Hi all. Newby here from Kiwi land. I have an 85 RD350 F which I find upon inspection, has both expander rings broken into 3 or 4 bits. The bits were still intact in the lower scraper ring grooves (thank goodness) but I have to ask, are they needed? The piston and rings are sweet, so I don't need to replace, and I don't want to have to order 2 complete ring sets, just to get 2 x expander rings. I'm thinking I can leave them out. Any thoughts?

erm... no!!

they are there for a specific reason and I would replace all the rings anyway if those have broken. the rings may have turned in the barrel making the ring expand into the ports causing a fracture, so make sure you have the piston pegs in place when reassembling.

drewps

^ if you dont put new scraper rings in, the piston will 'judder' during its reciprocations. I would think the other rings would wear much quicker. Why not replace all the rings while you are in there and give it a light hone.

Thanks guys. I think you are right. While i'm in there replace the complete ring set. Ive since found out you can't just buy the expander rings anyway. Thanks for the logic. Happy biking.