Klr250 crank case pressure and oil dripping from Exhaust por

[snowwolf]

Hi All, I have a 1987 klr250 which I have not long purchased, I’m a bit gutted as I think the engine is faulty.

the engine feels like it has good compression when kicking over, it starts easily too but when running I am getting engine oil leak from the seal where the exhaust manifold bolts to the head, the oil is clean oil and not burnt, if I rev the engine there is no smoke from back of exhaust.

if I remove the engine case oil filler plug with engine running there is quite a lot of air pumping out, can anyone suggest what could be the problem, I’m thinking piston rings failed as sump pressure but how is the clean engine oil getting into the exhaust port ?

[xeny]

snowwolf said:

how is the clean engine oil getting into the exhaust port ?

Exhaust valve guide/oil seal failed ?

[snowwolf]

That did go through my mind too, I will take Exhaust off and start it up, should be able to see if that is the case

[powerstroke]

sounds more like an oil leak from the valve /cam covers or oil feed and don't worry about the air movement a single cylinder will always pump in and out ..

[xeny]

powerstroke said:

sounds more like an oil leak from the valve /cam covers or oil feed and don't worry about the air movement a single cylinder will always pump in and out ..

Must admit I’m wondering how oil can run down the exhaust valve and not get cooked.

[graham22]

powerstroke said:

sounds more like an oil leak from the valve /cam covers or oil feed and don't worry about the air movement a single cylinder will always pump in and out ..

Thinking the same, or possibly head gasket failing around an oil way. Has it been rebuild recently and something like an o-ring on the head ripped or missed out.

With the oil being clean and no smoke, it's unlikely to be a combustion type issue.

[Mr2Mike]

powerstroke said:

sounds more like an oil leak from the valve /cam covers or oil feed and don't worry about the air movement a single cylinder will always pump in and out ..

If it's clean oil then it hasn't been through the cylinder or exhaust port. And yes, you have to expect a lot of crankcase pressure variation on a single cylinder engine.

[snowwolf]

Thanks for the replies, the guy I purchased it from said he had fit another engine, it does look like it has been worked on before, it also has a manual cam chain adjuster fitted, I’m finding it really odd that the clean oil is seeping out from Exhaust gasket area, I will take Exhaust off tomorrow see what I can see

[Mr2Mike]

My main worry here is whether a previous owner has sheared an exhaust stud off, and then done a very poor job of drilling it out and managed to break into an oil gallery etc.

[snowwolf]

That did go through my mind too, I will take Exhaust off and start it up, should be able to see if that is the case

[snowwolf]

[snowwolf]

As you can see in photos, the Exhaust stud has been drilled out and helicoiled, first photo is the cleaned up, second is when engine has been ticking over for a few mins, looks like it has been drilled close to an oil way and oil now leaking out around thread of helicoil, any suggestions on what I can use to seal ?

[graham22]

Bonus points to Mr2Mike.

That's going to be an interesting repair.

[snowwolf]

I did a search on the net and surprisingly a lot of engines cars and bikes suffer from the problem, I am going to RTV the stud into the head see if it cures the problem which I did earlier, takes 12 hours to cure so will let you know tomorrow if it works

[orangefzr]

snowwolf said:

I did a search on the net and surprisingly a lot of engines cars and bikes suffer from the problem, I am going to RTV the stud into the head see if it cures the problem which I did earlier, takes 12 hours to cure so will let you know tomorrow if it works

Have a look at timesert inserts they're way better than that helecoil ste ..... I wonder if they do a blind insert ? That would solve the oil leak

[snowwolf]

When out for a ride today and no oil leak at stud