How many piston ring?

[Newtoit]

Hi fella's I've just bought a 447 XS650 B from the US ( I'm in the UK) and I'm in the process of stripping it down due to lack of compression. The Pistons have 3 grooves but only 2 rings fitted (solid middle and bottom sandwich style oil ring). My Haynes manual shows 3 rings but the replacement ring set I've just purchased (447-11610-00) comes with 2 rings, which is correct? Thanks for the help.

 

[motormike]

.. every 447 I'm ring'd..two upper rings.. one slightly thicker then the other I recall... and the 3 piece oil scraper set... we just got a set off ebay..

 

[littlebill31]

Well, you need more than 2.
3 rings...top...middle...oiler set (oiler is actually 3 rings as a set)
Did you get your bore measured and the pistons checked?
If they are out of spec, you will need to hone (should be done anyway imho) and possible go oversized.

Here is Heidens website:
https://www.heidentuning.com/xs650-...piston-ring-set-80-mm-replacement-detail.html

 

[5twins]

I guess you know now why it had no compression, lol. I've seen some strange things around here but this is a first.

 

[gggGary]

Hi fella's I've just bought a 447 XS650 B from the US ( I'm in the UK) and I'm in the process of stripping it down due to lack of compression. The Pistons have 3 grooves but only 2 rings fitted (solid middle and bottom sandwich style oil ring). My Haynes manual shows 3 rings but the replacement ring set I've just purchased (447-11610-00) comes with 2 rings, which is correct? Thanks for the help.

When I did a search on that part # 447-11610-00 I came up with pictures showing three rings, as they should be. The cruzinimage rings are also 3 ring sets.
https://www.ebay.com/itm/YAMAHA-XS6...m20d788c139:m:mxX_XfLai4uTB-D7okyJLwQ&vxp=mtr

 

[Newtoit]

Thanks for the info fellas, guess I'm of to the shop to buy a set of rings with a top ring included. Many thanks again

 

[weaselbeak]

I guess you know now why it had no compression, lol. I've seen some strange things around here but this is a first.

I don't know for sure. I remember a Geo Metro that skipped one ring for fuel economy increases. My BIL bought one. Ran fine and never used oil. Don't some drag bikes go a ring short as well? Certainly 3 rings are going to be normally better than 2 all things considered, but I'm not sure it's a death sentence.