Lots of cylinder pressure when warm now.

[Guest]

As most of you will recall, I was only seeing 90 psi or less when I was trying to get the project bike started.

I am now very pleased to advise that after getting it going and running it today to fully warmed up I am now showing 180 psi plus across the board.

The bike starts easier now each time. Later I will be using my new Morgan Carbtune to balance the carbs. Hopefully that will make starting even easier.

Things are coming along nicely now and I am on target for a spring completion.

Cheers all.
Spyug

[Octain]

As most of you will recall, I was only seeing 90 psi or less when I was trying to get the project bike started.

I am now very pleased to advise that after getting it going and running it today to fully warmed up I am now showing 180 psi plus across the board.

The bike starts easier now each time. Later I will be using my new Morgan Carbtune to balance the carbs. Hopefully that will make starting even easier.

Things are coming along nicely now and I am on target for a spring completion.

Cheers all.
Spyug

Great!! Nothing feels better than when a seemingly hopeless project comes together.
Im a bit concerned about my 78. It seems that it has roughly 140 plus on three banks but one is around 70. I would think that if it were normal ware that all banks would be around the same. THe bike hasnt been tagged since 01 and looks like its sat in the eliments for a very long time. But it wasnt seized.
The bike is completly tore down to nothing but frame as I intend to replace, clean and restore it back to original with a few little mods.
It would suck to do all the work cleaning and painting, reassemble only to find that it needs a topend.
But Im gonna do what needs to be done in hopes that the one bank will "re-seat" it self after I get it going.
Reading posts like yours gives me hope!

[bmac]

bike restore

I would suggest that if you haven't adjusted the valves, make it a part of your things to do project to coincide with your rebuilding phase. After that being done along with a carb rebuild you will be ready for your carb tune. Good luck, Bmac

[SqDancerLynn1]

when bikes sit for a long time the rings can get gumed up and loose compression. I would not rebuilt an engine for low compression without running it for at least 1/2 hour. It is mandatory to adjust the valves..

[spyug]

Well I'd say Lynn is correct and this is the same advice my pro wrench gave. Get it running and see how it measures after it runs warm for awhile. Rings will undoubtedly seat in again and pressure will build unless there are broken rings or something off with valves.

Octain, I was wondering how you got your readings. If the engine is out of the bike did you tune it on a stand or were the readings taken before you ripped her apart?

Where you able to test with a bit of oil in the cylinder to see if pressure comes up any? If only one cylinder is way off, I might be thinking valves as opposed to rings and with that in mind Bmac makes a good suggestion in checking valve adjustment. maybe you want to check that before getting too deep into it.

Whatever is going on with it I am sure you will be able to get to the bottom of it. when do you figure you'll get the engine back in and be able to do some more testing?

Keep us informed of how its going and let us know what you find.

Good luck with it.

cheers,
Spyug

[Octain]

Octain, I was wondering how you got your readings. If the engine is out of the bike did you tune it on a stand or were the readings taken before you ripped her apart?

Where you able to test with a bit of oil in the cylinder to see if pressure comes up any? If only one cylinder is way off, I might be thinking valves as opposed to rings and with that in mind Bmac makes a good suggestion in checking valve adjustment. maybe you want to check that before getting too deep into it.

Whatever is going on with it I am sure you will be able to get to the bottom of it. when do you figure you'll get the engine back in and be able to do some more testing?

Keep us informed of how its going and let us know what you find.

Good luck with it.

cheers,
Spyug

Thanks dude. At the rate Im going it'll prolly be a while before I get it all put back together. Its kinda cool and humid to do much painting, parts and frame and such. Plus Im in no real big hurry and wanna do it right. Im afraid if I dont do this bike as well as I can I'll regret it in the end.
The Skunks are my favorite GS's and I wanna take my time with this one.


I checked compression before I did much of anything, right after making sure it wasnt seized. Hooked a set of cables to it and grounded the starter relay to get it to turn over.
The bike was complete minus the grab rail.
You may be correct about the valves. I'll cross that bridge when I get there.
Right now Im working on busted bolt on the exhaust side. Next will be the intake side. Yeah, on on each side
Next will be the cleanup.

[Big T]

Great!! Nothing feels better than when a seemingly hopeless project comes together.
Im a bit concerned about my 78. It seems that it has roughly 140 plus on three banks but one is around 70. I would think that if it were normal ware that all banks would be around the same. THe bike hasnt been tagged since 01 and looks like its sat in the eliments for a very long time. But it wasnt seized.
The bike is completly tore down to nothing but frame as I intend to replace, clean and restore it back to original with a few little mods.
It would suck to do all the work cleaning and painting, reassemble only to find that it needs a topend.
But Im gonna do what needs to be done in hopes that the one bank will "re-seat" it self after I get it going.
Reading posts like yours gives me hope!

I'm just guessing, but is #1 the low one?

I bet it sat on the side stand for years and gas ran in there

Don't worry about it as it's real easy on the 78 GS 1000 to do the top end with the motor in the frame

[doctorgonzo]

Had a long, and somewhat pointed, argument on OSS that you can't use cold compression numbers to compare to spec. If they are REALLY low, or they are all over the board, ok, that tells you something, but you can't take 100,100,100,100 (or 90,90,90,90) cold and know you have low compression.

[Octain]

I'm just guessing, but is #1 the low one?

I bet it sat on the side stand for years and gas ran in there

Don't worry about it as it's real easy on the 78 GS 1000 to do the top end with the motor in the frame

Nope, its either 2 or 3, cant remember but I do know its an inside cylinder.