Honda GL1000 Smokes on Initial Startup?

Catastrophe or Nuisance?

Smoke on initial Startup 1

Greg Jones (left) and Al Wransky (right). Photo by Scott Larson

This ever happen to you?

You wheel your pristine GL1000 out of the garage and onto the driveway on a beautiful Saturday morning. You carefully do your pre-ride safety inspection.  Naturally everything checks out. You begin to put on your jacket, helmet and gloves. By this time a small audience of neighbors and kids assemble to admire your gorgeous bike.

You give a short seminar on the joys of owning and riding a fine vintage motorcycle, then mount up.  You apply the choke, check the kill switch, turn on the ignition …then punch the starter button. She fires instantly and settles into a beautifully smooth burble on the fast idle cam.  You swell with pride and satisfaction.

5 seconds later …you and your admiring witnesses disappear into a fog of dense blue smoke. What just happened here!!!

I field this question frequently. The good news is that (usually) this just a quirk of the early GoldWing engine design and nothing really to worry about. Every GL1000 I’ve ever owned or worked on has had this characteristic to some degree. My answer might not satisfy your neighbors, but it should put your mind at ease a bit.

Actually, this is the normal expectation for an engine of this vintage and technology. Why?

GoldWings have a horizontal, “boxer” engine layout. This same quirk also plagues early BMW, VW, Subaru and Porsche engines that share the boxer layout.  Ditto for Continental and Lycoming aircraft engines.

Honda employed conventional, basic piston ring technology that works quite well in maintaining compression and oil control in a running engine. But, when a bike comes to rest after being run, a certain amount of residual cylinder wall oil remains below the piston rings. During rest, a small quantity of this residual oil can seep past the piston rings. At the next startup, this tiny amount of oil will briefly produce a very impressive cloud of smoke until it burns off.

This never happens in “upright” engines due to gravity. Eventually, Honda and all other boxer engine makers devised better piston ring technology that works well to control this issue.  Case in point: modern Honda GL1800s show practically none of this bad habit.

If your smoke clears in a minute or less, your problem is just a nuisance and no real cause for concern. There is no “cure.” This is a “personality” issue that you learn to embrace. Be aware that depending on the exact location the 4 pistons actually come to rest, the problem can unpredictably seem to “come and go.:

This has actually been a recognized issue since the GoldWing was introduced.  Here is the Dealer Service Bulletin from 1975:

Smoke On Startup Service Bulletin

What can you do to lessen this nuisance ?

  • Be aware that leaving a bike on the side-stand makes the issue worse (due to gravity).
  • Leaving bike on the center-stand helps a bit.

What about persistent smoke that does not clear up?

Now you may be dealing with something more serious. Issues to investigate:

  • Low compression (piston ring / cylinder wear issue) This can be diagnosed via a compression test / leak down test.
  • Over-filled crankcase
  • Wrong oil (too thin)
  • Valve stem seals worn or brittle. This problem will give you heavy smoking on deceleration.
  • Clogged crankcase vent

 

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