Rings?

[Guest]

Still learning my way around the GS750 engine (and infernal combustion engines in general). Right now I'm wondering if I may have a ring problem.

In several places where it's necessary to turn the crankshaft by hand, I've read that one should remove the spark plugs so one won't have to fight compression in the cylinders.

When I checked my ignition timing a couple months ago, I didn't bother removing the spark plugs and was still able to turn the crank with a box wrench. Is it likely I'll need to replace the rings sometime soon? I still need to check the valve clearance, and the carbs are getting a bath after that. But I'm just wondering if there'll be some ring work down the road.

I'll get a compression gauge eventually and check it properly, but I'm just curious if this might be a bad sign.

[Nessism]

First things first. Adjust the valves and do the carbs. Check the Newbie Mistakes link in my signature while you are at it.

[Steve]

Don't take it as a bad sign quite yet.

When did the bike last run? I get the impression that the bike is new to you, have you run it?

If you have not run it, how long was it sitting before you got it?

Because these old bikes are usually lavished with copious quantities of neglect (before we get them), it's possible that the rings are just stuck in the pistons and not making a good seal on the cylinder walls. Also, there might be a light coating of surface rust on the cylinders, which does nothing to enhance compression numbers.

The bike will probably start and run just as it is. After running it about 100 miles, change the oil to get any built-up crud out, then run it for several hundred more before checking the compression. It helps if you give it large doses of throttle and RPM while doing this, just to give the rings every reasonable chance possible of getting free.

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[tkent02]

Even with tight compression it's really not all that much harder to turn the engine with a wrench. No big deal either way.

[Hinermad]

Don't take it as a bad sign quite yet.

When did the bike last run? I get the impression that the bike is new to you, have you run it?

If you have not run it, how long was it sitting before you got it?

Thanks, I don't feel quite so worried now.

It's fairly new to me. I bought it in July. I've had it on the road a few times but the acceleration is pretty lackluster (0-60 measured in minutes) and idle drifts all over the place. I've probably put 100 miles on it since I got it. It doesn't have enough get-up-and-go that I'd trust it for the drive to work.

The previous owner did regular oil changes but his idea of winter storage was a dose of Sta-Bil in a full tank and park it in the garage for five months. So I know the carbs need some TLC and it's probably overdue to have the valve clearances checked.

Riding season here is nearly over, so I'll drain the tank and carbs and prep it for winter. There should still be some decently warm days and I'll try to get the valves checked then. Next spring I'll change the oil and pull the carbs and scrub them out, then see how it behaves. (I've already got an O-ring kit for it.) I'll still get a compression gauge and check it, but I'll put some more miles on it after the other work is done first.

Thanks again for the advice, everybody!

[Steve]

The only change I would make to the PO's winterizing routine would be to put a DOUBLE dose of Sta-Bil in the tank.

Please be aware that if you drain the tank, it stands a good chance of building condensation. You will be better off if you treat the gas and fill the tank.

It is also better to change the oil BEFORE storage. Look at it this way: let's say the oil is a bit 'contaminated' and has a small drop of undissolved acid that just happens to be stuck on the crank or the cam when you stop it. That acid will have all winter to slowly eat away at whatever metal it is touching. Better to start with fresh oil to avoid that.

When you pull the carbs, there is more to cleaning them than "scrubbing them out". Follow THIS GUIDE to clean them properly.

Valve adjustment is also better to do somewhat sooner than later. Valves always tighten up, tight valves make the bike harder to start and can be damaged by burning much easier. Proper valve adjustment will avoid that, and the bike will be ready for a ride, when you get occasional warm day after the snow melts.

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[Hinermad]

The only change I would make to the PO's winterizing routine would be to put a DOUBLE dose of Sta-Bil in the tank.

Please be aware that if you drain the tank, it stands a good chance of building condensation. You will be better off if you treat the gas and fill the tank.

Okay, that's what I thought but I've more recently been told to drain it. (But then that was by someone in Florida, where condensation is less likely to happen. Upper New York has very different weather.) I use Seafoam to winterize my lawn mower and summerize my snowblower. Would that be all right for the bike too?

I was planning to follow the instructions in that file when I pull my carbs. "Scrubbing out" is just easier to type.

Thanks for the advice!