Topic: Crankcase pan sludge.

[oldhondafan]

Quick question...in relation to CB350/450 twins...but relevant to SOHC4s I should think (and I have one). 

Anyway, for old bikes even well kept sludge and crud collects at the bottom of the crankcase.  I have a 350 twin that has sat for a long time.  I revived it, cleaned the oil filter and clutch etc, put in fresh oil, ran it 50 miles, drained the oil, recleaned clutch and oil filter, and filled it with fresh oil again.  It runs great, tons of compression, no untoward engine noises.  But after 550 more miles I did an end of season oil change and was surprised to find some very fine metal flecks (slightly gritty to the touch) in the sump of the oild drain plug, and in the oil filter where there was also some sludge/crud.

My Q....is it likely that this stuff is actually old sediments from the crankcase pan being mobilized again by the circulating oil?

I have a hard time imagining its engine wear during my short time (600 miles) with the bike (total miles on the bike is 16500).

Thanks gentlemen. 

[Raul CB750K1]

I'm restoring a CB350 twin and this subject was deal with in the past. Do a search and you will find lots of pictures -look in the "other bikes" forum. That metal shavings are very likely due to the camchain running loose inside the tunner and filing the aluminium walls. Tighten it and you will be good to go.

When I opened the cranckases there was a lot of sludge at the bottom, and even with a high pressure hose it was hard to remove. There is some kind of labyrinth for the oil to drain so the speed is very slow and there are no chances of it to ever go away by itself, but it's no big problem.


Raul

[Raul CB750K1]

Check this out:

http://www.sohc4.us/forums/index.php?topic=5626.0

http://www.sohc4.us/forums/index.php?topic=10505.0

http://www.sohc4.us/forums/index.php?topic=5213.0



Raul