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CB550/4K engine strip, Bore scratch
Gary400/4:
Hello all, I have recently acquired a CB550/4 K project bike to sort out, I have owned these previously and enjoy them more than the CB400/4.
I have stripped the engine to check it over, the engine was literally seized together, it took a lot of effort to remove the cylinder head, the cylinder barrel had accumulation deposits around the front barrel studs. I ended up with a few chipped fins. On inspection of the cylinder bores, the piston ring end gaps were still in service, but not by a lot, so I have purchased a new set of standard rings. On inspection of one of the bores, I note that a scratch is evident about 1cm long by 1mm deep running horizontal in the cylinder wall. I will be honing the bores to help the new rings to bed in. But I am worried about a ring getting snagged on the scratch as it motions up and down at revs. Is this something to be alarmed about?
taysidedragon:
It's difficult to judge without seeing it, but if the scratch is as deep as you say I would be looking at a rebore.
Even then it might be too deep and new barrels or liners may be required.
Laverda Dave:
+1 with Gareth's response. 1mm is very deep and I doubt even a +1.00mm rebore will remove it. Considering you now also have chipped fins I would personally be looking for another barrel but only once I'd got the whole engine apart and inspected especially if it has been sitting seized up.
Johnwebley:
If the scratch is only 1cm long and 1mm wide it shouldn't be an issue,
OK, it's not perfect, but the rings are at least 2mm or 3mm wide,
So they shouldn't drop in,
On 2 strokes the ports are far bigger,
Sent from my SM-A546E using Tapatalk
Bryanj:
Do you mean 1mm deep or wide? Wide probably ok but depp not.
If deep its too deep for a max honda size rebore but cruzin do a 3mm oversize kit taking it to 605 ish cc but dont expect a cheap rebore as that is a minimum of 6 passes per bore plus hone!
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