Replaced base gasket, now my bike seems to have aged

[robsGS850]

Hi there,

So, after getting a few jaw-dropping quotes from the big shops to replace the weeping base gasket on my 81 GS850, I took a chance on a private motorcyle mechanic. Nice guy, fast work, replaced every gasket, checked the valves, made some extra effort, it all seemed pretty smooth. But…

now there's a TON of blue smoke coming out of the pipes (didn't burn oil at all before...), the engine stumbles and hesitates on acceleration and also backfires more.... he said it would just take a while for the valves to reseat (or words to that effect).

I only got a chance to ride it for about a half hour before I garaged it...

Is he right or did I make a big mistake? What gives?

thanks in advance...

rob

[scotty]

When head work is done. Valves are seated properly at that point. I would suspect that since you have valve shims. he may have a few over tight.

Rings seat


Thats back firing.--or maybe timing chain is off 1 tooth?????


Smoking ???? did you replace the old rings. If not then you may have disturbed the old rings.


Maybe he just replaced the gasket and rebolted everything together. The new gaskets would definiyely require valve adjustments,

Just thinking out loud

[BadBillyB]

Is he right or did I make a big mistake? What gives?


rob

No he is not right....The motor should have run exactly the same as before.....without smoke....as before.....Mistake?...maybe. A lot of blue smoke at idle indicates issues with the valve seals. Did he change them??....Blue smoke under hard acceleration indicate problems with the rings.....Did he have them off ????.....Nothing needs seating in, it's just a gasket replacement....As far as the running problem, the 850's are very sensitive to having a completely sealed air box....Maybe he left something loose or off....BadBillyB

[chef1366]

Are all your plugs the same color? Try to diagnose which cylinder or cylinders the oil is coming from. Could be an oil ring wasn't put on right.
I had a bit of oil burning from my bike after a top end rebuild but it ceased after the new rings seated.
Or it could be a valve stem oil seal.
Do a compression check to see if your valves are seated.

[Nessism]

Blue smoke doesn't have anything to do with the valves seating, a loose valve seal maybe but not seating valves.

Most likely the guy damaged an oil control ring putting the barrel back on. Sounds like your discount mechanic was no bargin.

[robsGS850]

Thanks, everyone.

Yeah, that's what I was afraid of. Sounds like it's all bad news. Serves me right, i guess. Ah, coulda been worse -- if I'd been the one trying to fix it.

Now it's going to have to sit for a month or more til the rainy monsoon season here is over... will that make it worse?

[renobruce]

Does this guy back his work? I would diagnose it myself, then take it back to him to fix.

[mark]

Now it's going to have to sit for a month or more til the rainy monsoon season here is over... will that make it worse?

Shouldn't hurt anything. If it sits for a while you could squirt a little oil (tsp) in the cylinders before the next start up......gas stabilizer would be a good idea too if its much longer than a month.

[RacingJake]

Before you give up and tear it apart again check a few things

Do a compression check and see how healthy each cylinder is.

Is timing correct on #1 cylinder, also check the firing order, maybe a plug wire is crossed. Check the pickups, maybe they are crossed.

Check your fuel bowls, is the level correct. Maybe some trash in the needle valve causing an overflow or a no flow condition.

When the engine is cold start it up and then quickly touch each exhaust pipe to see if they are all hot. If you have a cold pipe then you can check that cylinder, plug, wiring, carb for the problem.

You can also remove the valve cover and get the motor on TDC and check the cams for correct timing as per the book.

Good Luck