Wet Sump During Top End Rebuild /Cylender Hone Question

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Mar 1, 2007
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Hey guys. Another question. I am repairing the top end on my friends 1974 850 Commando. Once I removed the cylenders there was a LOT of oil in the crankcase. Do I need to remove some of it before I put the top end back on and start it up. I believe this is called wet-sumping and how do I correct it??? Is there the possibility of any engine damage?? I also checked the cylender bore and it is great. How much honing is reguired before a refit with Hastings rings?? How long do I keep the rock hone spinning to remove the glaze--3 or 4 seconds?? Or longer?? Can I damage the cyls by honing too much?? Thanks again for all the help you have given---Mark C.
 

L.A.B.

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Mark Cigainero said:
Once I removed the cylenders there was a LOT of oil in the crankcase. Do I need to remove some of it before I put the top end back on and start it up.

Yes it is generally a good idea to remove the excess sump oil and transfer it back to the oil tank (or replace with new oil).


Mark Cigainero said:
I believe this is called wet-sumping and how do I correct it???
Originally (when these motorcycles were ridden more regularly) this was less of a problem, but here is some info: http://www.norvilmotorcycle.co.uk/techtalk18.htm
It is possible to fit an anti-wetsumping valve, but there can be a certain amount of risk involved: http://www.nortonownersclub.org/technic ... etail.html
There have been a few discussions here about this in the past and doing a search is likely to find some of these.

Mark Cigainero said:
Is there the possibility of any engine damage??

Having already occurred?

Or likely to occur because of the excess oil (if that is what you meant)?

No, not really, unless the sump was excessively full of oil (more oil than the oil tank capacity) although starting up with a sump full of oil could blow the drive side crank seal out of position.
 
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cylinder prep

Hi Mark,
You said you were using Hastings rings. If you go to www.hastingsmfg.com they have a service column that is very informative. Under cylinder deglazing they state that a cylinder can be properly deglazed in 35-45 seconds. Of course, you will want to use the appropriate stroke speed (depends on how fast your drill is turning) in order to establish a 45 degree crosshatch pattern in the cylinder. They also emphasize the importance of thoroughly cleaning the cylinder afterward.
GB
 
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I have seen a lot of machine shops honing way too fine for cast iron rings. This part of the tech info from the hastings site is important.
"The finish produced by a 220-280 grit stone is most desirable. The cross hatch pattern should intersect at approximately a 450 angle. Too flat an angle leads to ring spinning which prevents seating the rings.

Probably the most critical part of the deglazing operation is the proper cleaning after deglazing. The residue of honing, if left in the engine, will rapidly destroy all moving parts. It is recommended that engines be cleaned thoroughly with soap and water. Clean with soap and water until the bore can be wiped with a clean white cloth without soiling the cloth. After clean up, oil the area to prevent rust formation. Waterless hand soap also serves as an excellent cleaning agent. "
Also don't oil the rings for the build just a few drops on the piston skirts do the trick.
 
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