How does this Happen to a Piston?

[GabrielGoes]

My friends 78' GS1000 which has been down for a while... finally we got deep into the head and this is what we found! how does this happen? running it too hard? i heard that too much starting fluid can do this.

[Octain]

Although I have never seen it first hand most would agree that's the result of extremely lean running conditions.

Did the bike have an airbox on it?
Are the pipe blue at the head?
How many miles are in the bike?

[SqDancerLynn1]

Running lean, or miss adjusted timing

[Nessism]

Not from starting fluid. It's detonation from running lean. A few possible reasons that come to mind include...leaking intake O-rings, clogged carb jets, running pods and/or a header with the stock jetting. Sadly, all these conditions are easily avoidable.

BTW, I have a couple of spare GS1000 pistons if your friend needs some.

[GabrielGoes]

Did the bike have an airbox on it?
Are the pipe blue at the head?
How many miles are in the bike?

Nope

Headers were sprayed black

25k miles


we were completely blown away how good the walls and the rest of the motor was, not a scratch or blemish to be found ANYWHERE! the motor is beauty im gonna take pics tm

[GabrielGoes]

.

BTW, I have a couple of spare GS1000 pistons if your friends some.

im gonna let him know asap

[Octain]

I bet someone at some point ran that bike very hard with very lean conditions. Sux cause the bike prolly ran like $hit, which would obviously indicate a serious issue without even so much as picking up a single tool.

[bobthebiker88]

most definitely due to running lean, and the condition being blatantly ignored. never a good thing.

[GabrielGoes]

I bet someone at some point ran that bike very hard with very lean conditions. Sux cause the bike prolly ran like $hit, which would obviously indicate a serious issue without even so much as picking up a single tool.

the bike was running on 2 about 45 miles out my friend told me had to go wot home going 45 mph i guess you were right about that

[Graham]

Hmm, same bike that is in this tread.

http://www.thegsresources.com/_forum/showthread.php?t=168686&page=3

I'm sure it's not valve adjustment. Piston got too hot.

[rapidray]

It can also be too much timing. Ask Bill!!! Where you at Bill?!!! Ray.

[Octain]

It can also be too much timing. Ask Bill!!! Where you at Bill?!!! Ray.

By too much you mean too advanced?
Why would anyone set the timing like this, to make up for hard starts?
Which could be a valve adjustment issue and/or a jetting issue.
Boy, this one just keeps getting better and better.

[Steve]

By too much you mean too advanced?
Why would anyone set the timing like this, to make up for hard starts?
Which could be a valve adjustment issue and/or a jetting issue.
Boy, this one just keeps getting better and better.

Yes, "too much" is "too advanced".

You would not advance the timing to "make up for hard starts".
If anything, advancing the timing makes it harder to start.

Hard starts could easily be a valve adjustment issue, but it could also be a lean carburetion issue.

Bottom line: just do ALL the basic stuff we keep harping about all the time.
Adjust the valves, clean the carbs, change the oil, you should be good to go for a long time.

.

[Octain]

Adjust the valves, clean the carbs, change the oil, you should be good to go for a long time.

.

I guess none of this matters in this particular situation now.

[chef1366]

Read and weep

http://www.thegsresources.com/_forum/showthread.php?t=148511&highlight=symphony