An attempt to stop a GL1000 from smoking

[redglbx]

Bob, the smoking with the sidecar is very interesting, really makes you wonder why. I always wondered about the BMW’s smoking , I’ve seen the older twins smoke on startup particularly onthe lh side but never the cloud like our GL’s …

On the pistons, I was always told and read that starting in the 78-79 years Honda clicked the ring gaps to reduce the start-up smoke and I believe that they are better than the 75-77’s , maybe not gone but better. Also I remember the magazines talking about Honda putting pins or bumps in the ring grooves because just clocking the rings didn’t eliminate the smoke because they found the rings rotate as the engine runs……..but I don’t know if all that’s true. Very interesting conversation here !

[robin1731]

Rings do rotate on the pistons. Valves and valve springs also rotate. A lot more movement goes on in a running engine than some people think.

[cfairweather]

Here are a few pictures of my test stand. Let me explain:

1. I use an electric fuel pump and the fuel line is routed under the carb, so all I have to do is attach it.
2. I removed the rubber from the intakes and leave them mounted on the engine. I cut a radiator hose to just the right length where the carbs can slide into place and then are secured with hose clamps. The hoses stay attached to the intakes on #2 and #4. The carbs will slide into these two intakes. Before I slide the carbs into #2 and #4, I place the rubber hoses over the #1 and #3 carbs so they will clear the #1 and #3 intake tubes. After the carb bank is in place, I slide the hoses over the intakes and and clamp them.
3. I have a single throttle cable that I quickly attach and only get it finger tight.

[redglbx]

I bet it rides great !. Good job Cedric!

[gltriker]

20250426_152340 (2).jpg

[redglbx]

Cliff, I agree ! WishI could open your attachment though.

[cfairweather]

I have to say, I don't believe my gauge. After I ran the engine for about 15 minutes, the compression should have been much higher. The machine shop set the piston clearance to the minimum in the manual, so this should have a lot of compression. I should receive a new water pump on Friday, so I will test some more after I install it.

[gltriker]

Cliff, I agree ! WishI could open your attachment though.

red'- Its just a very greatly reduced copy of the GL1000 cylinder head chambers' photo I utilized to perform the CC's testing in my last *show and tell* session
I wished to not post a full blown link to that session... a too eager teaser for other unaware participants?

[gltriker]

I have to say, I don't believe my gauge. After I ran the engine for about 15 minutes, the compression should have been much higher. The machine shop set the piston clearance to the minimum in the manual, so this should have a lot of compression.

minimum 160psi - with a proper 12mm adaptor and an accurate pressure gauge
Maybe another 5 or10 psi with the cylinder head and cylinder block resurfacing taken into account.

[redglbx]

Cedric, it could very well be the gauge, A precision instrument gauge accuracy is typically +/- 1% of full scale but I can garuntee that is not an instrument grade gauge so would have an accuracy rating of +/- 10% of full scale. Instrument grade gauges are used to check & calibrate “normal” gauges and being a Harbor Freight gauge it’s probably from China and I would question whether or not it meets the +/-10% NIST standard, probably not.

That’s why it’s more important that they are consistent rather than the actual number. I have literally tested & calibrated hundreds of gauges and can say that I don’t really put much stock in “the numbers”, and I can also say that you can spend a ton of money and still get a crap gauge.

A quick story is that I setup a test fixture for quick testing of gauges on a bench in my lab and when the word got out there was a parade of people coming in to check their tire pressure gauges, the variation was amazing.I even had an Engineering Co=op who spent a ton of money on a gauge for setting air pressure in drag slicks where a 1psi adjustment is important. His gauge was absolute shite and he ended up screaming at me because 10k checking station had to be wrong even after I showed him it was good with a calibration standard (+/- 1% of full scale) which the test setup I had used all calibration standards parts.

Anyway, if it runs good I wouldn’t worry about it too much. If you just have to know and buy a new gauge then I’ll ask you “which one is correct?”

[cfairweather]

That is excellent advice. I never have worried about compression, so why start now .

[redglbx]

One more thing I’ll add to this thread is about oil usage….. The only time my 76 ever used oil was on a CWC homecoming trip of over 300 something miles. Most all of which was on a toll road where I was consistently running over 4K rpm (hard on fuel economy) , I had gone through things prior to leaving with the usual oil change and check the valves and carb balance.

So, on the group ride we stopped for fuel and I wanted to check the oil level which is difficult for an old guy since you need to get on you hands & knees. And since I keep the oil level at the top of the window you need to work the wiper to make sure there is oil in there. Well shite after a short bit I realized there was no oil in the the window after around 375-400mi. I went in and got a quart of oil (can’t be that low right?) it hadn’t been smoking but it drank that whole quart and still nothing in the window,,, shite,, went and got another quart, drank that as well with nothing in the window,, I got a 3rd quart which gave me a little in the window while a 4th quart brought it back up to the top of the window,,,,shite!

So now I’m just freaking out, what the heck’s going on ? It’s running perfectly fine,,,, so I go over everything since I had taken things apart at home ,,,, the only thing I found wrong is that I forgot to plug the crankcase breather back into the air cleaner so I plugged it back in and worried the rest of the weekend. I bought some extra oil to carry and was figuring I must’ve broke a ring or something figuring I’d be replacing the engine once I got home..

Well I hasn’t used another drop of oil since, it was because of the crankcase breather being unplugged, which I think is because w/o that it allows the crankcase to build pressure and allows the rings to flutter and oil to pass , I have since made it a point to rebuild the oil separation can on the back of the motor and have made a serious effort to make sure there are no vacuum leaks in that system. Over the years since I have seen a number of bikes with a small K&N filter on the crankcase breather line, bad idea,, makes me cringe but generally I keep my mouth shut… generally. My .02

[cfairweather]

The engine is an "air compressor" and it has to breath. Good point Steve.

[redglbx]

Yepper Cedric, it was fashionable for a long time to eliminate the crankcase breather by just using a small filter on the hose since it was all about the “evil” emissions control stuff. Most of it like this example have a real purpose that is bad to eliminate.

Like I said above my 76 hasn’t used a drop so long as the breather system is hooked up & functioning. It also provided a bit of a bump in fuel economy, not much but measurable.

On your compression, the fact that it’s the same across the board is far more important than an actual ego boost number. I went down that path looking for max performance and my 76 makes way more power than it did new but it really doesn’t make any difference unless you pull the throttles fully open.

The point was driven home for me when my buddy with the 76 with the low 85psi compression was just tooling along next to me on the toll road at 70-80mph not lacking any power and getting slightly better fuel economy vs my 190-200psi compression motor,,,just a sweet running thing ! And just like mine it just effortlessly accelerates up to speed.

[CYBORG]

I use a crankcase filter on my78, and do not have the oil use you mention. I have it mounter above The crankcase far enough to prevent oil from getting to it. And a large enough hose to prevent pressure build up. Have not had a problem with il lose.