This isn't a how-to article, nor is it (exactly) a plea for help although anyone who can provide definite guidance / information is welcome to chime in. It's more in the way of a public musing along with a cautionary tale for anyone with a similar problem.
BACKGROUND
A few weeks ago I did the scheduled 64,000 mile valve clearance check on my 2004 ST1300. All is well on that front- everything is within spec.
During reassembly I tried to be careful not to trap the rubber mat that sits behind #4 between the head and the head cover, and I *think* I was successful. I ran the engine for a couple minutes just to verify that it would not explode or immediately catch fire. So far so good, and without massive leaks, so I buttoned everything up and declared "Job done."
My first ride after the service was about 250 miles with no *apparent* issues.
PROBLEM
HOWEVER, the *next* ride (actually, rides- WV-STOC) revealed that *something* was not right.
Each morning when I started the bike it smelled hot for a few moments and produced a thin wisp, unmistakable as oil smoke, that dissipated after a moment.
Ruh roh, Rorge, you've got Trouble somewhere.
It never persisted, and a check of the sight glass showed the oil level as actually slightly TOO full. (This photo was taken 30 minutes to an hour after the engine had been run, this morning. When I first checked it, with the engine stone cold, the level was somewhat above the top index.)
Neither the hot smell nor the wisp of smoke recurred after the engine was shut off for rest / meal stops, or if they did it was momentary and fleeting and not enough to draw my attention to it.
This morning I pulled all the bodywork and, sure enough, there was a telltale smear of oil, and even a droplet, along a section of the #1 exhaust header. It seems obvious that that is the source of the *smoke* and the hot smell, but what isn't (yet) so apparent to me is the true *source* of the leak.
My first hunch was that I had not gotten gasket sealer well applied on the half moons of the gasket between head and cover when reinstalling the head covers after the valve clearance check, but there's no tell-tale trail of oily dirty ooze from either of them, on either side. In the photo below I'd have expected to see some sort of trail along the paths of the arrows, but it wasn't there (even before I cleaned the front of the engine block). The trio of bolts at the bottom of the photo did have a suspicious accumulation of crud, however, and the oil on the header pipe was directly beneath the lowest of them.
So I pulled the head cover and sure enough, the half moons did not seem to have full coverage of sealant. Also, although I had been mindful of the rubber sheet at the back of the right side head cover I had forgotten about / overlooked the rubber mat along the top of the left side. It appears to have gotten pinched in the top of the head cover.
There's now a new application of gasket sealer FULLY around the half moons, and the rubber mat is definitely NOT caught in between the cylinder head and the head cover. I've run the engine again for several minutes under light load (put it in gear and held the throttle open to spin the engine at 2,000 RPM for a couple minutes) and am now waiting for things to settle a bit before I check again.
I also found accumulations of oil / grit all along the bottom of the oil pan (in between the fins); it is heavier on the right side. After cleaning the engine casing and running it then shutting it down and letting it sit for a spell, and before I fixed the left side issues, I found a trail of oil along the right front edge of the engine.
So, where is *THAT* coming from? The trail on the front engine cover was created while the bike was running on the center stand, although the mess on the engine block and in the fins of the oil pan was there already (from whatever leak there is; it's new and not a legacy buildup from previous leaks).
I *think* the right side head cover gasket half moons had adequate sealant applied, based on the residual mess on the front of the engine (disgraceful), and I have double-checked that the rubber mat at the back is not pinched in between the cover and the head. I have also checked that the rubber mat along the top of the right side head cover is not pinched, as it was on the left side. And, there is no trail of seepage on the front of the block. Finally, any leak from the area of the cylinder head cover would be well behind the front of the engine and there is no evidence of a seepage trail connecting the two areas.
Is it possible that the (postulated) leak from the pinched mat on the left side put oil into the V (abyss), which then found its way to the right side of the engine? Or perhaps it got there via the small channel that separates the "Honda" logo cover from the rest of the front of the engine? (Highlighted red line in the photo below.) That channel continues upward and across the engine all the way over to the left side. *Could* oil be coming from the left side along / through that channel to end up dribbling down the right hand side and into the handy "catch pan" of the lower fairing? If that *isn't* the source, I have no further speculations.
Finally, the last place I found significant oil accumulation was the back end of the inner side of the main cowling on the left side. Unless it got blown in there by the combined action of wind while riding , along with the radiator fans, I have absolutely zero hypothesis as to how it got there. I've cleaned it up and will continue to monitor that area over the next several times when the tupperware is off. I may also try to watch the lower fairings for a while to see whether there's any indication of renewed buildup there, though I'm not overly sanguine about the odds of figuring out where it is coming from.
So, I *think* I have found and fixed one problem; the question remains as to whether that was the *only* issue. Only time will tell. In the meantime, after having run the engine again for several minutes I'll let it sit (the yard needs mowing in the meantime) and make one more examination before I start the wrestling match that inevitably occurs when I try to reinstall all the bodywork...
