ET: Engine (Twin) Fogging for Mosquitos; Valve Guide Issues and Solutions

ClassicBiker

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VOC Member
A curious thing happened to my Shadow this past Tuesday. Before going to our monthly section meeting I started the Shadow and warmed it up. I looked and checked that I had a nice steady oil return, I did. I warmed up the bike and rode the 22-24 miles to the meeting and parked the bike for a couple of hours. After the meeting the bike fired right and I rode away. After going a few mile I had to stop for a light and a cloud of oily smoke blew past me from behind. I looked down and back only to see that I was fogging for mosquitos! :eek: If the smoke pouring out was horrendous. There was smoke pumping out the breather even.:( Crossing my fingers and praying quietly to myself I continued on, hoping the oil would last and the engine wouldn't seize. Well I made it home without further issues. I checked the oil in the tank and it wasn't down too much from when I had left home. Wednesday morning I pulled the plugs and the valve covers to see if I could determine if it was one or both cylinders oiling (both) and if a there was an issue with the valve gear (doesn't seem to be) so I put everything back and started it up. It smoked from the exhaust and oil and vapor dribbled from the breather for about ten or so minutes and then just quit. o_O Now I had the tank cap off and was watching that oil returned (it was) then all of a sudden the volume of oil exiting the return dramatically increased for a few moments and returned to normal, that was when the problem stopped.
Never having had this happen before, is this indicative of wet sumping? If it is, what would cause it to happen in this fashion, in the middle of a ride and not immediately upon start up after sitting for awhile?
Any thoughts or suggestion greatly appreciated.
Thanks
Steven
 

Simon Dinsdale

VOC Machine Registrar
VOC Member
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If it had smoked when you first started the bike on the Tuesday in question before going to the section meet I would have said it was due to the bike having sumped whilst in the garage. As it didn't start smoking until later that night after you had done 25+ miles I would say the oil level built up in the sump due to it not returning to the tank properly and most probably due to the return pipe to the tank been partially blocked with something.
Just a guess
Simon
 

ClassicBiker

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VOC Member
If it had smoked when you first started the bike on the Tuesday in question before going to the section meet I would have said it was due to the bike having sumped whilst in the garage. As it didn't start smoking until later that night after you had done 25+ miles I would say the oil level built up in the sump due to it not returning to the tank properly and most probably due to the return pipe to the tank been partially blocked with something.
Just a guess
Simon
maybe fungus under the flywheel.

I think you both might be correct. "Fungus" under the flywheel temporarily blocking the return pickup. When this was going on the oily mess coming out of the breather resembled grey mayonnaise like stuff created when a water cooled engine blows its head gasket and the coolant and oil mix. It was rather curious to see this stuff dribbling out of the breather pipe, because unless I've completely missed the plot I believe my Shadow is air cooled and not water cooled.:rolleyes::confused: Now what concerns me is if some "fungus" (for lack of a better term) was blocking the pickup it didn't get blown out through the breather as that isn't an active pump as such, but must have been picked up by the return and dumped back into the tank.:eek:
Time for an oil change I think.

Check to see if the breather pinion is still an assembly.
I shall do that. I had wondered if something was amiss with it. So I ran the engine with the ATD cover removed, thinking that would allow the engine to breathe easier. It still smoked and dribbled. So I let the engine cool and then replaced the ATD cover and ran it again and that's when it cleared. I'll report back on what I find.
Steven
 

b'knighted

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Decades ago I ran a Comet with its ATD cover removed and was surprised at just how much oil was thrown out. I forgot all about this until recently when I ran a different Comet with its ATD cover removed and was again surprised at just how much oil was thrown out. I won't do it again. Do twins not normally dump and spray oil out when run without the cover?
 

mercurycrest

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VOC Member
I agree with Ian, you should have had oil all over the place! You might like to check how much oil is in the return line at the front ex. valve fitting. The "mayonaise" is condensate... You need to ride it further and properly warm the engine up. ;)
 

ClassicBiker

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VOC Member
Decades ago I ran a Comet with its ATD cover removed and was surprised at just how much oil was thrown out. I forgot all about this until recently when I ran a different Comet with its ATD cover removed and was again surprised at just how much oil was thrown out. I won't do it again. Do twins not normally dump and spray oil out when run without the cover?
Not much it didn't. I didn't completely remove it though. I backed off the six screws and it pulsated a bit like a one way valve. A lot of oil vapor came out though. It has me thinking about the pros and cons of something like the elephant trunk breather with/without a one way valve and a catch can.
Steven
 

ClassicBiker

Well Known and Active Forum User
VOC Member
I agree with Ian, you should have had oil all over the place! You might like to check how much oil is in the return line at the front ex. valve fitting. The "mayonaise" is condensate... You need to ride it further and properly warm the engine up. ;)
I agree it's condensate and that I should ride it further and more.:D But the fact of when it happened is what perplexes me.:confused: That that is persisted through till the next day and cleared inexplicably is what worries me. :( When I removed the front rocker cover there wasn't an inordinate amount of oil present nor was it starved for it either. This is what mystifies me. I have some old nasty looking rocker covers that I might modify with window to see the oil flow in the rocker areas.
Steven
 
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