer every oil change


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A helicoil is never liquid/air tight. It is simply a threaded shaped spring wound into a hole.  In other words the oil leak is coming along the bolt threads on the ID of the coil, along the case threads on the OD of the coil, and gaps between the spring windings (threads) of the coil itself.  It is like expecting a wire mesh screen pressed between plates to hold water; not going to work for that.   The helicoil is a great fix for repairing fasteners and holding a bolt, however it just cannot physically seal anything.  This is a case of a good tool (helicoil) selected as the fix and applied to something it is not designed nor capable to do.

The actual seal is the washer at the head of the bolt - and ONLY that washer.  If you have an effd washer or an iffy case surface around the hole or a roughed up bolt head surface for that washer to seal against, you will never ever get a seal.  First check the base of the pan around the bolt hole. Ensure it is clean and flat that there are no scratches in the washer seal area. Check that the area is flat, particularly that the end of the helicoil is not raised causing. Finally you may try other seal washer material (soft copper, softer aluminum, a hard phenolic plastic). Do not put anything rubber! -the bolt will soon fall out and well you can guess the rest. Another possible may be to put some sealant tape on the threads of the bolt; only a few threads near the head of the bolt at the washer area. The idea being to have minimum but just enough material to mash between the bolt, case and the washer to work, it may get you by.  All of these jimmy-rigs are workarounds to the underlying problem.  Being you are where you are and have what you have ... You now just need to figure out how to get a good seal on that washer, because the oil seal is not the bolt or case or coil threads, no matter how much you tighten it.  The correct fix is to have the hole welded or soldered/brazed closed, redrilled, retapped, new washer, new bolt.  Even then, the seal will still be the washer and its mating surfaces.  Focus on that.

Is the leak definitely from the bolt? Is the pan cracked? Is the case seam leaking? Sometimes leaks are coming from elsewhere and migrate to the lowest point which can be misleading ...

Just a few ideas to ponder. Good luck with this.

Edited by FaceDeAce

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