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Discussion Starter #1










Does anyone recognize this gunk? I've seen it both times at the last two changes after going to Mobil 4T Racing 10W40.



It feels like moly grease, smears with no perceptible grittiness at all, and cleans up with a brushstroke with some kerosene. There is no other junk in the filter except a tiny amount of small flakes and sometimes a whisker.



The engine is running fine. I'm thinking it could be from the oil carbonizing during the occasional high temp/low speed trail section.
 

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One possibility is that it's RTV.



Done any work involving side cover removal or gasket replacement lately?



Some high detergent oil can shake some pretty weird stuff loose, but running any oil before RTV has fully set can result in similar looking deposits.
 

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Discussion Starter #3
One possibility is that it's RTV.



Done any work involving side cover removal or gasket replacement lately?



Some high detergent oil can shake some pretty weird stuff loose, but running any oil before RTV has fully set can result in similar looking deposits.


Nope, no work like that done....if it was RTV, it would not smear like a grease or be cleaned by one swipe with a kerosene loaded brush, unless it was less than 6 hours old, (even then).....at least in my experience.
 

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Seems like I read one time about some kind of coating on the inside of the cases, or something like that coming loose. But you're right, from your description it seems more petroleum based.



Found it here. Probably a long shot.
 

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Seems like I read one time about some kind of coating on the inside of the cases, or something like that coming loose. But you're right, from your description it seems more petroleum based.



Found it here. Probably a long shot.


Man, I'd forgotten all about that. I don't think we ever nailed down what years had the coating. I've never seen it inside any TW I've worked on yet.
 

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Possibly the detergent in the oil is loosening up carbon build up in the top of the head? Back when i ran Hondas in the woods my engine builder recommended running synthetic oil due to the fact that when you shut down a hot bike engine the dino oils can burn, break down, and build up crud around the valves and cams from the heat. common problem on the older honda RFVC 4 valve engines
 

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Possibly the detergent in the oil is loosening up carbon build up in the top of the head? Back when i ran Hondas in the woods my engine builder recommended running synthetic oil due to the fact that when you shut down a hot bike engine the dino oils can burn, break down, and build up crud around the valves and cams from the heat. common problem on the older honda RFVC 4 valve engines


Hmmn, so I could be seeing carbon from the first 2000 miles of running dino oil? I remember now that this is the FIRST oil change after going to synthetic at 2000 last fall. (I know, I know, I should have changed it out in May even though it only had 300 miles over the winter.)



However, I did see some of this stuff in the filter last fall, and that too was only a 1000 mile interval. I just don't put enough miles on the bike, so I change it spring and fall, regardless of mileage.



What we called "coking" of the oil is very common in aircraft engines, particularly turbochaged ones, if you didn't perform a two or three minute cooldown at idle. However, it looked more like coffee grounds and could be crushed between the fingernails.



This stuff sure does look, feel, and act like carbon buildup, though, and thus the synthetic is doing it's job....I'm not about to pull the head to find out, but I will be using 1,000 mile changes for a while to see what happens.
 

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In your original post you said it felt like moly grease with no grittiness. That would be RTV, probably from initial factory assembly given your low miles.



If it's gritty and it persists beyond your next oil change it's most likely clutch material.
 

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.I'm not about to pull the head to find out...........................


Maybe you can just take off the valve cover and see what needs to be seen.



BTW, I found RTV in my other TW and it didn't look anything like that. It was in small thin sheets, firm, and non-spreadable.
 

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Discussion Starter #11
Maybe you can just take off the valve cover and see what needs to be seen.



BTW, I found RTV in my other TW and it didn't look anything like that. It was in small thin sheets, firm, and non-spreadable.




I had the valve covers off for adjustment 5 hours before the oil change, everything in there was spick and span.




No, there is no way this could be RTV.



EDIT:



It just occurred to me that there is another place in these engines where it can get hot enough to carbonize oil, and that is the clutch. There have been times when I have had to slip the clutch in 1st going up some nasty single track. I didn't think that 10 or 15 seconds of slipping at moderately high RPMs would abuse the clutch that much, but it is one other possibility. Maybe I should just have a look at the oil filter after such an episode.
 

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Which do you have?



That much grit at every oil change is not normal.



RTV if put below oil level before it sets will never harden. It resembles moly grease. Floats around in there like jelly indefinitely. That's what you described in your initial post. Doesn't sound like your latest description, but it happens a lot.



