HS50 Rings

[copyman]

Hi,

I went to buy HS50 standard rings at the usual places , Jacks & PartsTree and showed no longer available, only the oversized were available. Ended up buying a standard set on Ebay and when I received them they are much thinner and oil expander is different (see pic). Jacks & PT did show something about superseded to new part #. Tried looking that # up and showed a piston / ring set. This is first time I'm rebuilding HS50 and it's very confusing compared to the HS40. Not many rings available. Only thing I can think of is these thinner rings are used with superseded piston?
Thanks for the help

 

[cfh]

There's two sizes of HS50 rings. Mid-1990s then changed to a slightly smaller diameter piston and the rings decreased in thickness. As for the oil ring, there are a couple different makers of rings. Some use the coil expander and some use the ring expander. They both work fine. But you have to use the correct thickness ring. If you post your engine number/letter that would help a lot. For example, HS50 models "G" and earlier and HSSK50 models "L" and "M" use the thick rings (2 13/16" bore 198cc). Later HS50/HSSK50 engines (2 51/64" bore 195cc) use thin piston rings (HS50 models "H" and later and HSSK50 models "N" and later.)

HS50 piston rings (thick): #33567 (std)
HS50 piston rings (thick): #33568 (.010 over)
HS50 piston rings (thick): #33569 (.020 over)

HS50 piston rings (thin): #40006 (std replaces #36076)
HS50 piston rings (thin): #40007 (.010 over, replaces #36077)
HS50 piston rings (thin): #36078 (.020 over)

Note things on ebay are often not correctly listed. It may be because the seller things all HS50 std rings are the same, which clearly they are not. I hope this is helpful.

 

[copyman]

Hi, Thanks for that detailed info. Using your # 33567 I was able to find a set, can't believe they were $50, ouch! That's what I paid for the whole engine

Sorry should of posted Model #: HS50 67207D, Serial 3187B. Stamped on top of blower housing not on side plate. Black engine with black plastic gas tank. Starter rewind riveted on. Think it's 1973 or 1983 engine if reading serial # correctly? I always get confused when trying to figure the year

Thanks again

 

[cfh]

that would be 1983 as it's a "D" variant. That means thick rings, big exhaust value. Probably still points/condenser (not cdi.)

 

[copyman]

Thanks for letting me know the date. Yes, Points / Cond engine.