1978 gs1000 compression

[kahuna]

just got a chance to check the compression on the motor of a project that I am about to get into.1978 gs1000 ec.She appears to have 115 lbs on all four with #2 about 2 lbs shy.What is the engine spec for compression new and what is the lowest before powder coating the frame gets put on hold?
Also, will either 1100 heads 16 valve or 8 valve fit?I figure If I have to do
the rings I might want to pump her up.Thanks for sharing your wisdom.

[Anonymous]

Sounds ok.

That sounds ok for an initial reading. IF the bike wasn't warmed up you can't really trust those readings. I would assume when you get the bike back together and warm it up the readings will improve. If the bike was warm and reading less than 110 Lbs, or a big dif between each then it would be time to tear it down.

[Anonymous]

comp

My 79 1000 has 30K and reads 145 on all four cold with carbs open and valves adjusted, hot it reads about 2lbs. more

[Sandy]

Sounds about right, wish mine were the even across the cylinders. Checked mine recently (79 GS1000) and here's what I had. Bike runs fine and no oil comsumption. Motor has only about 20,000 miles from factory new on it.
Cold 120, 112, 115, 120
Hot 132, 122, 125, 130

[Guest]

I got you All beat:

90,60,60,90(hot)

[earlfor]

Damn! I'm shocked it even runs. :-)

Earl

I got you All beat:

90,60,60,90(hot)

[saaz]

All below 100psi...a legend!

Readings should be bike warm, carbs fully open. Also take note of how many revolutions it takes to get up to pressure. Factory spec is 128 to 184psi, service limit 100psi. I rebuilt mine when it got below 120psi as it was also using oil.