Can someone please explain engine break in period?

[tkent02]

If you ran the bike 50 miles without ever letting it get warmed up the gasket might be OK.
The valve stem seals have been hard as a rock on every thirty year old engine I have taken apart. Whether or not they smoke. Some do, some don't.
And,
If it runs well enough for your purposes, leave it alone.

I'm sorry too. Ok, compression check I can do. I don't mind taking it apart to get the cylinders honed. I'm an old hack at taking this thing apart. What I am concerned about is reusing the head gasket. An OEM gasket (which is the only kind that I have read on here that I should use) is $75. I can't imagine mine being used for 50 miles cannot be reused. Hell, I'm taking it off and putting it right back on. That makes sense to me, but obviously, what do I know. As for the valve stem seals, can someone please give me a part number? I doubt anyone has them in stock. I'm still dubious about them being bad as before the rebuild, that didn't happen and I didn't touch the valves.

[chef1366]

I'm truely sorry you didn't do your homework on this.
If you're happy with how it runs than run it.
The smoke is probably from the valve stem oil seals. If it was the rings it would smoke under heavy load. Hit the throttle hard to redline in neutral. If it doesn't cough smoke than your oil rings are ok. You may or may not have gotten a great seal on your compression rings. Checking your compression will tell this tale.

[tkent02]

Seriously they are designed to seal once, and they usually do.

I have heard of people using them again, have not heard of a re used one staying leak free for years.

For the amount of effort involved, and again to do it right if/when it fails, I would not bother.

I love backhanded answers.

[tkent02]

T
Can I really not use the head gasket again?

.

Sure you can, it might not leak for a while.

This is bogus. So are you suggesting I buy this kit for just the valve stem seals? Or for the head gasket? Can I really not use the head gasket again?

When I look in the fiche, what is the part number for the valve seals? There are guides and that is it. About 11 bucks each.

By the way, my engine is from an '81.

[tkent02]

What he says is that the sharp peaks in the cross hatches wear away that quickly.
They are the part that actually does the cutting.
Once they are smoothed over not much else happens.
The part you can see lasts thousands of miles, sometimes hundreds of thousands.
This is good, it helps hold oil on the cylinder walls.
But the ring cutting ability is gone right away.

There is a lot of BS about breaking in engines, always has been, always will be.
Most folks have no clue what is actually going on inside.
What Motoman says has always worked for me, guys who build engines generally agree.

Even Ray.

[Nessism]

Not honing and not replacing those valve stem seals is bad. The rings are not ruined though, they just won’t seal properly.

A partsnmore.com GS850 gasket kit is $65 + $5 shipping. Comes with the valve stem seals and everything else you could want. Call it a cheap lesson. I’d pull the engine back down and get the cylinder honed this time.

Getting back to the mototune break-in procedure, what I’d like to know is how can the cross-hatch get destroyed without correspondingly wearing the rings? And if this“critical break-in period” stuff is true, how come there is not more talk about it in the motor vehicle industry? Sounds like internet fueled urban legend.

No, never took the valves out.

[chef1366]

Did you change the valve stem oil seals?

[tkent02]

Maybe it will work OK then.
Let us know how it turns out.

Good luck.

Kinda like burnt oil and other things. Before I tore it down, it did not smoke oil at all. I doubt it is the head, but you never know.

I've been working on this bike for 2 years almost. Slowly bringing up to be a RELIABLE rider. I figured this was the last hurrah to make that happen. I've got nice, rebuilt carbs, jet kit, 4-1 exhaust, pods, everything that (in my mind) is new and reliable. I have now done this rebuild and hell, it starts up first crank when cold. Very nice. I like to do casual riding. Longer trips. I also use it to commute. From time to time, I really like to hit it hard and see how fast she can go. I like to ride her hard most of the time. Really open her up.

I'm going to ride her hard for a while, see if that clears anything up. Maybe things will settle. Either way, I think it is running pretty well. We'll see.

[Dave8338]

I forgot to mention, it smokes at startup when cold. Goes away after a minute or so. Arg... Honing sounds like the way to go.

What color is the smoke and does it smell like burnt oil?

I wouldn't tear it down quite yet. Put a few miles on it...a few thousand miles on it! If you have to break it down then, at least you'll have had the majority of the season to give it a best shot.

Myself...I'd run it and see what happens. Wouldn't be the first time that things clear up with a few hard miles and you're not going to hurt the rest of the engine by doing so.

[tkent02]

That smoking at startup is most likely a head thing, old hardened valve stems, maybe worn guides to go along with it.

What are your plans for this bike anyway?