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leakdown-compression test readings, oil?

Started by honeybadger, January 20, 2013, 04:50:16 PM

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honeybadger

I have a '93 1200 ABS with 77k chassis miles. Indicated in the service history was a bottom/top rebuild with new valves, pistons, rings, and a .5 bore at 66k miles, but was over 9 years ago. So the bike hasn't seen a lot of road since the build.

it's too cold to get a leakdown test to show anything (I'm trying to get the inside cylinders done, but they're just too hard to reach by just taking the side covers off, and it's so cold out that the engine is cool enough to touch by the time I've got the engine at TDC and the cylinder pressurized) but without being able to ride (ice on the roads) I'm just warming the engine up between each reading and I don't think I'm getting enough metal expansion. I'm getting ~8-9% loss on the outer two cylinders.

Stethoscope reports no audible leaking from any intake or exhaust valve, and nothing from the crankcase.

Semi-cold compression test at WOT was 160-165 across the board.

The reason for all this was when I got the bike, it smoked a bit when you'd really lay into it and reach revs above 6k, but only once as you passed that point of revs, and would stop after that.

The low oil light came on (it was about 1/2qt low) while it was running 10-30 mobil synthetic and right around then I could smell smoke when I started it after about 20 minutes of cooling. I've since switched to 10-40 castrol, but I can't tell if it's completely stopped smoking, because it's been too slippery to ride. Haven't smelled/seen anything on startup.

I'm still thinking things are kosher with the engine, and that the rings just haven't got enough of a workout to finish seating? How about you guys?

The plugs have little to no deposits and aren't wet.



movenon

Is the bike new to you? Your compression sounds good to me. Without getting into oil wars I would recommend you run as close as you can to factory specs. I know its crappy weather out now but if it were me I would withhold any judgment until I ran it for a few tankfuls of fuel. A lot of bikes will smoke for awhile if they haven't been run for an extended period of time. Hopefully that's all there is to it. If the bike has siting  for a long period  without running under load then I wouldn't worry yet. Just shooting in the dark without more information. Have faith, all is fixable.
Life isn't about having the best, but about making the best of what you have...

1990 FJ 1200

Arnie

Doesn't sound like you've got any problem there, to me.

You'll find its MUCH easier to get at the plugs if you remove the tank, or even just rotate it and put it on the seat subframe backwards.

Arnie

ribbert

Quote from: Arnie on January 20, 2013, 06:12:09 PM
Doesn't sound like you've got any problem there, to me.

You'll find its MUCH easier to get at the plugs if you remove the tank, or even just rotate it and put it on the seat subframe backwards.

Arnie

Yep, this is the way, fuel lines remain attached, BUT, protect the battery terminals with a rag or something before sitting the tank across it.
Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Arnie

Sorry, my bad.  Insulating the battery is SOP, but I didn't mention it. :-(
Thanks Noel,

Arnie

honeybadger

Quote from: Arnie on January 20, 2013, 06:27:33 PM
Sorry, my bad.  Insulating the battery is SOP, but I didn't mention it. :-(
Thanks Noel,

Arnie

:rofl: yep, the bike has aftermarket additions of a radar detector and heated gear/12v outlets, so there's a rubber pad covering the battery.

I've had the bike since september, we've put about 2k miles through it. Smoking has reduced, and I thought it was gone, but after riding behind it (just before the low oil light came on) I could see small puffs of smoke when it was opened up, that weren't visible when riding it myself.

honeybadger

So the general consensus is that the engine, despite the oil burning about 1/2 qt in 2k miles when it had 10/30 synthetic, is probably doing just fine and needs more riding/heavier operating temp weight?

fj1289

Quote from: honeybadger on January 21, 2013, 01:18:26 AM
So the general consensus is that the engine, despite the oil burning about 1/2 qt in 2k miles when it had 10/30 synthetic, is probably doing just fine and needs more riding/heavier operating temp weight?

Yep, exactly...unless you are looking for a good excuse to put together a nice little 1349 with some headwork, cams, ...

honeybadger

It's already plenty enough of a rocket ship, thanks!

All I want is to be certain that it's healthy as a horse.