Ignition causing engine siezure ?

[andyp62]

Hi all,
my 1977 GS 750 has stood for a while and when I tried to start it I had no luck, I noticed the points were barely opening so I opened the gap to the correct setting and the engine started fairly easily, the problem was as it ran longer it started making a pinging noise and on revving it, there appeared to be slowing down of the revs until it stopped. The engine was locked up, after much spraying wd40 down the bores and jumping on the kick start it freed off and turns over but I am reluctant to try and start it. My question is could opening the points affect the engine in this way or is it possibly just coincidence and something else is wrong with the engine?.
Any help much appreciated , I am not sure what I can do to check the engine over and don't wish to damage it anymore.
Thanks in anticipation.

[Nessism]

The points won't cause the engine to seize like you describe. Is there oil in the engine?

[Steve]

Opening up the points will change the spark timing by advancing it.

I don't know if it would advance it enough to cause the bike to overheat to the point of seizure.

.

[Nessism]

Did you run the engine for an extended period of time while stationary? Air cooled engines need air moving over them or they will overheat.

[Brendan W]

If the oil level checks out you could have over advanced the timing.
This will result in the mixture being lit too soon, pre-ignition ( pinking) and overheating.
Did you check the timing after opening the points?

[Nessism]

No way the points caused the engine to seize, I don't care what happened to the timing.

[Brendan W]

Wanna bet?

[Nessism]

Wanna bet?

Yes.

I've seen holed pistons from detonation. Spark plugs with the gap bridged. Combustion chambers pitted all over. But all these things took a fair bit of time to develop along with a calloused user ignoring massive warning signs. The situation as mentioned here does not suggest such abuse. GS engines aren't fragile two stroke engines.

[andyp62]

i havent checked the timing after , need to go do that and re start it
cheers

[andyp62]

it was running for maybe 10 minutes, not any undue length of time really
Cheers

[andyp62]

there is oil showing in the sight window, is there any weak point on the lubrication system ?

[andyp62]

Thanks for all the input guys I will get the oil drained and check out the pump