restoration - pistons -parts
Posted: Fri 10. Dec 2004, 22:02
I need help getting parts, especially pistons for a 65 R50/2.. any ideas. I'm restoring her and am now stuck.
All the parts you need are in the Online Shop at this site. You do not say why you are buying new pistons. It would be unusual if you were buying standard size pistons.
If the cylinders are not worn past tolerance and not scored, normally you could merely hone the cylinders and then reinstall the old pistons with new rings gapped to fit the cylinders.
If the pistons need replacement because they are worn or damaged, then the cylinders are also likely to be worn or damaged. In this case you would want to bore the cylinders to next oversize and use next oversize pistons.
Keep in mind that cylinders must be bored to fit pistons - for an R50/2 the cylinders should be 0.05 mm bigger than the pistons for solo bikes. While pistons are marked on top with their nominal diameter to tell which oversize they are, this may not be the exact actual diameter due to manufacturing variations.
After deciding to go oversize, the safest procedure is to order the pistons first, then verify the measurement and bore the cylinders accordingly. Or, just give the pistons to the machine shop and tell them to bore the cylinders 0.05 mm larger.