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**gspaul** · 07-09-2005, 06:47 PM

Yep! Look's like the ring's!

**flyingace** · 07-09-2005, 07:05 PM

I wish my compression was that good! My lowest cylinder is 110, but my service limit is 100. My bike still runs fine, but I know a top-end job is around the corner.

I'm going to ride mine until the symptoms get bad enough to stop me or I get bored enough to start the rebuild. Symptoms like using oil, poor starting and weak engine performance.

To other GSers - is it common to just replace the rings or more usual to overbore with new pistons/rings?

Thanks,
Ace.

**gspaul** · 07-09-2005, 07:15 PM

Really depend's on the amount of wear, the bore's have to be mesured.

**sailor20034** · 07-10-2005, 02:17 PM

Leak down test

Although the add-oil test is usually a pretty good indicator, I've found that a leak down test will give you a much better indication of the engine's condition.

To do this, you need an air compressor with a valve that will allow you to regulate the pressure waaaaay down, and a spark plug hole adapter. You bring each cylinder up to TDC on the compression stroke, screw in the plug hole adapter, and hook it up to the air hose. Be sure that the air pressure is very low; if it's too high, the air will just turn the engine over and you'll have to start again. Remove the oil filler cap and the air cleaner hoses (or air filters if you have individual "pods").

While the air is flowing, listen at the carbs, oil filler, and muffler. If you hear air from the carb, you have a leaking or badly adjusted intake valve. If the air can be heard at the oil filler, that indicates worn rings. Air coming out the exhaust indicates worn/misadusted exhaust valve.

I learned this lesson the hard way when overhauling a VW engine. I did the "add oil" check and found that the one weak cylinder increased, so I though it was rings. Once I dismanteld the whole engine, I found that it was a cracked cylinder head. I could have just put on a rebuilt head and gone on my merry way....as it was, I ended up spending lots more money on a full overhaul of the engine.

**Anonymous** · 07-11-2005, 01:01 PM

No I'm just wondering why a cracked head would show a higher compression with the oil test wouldn't the oil go down the cyl walls below the TDC of the piston. I don't see how the oil would go up?
Anyway does anyone know where to find piston rings for these old GSers, please don't say the dealer.

**jlmoulto** · 07-11-2005, 01:08 PM

Based on my experience with a top end rebuild, I would be certain that a valve adjustment was done first. While not a mechanic myself, I would guess that if you did a valve adjustment you may see an improvement on those numbers. The parts for a top end rebuild are fairly expensive and I would want to be certain that the rings were bad enough to be concerned about now before starting. They appear to be even and above the service level so I would personally wait.

**Anonymous** · 07-12-2005, 12:30 AM

yeah I already did a valve adjustment
I dont think if my valve where out of adjustment putting oil down would make them better that doesn't make much sense to me. thanks

**jlmoulto** · 07-12-2005, 07:37 AM

I was told, again I'm not a mechanic so take what I say with a grain of salt(!), that the oil could seal the valve if it were not seating perfectly and thus up the compression? Maybe that is totally false.

**gspaul** · 07-12-2005, 08:35 AM

The oil test for compression seal's the ring's for a few second's during the test , if the comp reading goes up, its your ring's ,if not it's valve's or valve seal's, once in a while even the head gasket!

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Are my rings Shot??? GS550E

Are my rings Shot??? GS550E

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