Topic: cb400f top two rings

[oldfart]

I need a favor.  I know the oil ring was modernized when the 350 four became the 400.  But were the top two rings (compression and scraper) also modernized or are they the same 1.5mm thickness as the 350?  I will be very grateful for information.  Thank you!

[welshman]

I just put rings on my 400 last weekend.I couldn't measure or see any difference between the two.However the ring I used as the scraper wouldn't turn very well in the ring groove.Switching them over fixed the issue.FWIW the top ring was a kind of carbon or black colour. The scraper was shiny silver.These were aftermarket rings

[oldfart]

Thanks Welshman.  I need to know if the thickness of the two top rings (compression and scraper) for the 350 is the same on the 400.  I suspect not since the 400 oil ring was modernized and likely the modernization included putting thinner compression and scraper rings.  That is what I am after.