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1986 Honda Xr250r engine rebuild

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This is the first time on this forum and I would like to say hello. I just picked up a 1986 XR250r. The previous owner said it needed a top end rebuild. It blew constant smoke and had crankcase pressurization causing oil being pushed from the breather. This tells me bad rings or piston.  I took the engine apart and have a few questions. It has a Wiseco .020 piston 73.5mm and rings. The bore and piston do not have a scuff on them. The internals of the engine are spotless . No sludge or varnish. The bottom end is tight.  I contacted Wiseco and I measured the ring diameter and they were about .4mm undersize indicating wear. The cam chain also has some slap. I am pricing  parts on ebay they have complete gasket sets by NE for about$40. New cam chains for the same. Are they junk parts or ok? The rings will be Wiseco. I will probably put new valve seals in also.  Any input or suggestions here? It has been a long time since I messed around with small engines. Thanks

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I would say, if you can source it, use only an OEM cam chain. Same with valve seals. If not available, hopefully someone previously in your position here can recommend reputable aftermarket parts.

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The cam chain I purchased is a Pro x made in Japan. I spoke with a Wiseco tech(same company). He said they are great. What about this gasket set http://www.ebay.com/itm/Honda-Full-Complete-Engine-Gasket-Full-Kit-Set-XR-250-R-XR-250-L-1985-2006-/201608513376?fits=Year%3A1986|Make%3AHonda|Model%3AXR250R. Are these good to go? I will not be racing this bike. Just casual trail use.

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