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Post by philmill on Nov 16, 2021 12:13:01 GMT 1
Hi guys, can any post some pictures of 31k bottom engine case? Both inside and out. I’ve got an oil leak and it looks like I’ve got a problem, I can’t tell from trying to take pictures where the leak is coming from. It’s is not the hole that drains from the top, that much I know. Thanks, Phil   |
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Post by philmill on Nov 16, 2021 12:21:04 GMT 1
Just think about this, could it be where the crankshaft locating pegs are? And if so surly it should not leak? If it’s leaking oils there it must be drawing air!
Phil
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Post by oldbritguy on Nov 16, 2021 13:11:04 GMT 1
Crank locating pegs are on the bearings which lock in the notches at the front where the top and bottom cases join. Side float is taken up by the half ring on the bearing. Unsure about other pegs.
I have a set of cases in the hut which I’ll dig out tonight Phil and take some pics.
Do you think you have a leak up inside the webbed area below the crankshaft itself?
How bad is the leak and is it oil or fuel?
Hopefully an easy fix
John
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Post by midlifecrisisrd on Nov 16, 2021 14:24:01 GMT 1
I know what you mean about the crank locating pegs
That isn't what they are but there are partial holes in the bearing recesses that have dimples below them on the lower case
It is rare but it has been known for them to go porous after vapour blasting
Try squirting the area with carb cleaner, waiting till it vaporized then smear with super glue to seal the surface
Steve
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Post by Tobyjugs on Nov 16, 2021 14:46:39 GMT 1
I've have a leak in this place I just cleaned the dimple prepped it and added more liquid metal. I used Wencom for no other reason than I can get it for free.
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Post by philmill on Nov 16, 2021 15:07:45 GMT 1
I wondered about using something like JB weld, i guess engine out and turn it upside down is easier than a full strip!
Phil
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Post by midlifecrisisrd on Nov 16, 2021 16:32:57 GMT 1
I wouldn't take it out
Clean, dry, and blob 😁
Nothing lost if it doesn't work
Steve
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Post by markhoopy on Nov 16, 2021 18:23:02 GMT 1
I wondered about using something like JB weld, i guess engine out and turn it upside down is easier than a full strip! Phil Looks from the comments that you might not need this now but just in case ..  |
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Post by muttsnuts on Nov 16, 2021 21:14:23 GMT 1
the leak will be coming from the dowels, these are holes used during the casting process, they are then blanked off using dowels, originally they are sealed in place, but over time and with vapour blasting the sealant can be degraded, so they start to weep as mentioned above, the best course of action is as mentioned above, just use some JB weld or the likes to seal them back up - no need to take the engine out, just mix the JB weld so its a little stiffer than normal and put on the dowel points, can be a tad tricky as they are deep into the casting, but doable - be sure they are really clean and free from oil/grease etc
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Post by oldbritguy on Nov 17, 2021 8:29:19 GMT 1
   I think the guys have explained this Phil Cases not as good as Mark's but another view to consider John |
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Post by chrisg on Nov 17, 2021 9:45:29 GMT 1
the leak will be coming from the dowels, these are holes used during the casting process, they are then blanked off using dowels, originally they are sealed in place, but over time and with vapour blasting the sealant can be degraded, so they start to weep as mentioned above, the best course of action is as mentioned above, just use some JB weld or the likes to seal them back up - no need to take the engine out, just mix the JB weld so its a little stiffer than normal and put on the dowel points, can be a tad tricky as they are deep into the casting, but doable - be sure they are really clean and free from oil/grease etc Never knew that. I've often wondered what the hols were. Every days a school day. |
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Post by stirling11 on Nov 17, 2021 11:18:36 GMT 1
the leak will be coming from the dowels, these are holes used during the casting process, they are then blanked off using dowels, originally they are sealed in place, but over time and with vapour blasting the sealant can be degraded, so they start to weep as mentioned above, the best course of action is as mentioned above, just use some JB weld or the likes to seal them back up - no need to take the engine out, just mix the JB weld so its a little stiffer than normal and put on the dowel points, can be a tad tricky as they are deep into the casting, but doable - be sure they are really clean and free from oil/grease etc Hey Dave I think I may have the same issue, an oil leak I can’t trace Are you able to circle one of the pictures of where these “dowels” are located, I’m unsure of where they are, either that or I’m just plain dumb cheers |
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Post by muttsnuts on Nov 17, 2021 11:27:47 GMT 1
the leak will be coming from the dowels, these are holes used during the casting process, they are then blanked off using dowels, originally they are sealed in place, but over time and with vapour blasting the sealant can be degraded, so they start to weep as mentioned above, the best course of action is as mentioned above, just use some JB weld or the likes to seal them back up - no need to take the engine out, just mix the JB weld so its a little stiffer than normal and put on the dowel points, can be a tad tricky as they are deep into the casting, but doable - be sure they are really clean and free from oil/grease etc Hey Dave I think I may have the same issue, an oil leak I can’t trace Are you able to circle one of the pictures of where these “dowels” are located, I’m unsure of where they are, either that or I’m just plain dumb cheers underneath the engine where the crank is located, you'll need the bike high up, or lay on your back, they are located at each end of where the crank bearings seat, they are deep in the casting recesses, hard to see if there is a load of muck on the engine. The picture do show the location very well, its the small round holes in the castings that are sucken in, they go right through the casting and are plugged with dowels |
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Post by philmill on Nov 17, 2021 22:55:28 GMT 1
I think the guys have explained this Phil Cases not as good as Mark's but another view to consider John Thanks John, thats definitely where the leak is, hopefully it is an easy fix, the bike keeps fighting me.... Phil |
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Post by stirling11 on Nov 22, 2021 4:35:17 GMT 1
Hey Dave I think I may have the same issue, an oil leak I can’t trace Are you able to circle one of the pictures of where these “dowels” are located, I’m unsure of where they are, either that or I’m just plain dumb cheers underneath the engine where the crank is located, you'll need the bike high up, or lay on your back, they are located at each end of where the crank bearings seat, they are deep in the casting recesses, hard to see if there is a load of muck on the engine. The picture do show the location very well, its the small round holes in the castings that are sucken in, they go right through the casting and are plugged with dowels Hi Dave Much appreciated I’ll have a look not much oil leaks however it’s a concern |
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Post by JonW on Nov 22, 2021 5:08:53 GMT 1
If these are dowels like the plugs on the ends of the selector shafts, cant you just give them a tap from the outside to knock them back into place and seal better?
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Post by midlifecrisisrd on Nov 22, 2021 9:38:04 GMT 1
I think rather than plugs they are filled after machining
Steve
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