Topic: 550 rebuild question

[78 Basketcase]

I have a 550 motor that was seized. I got it free and pulled the cylinders. As expected they are in rough shape and was hoping to have them bored out and replace the rings. I took the cylinders to a shop to be cleaned up. With a simple glance the shop owner said I would have to go up in piston size to rebuild this motor. I am no expert so I turn to you guys. What do you think? Also, has anyone purchased aftermarket piston kits from this buyer on eBay or know anything about them? http://cgi.ebay.com/ebaymotors/New-Set-four-Honda-CB550K-CB550F-Piston-Ring-Kit-50-/360356409805?pt=Motorcycles_Parts_Accessories&hash=item53e6ea71cd#ht_2871wt_948

I was hoping to have a running bike on a budget but it doesn't appear to be the case.

[bryanj]

You cannot under any circumstances just fit new rings after a bore----it has to be complete oversize piston kits, and if the bike was siezed with rust, yes it is probable it does need a re-bore anyway.

It may be chaper to get a used set of cylinders complete with pistons on ebay and run those, rather than the new kits plus rebore----either way you need a top end gasket set at least.

[78 Basketcase]

Thanks for the feedback. After a lot more reading last night I came to the same realization. Guess I'll be shelling out more cash. Oh well... I rather have it done correctly.

[fletcha221]

Keep in mind....shops are in the business of boring  and honing cylinders. Measure the pistons and cylinders, if they fall within spec, and the cyl walls are not scored, I would suggest stock rings. My 750 motor was stuck, but i was able to get it free and rebuilt it with new gaskets and rings. Perfect compression on all Cyls. All in, I've spent 150 dollars for rings and gaskets.

Do you have any pictures of the cyls/ pistons?