RD Pistons and Rings

[BrianC]

My RD restoration is under way, with parts are being sourced in large(ish) chunks. I haven’t stripped the engine yet as I’ll do the chassis and body stuff first but I’ll get seals, Orings and gaskets coz I know I need them. Not sure what I will find piston wise, but piston ring availability seems to be a bit light on. I haven’t actively tried to source yet, just looking to see how much money I have to part with. I am hoping it is standard, bit of a hone and new rings, I don’t really want to go for a big bore kit. Can anybody point me in the right direction to source rings please? Is it just through David Silver etc? Are the 1100F ones used? Is there something special with R rings? (Apart from being ‘R’ rings!!). Thanks.

[GrahamR]

Hi Brian, I’m far from an expert on R’s but I believe OEM rings are no longer available. I seem to remember reading Andre’s article about his engine rebuild and he had the pistons machined to accept after market rings.
I am sure Andre has the answer somewhere in a previous article.

Graham.

[Anonymous]

HI Brian,

Honda NOS rings are hard to find these days but they do turn up. David Silver and CMS in Holland are two potential suppliers whenever they turn any up. Check their website regularly.

There are quite a few other options it seems as there’s been much discussion over recent years on various forums.

Recently Ralf Buhl in Germany advised that full barrel piston and Ring sets were available from Germany through Gerhard Mossner from TeamDor http://www.teamdor.com/
Not sure if you can just get the rings and if they are compatible with the standard pistons though.

1100F compression rings are different that the “R” rings. Slightly thicker by 0.2mm which means a bit more friction = slightly less power = last longer. You would have to modify the piston groove to use these.

Wiseco rings are compatible with the original pistons to a point. Both compression rings are identical to the R ones, but the oil control ring is not. I believe Gary Wise has used these in the past. You use the actual scraper rings but use the existing Honda, expander between the rings. The Wiseco expander is quite different and would require modification of the piston to increase the groove to accomodate it. Again I think Andre has done this with some of his engine rebuilds.

The Wiseco part number I believe is 2795XC available in both 70mm & 71mm.
.
I’m sure Andre and Gary can add to this info.

Steve

[Anonymous]

Hi All,
It’s along time since I did that article for the mag.
But I did use Kawasaki 71mm rings and they are identical (Japanese make) Top/Middle rings are fine except the oil control
spring which is wider. So as my springs were fine I refitted the springs and then fitted the new oil control
rings. If you wanted to use the new springs you would have to machine the piston oil groove out.
My engine had already been bored out by 1mm but I’m sure you will be able to get the std 70mm rings
if you look around. The wisco kit is 72mm and you also have to use their head gasket.
It must have been 5-6 years ago I did the work and the oil consumption is still very good.
Hope this helps. Cheers Gary.
PS one firm that helped me big time with my cb250k rings was Steve at piston/broke

[BrianC]

Thanks. I had thought there must be other 71mm bores around and had looked at a few Kwaka models. There wasn’t the detail on ring widths etc. Looks like I won’t have too much drama. It will be a few months before I get to the engine.

[Trevor Hughes]

Brian

I’ve found a company in Germany who appear to have 71mm Piston rings for the CB1100R/F advertised on their web-site. I don’t read German so its difficult to read but may a German member could help translate.

http://www.scheuerlein-werkzeuge.de/product_info.php?info=p688_honda-cb1100r-kolbenringe—1–uebermass.html

Regards

Trev

[Trevor Hughes]

It appears Cosworth make 1100R pistons.

[BrianC]

Thanks all. I purchased MG5 rings (Pretty sure, have to check the invoice and box) and they fitted fine. All gaps and clearances checked OK. Now I am assuming the pistons were still the originals. Bore was standard and it didn’t look like the engine had been changed at all.

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