If it's allowed to set up before it's put into use the excess eventually comes off in little ropes. After a few hundred trips through the tranny gears it segments into somewhat consistent hard gray or black grit, mostly flat. Gray factory RTV is often mistaken for metal, black for carbon. Carbon or hardened RTV has little weight and stays in suspension. It will usually be eliminated within an oil change. It will almost always diminish to nothing with mutiple oil changes. You usually see this in new bikes within the first couple thousand miles or on bikes which have recently had work done by "book time" mechanics or sloppy backyard types.



Clutch binder material looks similar but has some weight. It tends to settle in the nooks and crannies of the lower cases and lies in wait. Bits of it constantly deposit in the oil filter (if you're lucky). When a big chunk of it shakes loose, byebye Mr. Motor. Other than the cam chain tensioner nothing else in your motor contains enough material to continue depositing its parts and pieces indefinitely.



If it ain't metal it has to be one of the above.
 

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Discussion Starter #13
Which do you have?



That much grit at every oil change is not normal.



RTV if put below oil level before it sets will never harden. It resembles moly grease. Floats around in there like jelly indefinitely. That's what you described in your initial post. Doesn't sound like your latest description, but it happens a lot.



If it's allowed to set up before it's put into use the excess eventually comes off in little ropes. After a few hundred trips through the tranny gears it segments into somewhat consistent hard gray or black grit, mostly flat. Gray factory RTV is often mistaken for metal, black for carbon. Carbon or hardened RTV has little weight and stays in suspension. It will usually be eliminated within an oil change. It will almost always diminish to nothing with mutiple oil changes. You usually see this in new bikes within the first couple thousand miles or on bikes which have recently had work done by "book time" mechanics or sloppy backyard types.



Clutch binder material looks similar but has some weight. It tends to settle in the nooks and crannies of the lower cases and lies in wait. Bits of it constantly deposit in the oil filter (if you're lucky). When a big chunk of it shakes loose, byebye Mr. Motor. Other than the cam chain tensioner nothing else in your motor contains enough material to continue depositing its parts and pieces indefinitely.



If it ain't metal it has to be one of the above.


But the material I'm describing does not have the slightest gritty or sticky feel to it, it's smooth as butter and about as resistant to solvent, although it appears lumpy in the photo. One swipe with a brush or cloth soaked in kerosene and it's gone. So if this is unset black RTV, why did it wait until 7 months and 2,000 miles to start appearing? I've seen plenty of unset RTV, and given this gunk's extremely easy removal from the screen, I just can't believe it's RTV....any RTV I've ever used required lacquer thinnner or acetone for cleanup, and much more than one quick swipe. (But then, I never squeezed any into some hot oil and put in in a Cuisinart to see what happened.
)



I wasn't thinking about actual clutch plate material so much as just burnt oil...but synthetic isn't supposed to burn like dino oil.



I just checked the filter today and there was a small amount of it again, about 200 miles after the oil change, which included some gnarly, slow 1st gear clutch slipping ball bearing rock sections...(God, I hate what ATV's do to rocky trails, they just seem to deposit all the rocks in the tire tracks
)



I'm just going to clean the filter every 500 miles for a while, it only takes ten minutes.
 

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This is from the mobil 1 site might offer some insight. Switching From Conventional Motor Oil to Mobil 1

There seems to be confusion about how to make the switch from conventional motor to synthetic. I am a do-it-yourselfer. Could you provide instructions?

-- Joe D., Miami, FL



Answer:

The instructions are very easy to follow: Simply change the oil as you would normally. Any “confusion” is just myth. You can switch from conventional motor oil to Mobil 1 synthetic (and back again, if you want), without following any special procedures.



The only exception to this is with a higher-mileage engine that has never used synthetic motor oil, or with an engine that has used conventional motor oil and been poorly maintained. In these cases, you should still follow the same basic oil-change procedures (drain the old oil, remove the old oil filter, put in new Mobil 1 and put on a new oil filter), but you should follow a regimen of one or two shortened oil-change intervals. For instance, let’s say that your regular oil change interval is 5,000 miles. If you’re switching to Mobil 1 under the circumstances mentioned above, make your next Mobil 1 oil change in 2,500 miles, your third Mobil 1 oil change 3,500 miles after that, and then follow your normal 5,000 mile oil-change interval. The reasoning behind this staggered interval is that a high-mileage engine, or one that has seen infrequent oil changes, will likely have a considerable build-up of sludge and deposits. Mobil 1 will help clean the engine as you drive, but it will have to work much harder in a very “dirty” engine, and so it is best to change the oil more frequently for those first few thousand miles. After that, you can rest assured that Mobil 1 is continuing to keep your engine running clean and well lubricated for mile after mile.
 
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