Oil in left intake with new valve stem seals?

[pekka]

Hi guys!

I'm running out of ideas. I honed cylinders last winter and also had bushings put in to the exhaust valve guides and had a valve done job. After rebuild the left cylinder smoked bad and there was fair amount oil in the left intake. So I tore it down again and put in new valve stem seals. No help. Smokes like hell and lots of oil in the left intake.

The seal is seated. Breather is open. Intake valve lash set at 0.15mm. Intake valve "side play" is in tolerance. Head gasket does not seem to leak (at least not outside).

Any ideas what is going on? Did I just f*ck up the stem seal installation or can the guide be somehow faulty? If the oil would be coming around piston rings then it should not end up in the intake. Right?

Any recommendations for quality stem seals?

Pekka

 

[Paulrxs650]

Did you use new rings when you hones those bores? Also what type of hone did you use? Bottle or stone type?

 

[pekka]

Old rings because the ring gaps were well in spec. Yes. Mistake. I know. Tried to save money. Used a stone type hone (that three legged thingy).

You think that the oil could fly up to the intake from the cylinder?

Pekka

 

[Paulrxs650]

When you hone the bores you must use new rings. My money is on that. Stem seals tend to smoke on start up, normally white, then clear. Pop the head, lightly hone again (careful, those hones remove material quickly) check piston / bore clearance and if alls in order, new rings in

 

[pekka]

Yep. Thats propably what I have to do. Too bad. Lots of time wasted. But still I can't uderstand how the oil would end up in the intake duct.

You know the old saying: If at first you don't succeed, fail.

Pekka

 

[Paulrxs650]

Possibly as it s splashing around it getting in there. To check, pull the carbs and clean off that area. Pop that valve adjustment cover off and dose the spring etc with oil. Leave overnight and observe the results

 

[pekka]

Now that I think of it... I have a check valve in the breather tube. Last night one thing I tried was to run with out the check valve and somehow I think the smoking was worse (rather difficult to make any objective observations after banging your head to the wall for a few hours). Maybe the small vacuum created by the check valve kept some of the oil from leaking past the ring.

Pekka

 

[Paulrxs650]

Perhaps - it may create a little more pressure in the case??
What are your plans?

 

[pekka]

What are your plans?

First I think I'll cry a little. And when I eventually feel better I'll do a compression check (and leakdown test of some sort). When that confirms what you said in the first reply then it is a teardown and an order to Heiden Tuning...

Pekka

 

[Paulrxs650]

Don't cry
A compression check may not show up the issue as it could well be that the oil is giving a "false" good compression reading.
There is also Yambits in the UK - http://yambits.co.uk/
worth a look