An attempt to stop a GL1000 from smoking

[CYBORG]

Pretty sure on a high bank track, at speed, observed gravity is through the tire contact patch. Ever seen those old "wall of death" or giant open-grate steel ball performances?

I have seen the wall of death many times. But never with a flat four engine. I would think that centrifugal force Would work different on an engine with the pistons over the crankshaft, and one with the pistons off to the sides of it

[cfairweather]

I believe the compression will go up at least 20psi after it runs about 30 minutes on the test stand. 120 for a cold engine with new pistons, rings and valves is not too bad. I will run it for 30 minutes, remove the carbs and do the exact test and see what it does. I am guessing it will be 150psi. Not sure how accurate the Harbor Freight gauge is, but I assume it is relatively close.

[pjlogue]

Pretty sure on a high bank track, at speed, observed gravity is through the tire contact patch. Ever seen those old "wall of death" or giant open-grate steel ball performances?

I have seen the wall of death many times. But never with a flat four engine. I would think that centrifugal force Would work different on an engine with the pistons over the crankshaft, and one with the pistons off to the sides of it

I would disagree. If you think about it, centrifugal force and gravity combine to give a resulting vector force that is in vertical line with the motorcycle. Oil in the crank case is probably very close to where it would be while sitting on the center stand. Same with gas in the carburetor bowls. The only eception to this woulld be if a rider was leaned way over on the inside of a turn, I.E. hanging off the side of the bike.

-P.

[CYBORG]

Pretty sure on a high bank track, at speed, observed gravity is through the tire contact patch. Ever seen those old "wall of death" or giant open-grate steel ball performances?

I have seen the wall of death many times. But never with a flat four engine. I would think that centrifugal force Would work different on an engine with the pistons over the crankshaft, and one with the pistons off to the sides of it

I would disagree. If you think about it, centrifugal force and gravity combine to give a resulting vector force that is in vertical line with the motorcycle. Oil in the crank case is probably very close to where it would be while sitting on the center stand. Same with gas in the carburetor bowls. The only eception to this woulld be if a rider was leaned way over on the inside of a turn, I.E. hanging off the side of the bike.

-P.

I can see that. You would have to factor in speed as well

[CYBORG]

As much fun that this post has gravitated to I think we have drifted away from the original subject. Maybe we should get back to the smoking problem. My bad for causing the drift.

[cfairweather]

I ran the engine for about 15 minutes and then checked the compression. It stayed about the same, so my theory was wrong . The good news is it didn't blow up and it ran good with no issues.

[CYBORG]

good news

[cfairweather]

I am considering getting a different gauge as I am not sure this Harbor Freight one is accurate. Cliff suggested a different hose/adapter, and he might be correct.

[CYBORG]

It is a little lo, and in my opinion shouldn't be. Re check your timing, valve clearance etc. Could be the gauge I might suggest a leak down check as well

[redglbx]

All good suggestions by Cyborg, a leak down test would definitely be good but being that they’re the same on all 4 cylinders I would suspect the gauge,,, but honestly it’ll run fine probably just may not be able to beat everything with a HD tag on it. I think I’d just put it on the bike and just run it and enjoy it , but that’s me !

But those that know me would tell you that I would obsess over it until it was optimum, but age has some different effects.

[cfairweather]

It is easy for me to do any test while it is on the stand, so now is the time to check it out. I am working on one of my CB750s too. I put .50 oversized pistons in it too and am putting it back together, so I am bouncing back and forth between the two. I will try and do a leak down test after I run the engine some more. It only takes me a couple of minutes to remove/install carbs on my test engine as I have a really nice setup to make it quick and easy. I bet I can install a carb bank in less than a minute if I try.

[redglbx]

[Sidecar Bob]

FWIW, the '79 engine I had in my '83 often smoked on startup, mostly from the left side after it was parked on the side stand (separate left & right exhaust systems). After I read about tilting it to the right before parking it on the side stand it smoked a bit less. Then I added the sidecar so it was always upright and I started noticing more smoke again. And that didn't change when I changed to the '82 engine.
I'm sure it smokes more often than I notice because I'm usually on the bike facing away from the exhaust when I start it, with no reason to look in the mirrors until I'm off of the driveway and it has stopped by then.
I don't know what the neighbours think about it, though.....

BMW's K bikes have all of the cylinders horizontal and pointing to the left. When they were first introduced they were notorious for smoking on startup if the side stand was used. I read an article at the time that explained that it was caused by the rings moving around in their grooves so that when the gaps lined up on the bottom a tiny pinpoint sized drop of oil could enter the combustion chamber and cause a huge cloud and with all cylinders on the left that happened fairly often.
IIRC, the solution was to add bumps in the piston ring grooves and notches in the rings so that they couldn't move around. I've occasionally wondered why Honda didn't do something similar, usually when there are neighbours outside when I start it up

[dontwantapickle]

It only takes me a couple of minutes to remove/install carbs on my test engine as I have a really nice setup to make it quick and easy.

Pics?

[cfairweather]

I will take a few pictures tomorrow. It isn't fancy, but it works. I leave the intakes mounted to the engine and the vacuum gauges stay attached too. I will explain this tomorrow if I have time. Today, I noticed oil is dripping out of the water pump weep hole, so I ordered a new water pump.