Engine rear oil drain hole cleaning

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Saber

Saber

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Im getting ready to put cylinders and head back on. Before I do that, I am thinking it would be a good idea to make sure the little rear oil drain is cleaned out in the crankcase. I don't have any indication of a blockage. Just some ocd and peace of mind therapy. I'd like to know the general routing of that hole in the crankcase and where it ends. The timing side was not disassembled. So i am a little leary of blowing or pushing any gunk somewhere that i cant access if thats where it goes. Any tips for cleaning that out are welcome.
 
Here
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You will have to take the timing cover off
 
If you've been following my drama over on the Misfire Troubleshooting thread, at about page 6 or 7, we've settled on a poorly draining intake rocker compartment drainage down into timing chest as the likely cause of smoking exhaust, esp left side....and also tentatively pinning the original misfire issue on that as well. With the help of those on the thread, I learned where that drain is positioned in the rocker compartment (4 0'clock position looking forwards on bike, partially obscured by the valve spring seat). I was able to poke it with a wire down to at least the bottom of the cylinder block, where it would go no further (maybe a tight bend before exit to timing chest?). Go a very long spray can straw in there as well and hit it blasts of WD40. Well the smoking exhaust as cleared up and misfires seem to have gone (though still need to confirm with a carb swap to be conclusive).
 
As the oil drain hole is partially obscured by the valve spring cup
And I'm a bit OCD
I opened the the drain hole slightly and formed a small gulley with a Dremel to aid the oil running away
If the head has been off for any reason on my bike I always remove the timing cover and blow back the other way with an air line to check it's clear
It takes very little time,let nothing get past you
And you don't have to wonder/worry about it
 
Tornado said:
If you've been following my drama over on the Misfire Troubleshooting thread, at about page 6 or 7, we've settled on a poorly draining intake rocker compartment drainage down into timing chest as the likely cause of smoking exhaust, esp left side....and also tentatively pinning the original misfire issue on that as well. With the help of those on the thread, I learned where that drain is positioned in the rocker compartment (4 0'clock position looking forwards on bike, partially obscured by the valve spring seat). I was able to poke it with a wire down to at least the bottom of the cylinder block, where it would go no further (maybe a tight bend before exit to timing chest?). Go a very long spray can straw in there as well and hit it blasts of WD40. Well the smoking exhaust as cleared up and misfires seem to have gone (though still need to confirm with a carb swap to be conclusive).
Click to expand...

It's a tight bend below the barrel surface in the timing case, easier to pull the timing cover and shoot a bit of compressed air in from there
 
Tornado said:
If you've been following my drama over on the Misfire Troubleshooting thread, at about page 6 or 7, we've settled on a poorly draining intake rocker compartment drainage down into timing chest as the likely cause of smoking exhaust, esp left side....and also tentatively pinning the original misfire issue on that as well. With the help of those on the thread, I learned where that drain is positioned in the rocker compartment (4 0'clock position looking forwards on bike, partially obscured by the valve spring seat). I was able to poke it with a wire down to at least the bottom of the cylinder block, where it would go no further (maybe a tight bend before exit to timing chest?). Go a very long spray can straw in there as well and hit it blasts of WD40. Well the smoking exhaust as cleared up and misfires seem to have gone (though still need to confirm with a carb swap to be conclusive).
Click to expand...
Yes, I have been watching your misfire thread with interest.
Tornado said:
If you've been following my drama over on the Misfire Troubleshooting thread, at about page 6 or 7, we've settled on a poorly draining intake rocker compartment drainage down into timing chest as the likely cause of smoking exhaust, esp left side....and also tentatively pinning the original misfire issue on that as well. With the help of those on the thread, I learned where that drain is positioned in the rocker compartment (4 0'clock position looking forwards on bike, partially obscured by the valve spring seat). I was able to poke it with a wire down to at least the bottom of the cylinder block, where it would go no further (maybe a tight bend before exit to timing chest?). Go a very long spray can straw in there as well and hit it blasts of WD40. Well the smoking exhaust as cleared up and misfires seem to have gone (though still need to confirm with a carb swap to be conclusive).
Click to expand...
Yes, I have been watching your misfire thread with interest. Its no coincidence that I started this thread after learning from yours....Thank you!
 
I was working on a set of cases I had acquired and was just going over all the oilways with a WD40 aerosol and found that drain hole blocked, the hole is small and has a 90 degree turn at the bottom, it was blocked just there. Externally there was no sign it was blocked.
 
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