BACKGROUND
A few weeks ago I did the scheduled 64,000 mile valve clearance check on my 2004 ST1300. All is well on that front- everything is within spec.
During reassembly I tried to be careful not to trap the rubber mat that sits behind #4 between the head and the head cover, and I *think* I was successful. I ran the engine for a couple minutes just to verify that it would not explode or immediately catch fire. So far so good, and without massive leaks, so I buttoned everything up and declared "Job done."
My first ride after the service was about 250 miles with no *apparent* issues.
PROBLEM
HOWEVER, the *next* ride (actually, rides- WV-STOC) revealed that *something* was not right.
Each morning when I started the bike it smelled hot for a few moments and produced a thin wisp, unmistakable as oil smoke, that dissipated after a moment.
Ruh roh, Rorge, you've got Trouble somewhere.
It never persisted, and a check of the sight glass showed the oil level as actually slightly TOO full. (This photo was taken 30 minutes to an hour after the engine had been run, this morning. When I first checked it, with the engine stone cold, the level was somewhat above the top index.)
Neither the hot smell nor the wisp of smoke recurred after the engine was shut off for rest / meal stops, or if they did it was momentary and fleeting and not enough to draw my attention to it.
This morning I pulled all the bodywork and, sure enough, there was a telltale smear of oil, and even a droplet, along a section of the #1 exhaust header. It seems obvious that that is the source of the *smoke* and the hot smell, but what isn't (yet) so apparent to me is the true *source* of the leak.
My first hunch was that I had not gotten gasket sealer well applied on the half moons of the gasket between head and cover when reinstalling the head covers after the valve clearance check, but there's no tell-tale trail of oily dirty ooze from either of them, on either side. In the photo below I'd have expected to see some sort of trail along the paths of the arrows, but it wasn't there (even before I cleaned the front of the engine block). The trio of bolts at the bottom of the photo did have a suspicious accumulation of crud, however, and the oil on the header pipe was directly beneath the lowest of them.
So I pulled the head cover and sure enough, the half moons did not seem to have full coverage of sealant. Also, although I had been mindful of the rubber sheet at the back of the right side head cover I had forgotten about / overlooked the rubber mat along the top of the left side. It appears to have gotten pinched in the top of the head cover.
There's now a new application of gasket sealer FULLY around the half moons, and the rubber mat is definitely NOT caught in between the cylinder head and the head cover. I've run the engine again for several minutes under light load (put it in gear and held the throttle open to spin the engine at 2,000 RPM for a couple minutes) and am now waiting for things to settle a bit before I check again.
I also found accumulations of oil / grit all along the bottom of the oil pan (in between the fins); it is heavier on the right side. After cleaning the engine casing and running it then shutting it down and letting it sit for a spell, and before I fixed the left side issues, I found a trail of oil along the right front edge of the engine.
So, where is *THAT* coming from? The trail on the front engine cover was created while the bike was running on the center stand, although the mess on the engine block and in the fins of the oil pan was there already (from whatever leak there is; it's new and not a legacy buildup from previous leaks).
I *think* the right side head cover gasket half moons had adequate sealant applied, based on the residual mess on the front of the engine (disgraceful), and I have double-checked that the rubber mat at the back is not pinched in between the cover and the head. I have also checked that the rubber mat along the top of the right side head cover is not pinched, as it was on the left side. And, there is no trail of seepage on the front of the block. Finally, any leak from the area of the cylinder head cover would be well behind the front of the engine and there is no evidence of a seepage trail connecting the two areas.
Is it possible that the (postulated) leak from the pinched mat on the left side put oil into the V (abyss), which then found its way to the right side of the engine? Or perhaps it got there via the small channel that separates the "Honda" logo cover from the rest of the front of the engine? (Highlighted red line in the photo below.) That channel continues upward and across the engine all the way over to the left side. *Could* oil be coming from the left side along / through that channel to end up dribbling down the right hand side and into the handy "catch pan" of the lower fairing? If that *isn't* the source, I have no further speculations.
Finally, the last place I found significant oil accumulation was the back end of the inner side of the main cowling on the left side. Unless it got blown in there by the combined action of wind while riding , along with the radiator fans, I have absolutely zero hypothesis as to how it got there. I've cleaned it up and will continue to monitor that area over the next several times when the tupperware is off. I may also try to watch the lower fairings for a while to see whether there's any indication of renewed buildup there, though I'm not overly sanguine about the odds of figuring out where it is coming from.
So, I *think* I have found and fixed one problem; the question remains as to whether that was the *only* issue. Only time will tell. In the meantime, after having run the engine again for several minutes I'll let it sit (the yard needs mowing in the meantime) and make one more examination before I start the wrestling match that inevitably occurs when I try to reinstall all the bodywork...
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