Man am I confused!

[JimmyR]

So I'm doing all I can to spruce up my "82 GS1100G and currently have some decent stock-ish pipes, some brand new RS36 carbs and lots of new seals, boots etc on my engine. As far as I can tell the engine has done around 98 000kms - maybe around 60 000 miles?

But lately it's been blowing a bit of white smoke, especially on start up with choke. When warmed up and running I can barely notice it, but when I pull the plugs they are a little oily and quite black.

So today I did a compression test. I did exactly as the tester manual and the GS manual said - kept the throttle wide open and cranked the engine until the needle reached it's peak. I had all of the plug caps off and even disconnected the ignition so that there was no spark anywhere. I pulled the plug of the cylinder I was testing but left the other plugs there to protect the cylinders - should I have pulled them all anyway?

So my confusion is in my readings. from 1-4 I got 180psi, 182psi, 182psi and 188psi. I was expecting rather a lot lower than that.

Do flatslide carbies with pods somehow raise the readings? Could a PO have already fixed the valves and pistons? And why am I still seemingly burning oil? The oil level in the side window is down to half-way right now after only 3-400kms.

Any clues?

Thanks guys!

[JimmyR]

Just spoke to a local Suzuki guy and he says it's probably all fine and that I should check how well my plugs are seating. That may explain the oiliness of the plugs (they were slightly oily on the threads when I pulled them) and the reason I'm apparently burning oil. Badly seated plugs. I will check and see.

Maybe a PO has done some work to the top end?

[Agemax]

most likely cause will be vave guide seals. they wont affect compression but if worn will suck oil into the combustion chambers causing the plugs to oil up and give you your puff of smoke.
it will be worse on choke as all will be cold and running richer so it will emphasise the problem.
60k miles is probably about the time the seals are beginning to wear, depends on how the bike has been ridden.
compression figures sound good though!

[JimmyR]

That sounds plausible. I'm thinking I might service the valves anyway. Thanks - I think you may be right.

[Spiff]

compression figures seems OK... If you do another compression test, remove all plugs as that will make the starters job easier

[Big T]

Someone did a good write up on replacing the seals with the motor in place recently. Saves pulling apart the motor

[Nessism]

Your readings are high. Either someone rebuilt the engine with high compression pistons or your gauge is off.

Smoke on start up is a sign of valve stem seals. There was a recent thread where someone changed them on the bike but frankly, I'd rate that person highly skilled so get ready for a challenge if you try the same.

I don't understand the loose plug business causing oil burning? That doesn't pass the smell test.

[7981GS]

I agree with Ed.
Very nice compression numbers! Hi-compression pistons.
What else does it have? Cams changed? (After-market cams would probably bleed off more compression though) Carbs?

Eric

[rustybronco]

Excessive carbon in the cylinders? (quite black plugs) Could be the cause of the white smoke as well. What's your fuel mileage like?

[chef1366]

The plugs not seating idea is horsesh!t!
Post a pic of your plugs using macro

[JimmyR]

Well the valve seal thing certainly makes sense to me. I'm thinking of taking the whole head off and servicing it completely. Can't hurt! Then I can check the pistons too.

Thanks guys, at least now I have a plan.

[john82q]

Jimmy,

My thread about doing the seals.

http://www.thegsresources.com/_forum/showthread.php?t=188696

Ed,

Flattery will get you everywhere! Highy skilled, BS!


Cheers John

[earlfor]

And why am I still seemingly burning oil? The oil level in the side window is down to half-way right now after only 3-400kms.

Any clues?

Thanks guys!

Generally, an oil level of half way in the window signifies the full line.
If you're putting more oil in the engine than that, you're overfilling it.
If you're overfilling it, the excess has to go somewhere. usually that will be out the breather and some of it burned off until the oil reaches the required level. Have you been measuring the amount of oil you put in the bike when you do an oil change, or have you just been dumping oil in until you see the oil window filled up?

[Nessism]

Generally, an oil level of half way in the window signifies the full line.
If you're putting more oil in the engine than that, you're overfilling it.

Um, no Earl. Half way up the sight glass is within the acceptable range, but it's not FULL. The proper way to check the oil level is specified in the Suzuki service manual: run the engine for several seconds to distribute oil within the engine, shut down, wait about 1 minute, then read the level (bike on centerstand). Suzuki calls for filling the oil to the "F" mark, which indicates FULL.

[7981GS]

Generally, an oil level of half way in the window signifies the full line.
If you're putting more oil in the engine than that, you're overfilling it.

Eric