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[m1ks]

Could someone verify, (or otherwise) for me that the middle ring with a stamped dot has the dot uppermost, the oil control ring is obvious being stamped top and the book says 'circle' upwards so i'm working on the principle it means the dot and thats up.

Thanks

[Alan R]

Hi Matey---------- general convention in the absence of any instructions to the contrary is any markings face upwards. Make sure they are "Gapped" in the bore according to the dimensions given in the manual----also that they are free to move in the groove ( Very "60's" ). Don't forget the cylinder base gasket !! Be careful when lowering the barrel down not to trap the rings, eh ? Gaps at 120 degrees, lubricate freely--- a slight rotary, wobbly motion to the barrel helps the taper at the lower part of the cylinder "gather-up" the rings and compress them, one at a time. Place some cloth in the crankcase mouth just in case you do break a ring. Engage smug mode on completion.

[m1ks]

Thats good enough thanks.
Was not going to bother removing them but as I was cleaning the carbon and polishing the piston crown I thought i'll whip them off and check the grooves are clean and it meant I could tape around the top of the piston while I cleaned it.
Glad I took them off to check, whiles they're in good order it would appear that the middle and lower oil control ring were fitted upside down, the middle one has a little dot, forgivable, easy to miss, the oil control ring is stamped TOP, a good clue you'd think!
They were all lined up quite nicely too, not perfectly but near enough, which may well explain the recent loss of compression before stripping, (along with the slightly stuck open inlet valve due to the bit of thread swarf from the plug hole.
Gaps in the bore are fine, the whole thing is very clean inside as it happens and little carbon, i'm wondering now if someone has replaced the piston, rings and barrel sometime in it's 24,000 km of use, which would also explain the previous operatives love of black silicone sealer. and the reason for every mating surface overflowing with it.
Getting there, just lapping in the valves now.

[Les H]

Hi. I would deffinitely buy a new set off rings. Apart from the normal amount of wear on them, I doubt they would ever seal properly if you now put them back in the correct way up.

[m1ks]

I'll chance it for now, theres little obvious wear to the barrel, piston or rings, no evidence of oil blow by despite the wrong orientation and having just forked out for a pile of stuff between our host and ebay that I definitely need and more bills coming up shortly it would just have to wait anyway, in the meantime I might as well rebuild it with what I have and if it turns out to be low on compression or otherwise giving fault it'll only cost me the time to strip the new rings and another £5 for a top end gasket set.

[Alan R]

Hi Matey---------try this before re-assembly}----a)Fit the rings to the piston (in the correct way--of course!)--b) Make a dummy con-rod out of some 1/2" ply or similar.---c) Apply some liquid metal polish then try the assembly into the cylinder---move up & down several times. ----- d) Remove, wash and check for "Highlighting" marks. Ideally they will be evenly spread on the contact faces. Incidentally, recently and unbeknown to me ---I fitted the 2 compression rings UPSIDE DOWN on a re-bored Honda PC50. It smoked like a 2-stroke having a tantrum. EVENTUALLY--and after many a "jovial" episode--it dawned on me that the only remaining variable left had to be piston rings. Upon removal one had full-face contact but the other only had HALF the face rubbed-- as if tapered ( Possibly a crude form of ridge-dodger ??). A visiting friend eventually solved the mystery when he saw the markings on the rings-----and that was with a 10x magnifying glass. I re-fitted in the correct way and---------- BINGO !! NO SMOKE.

[m1ks]

The marking on the middle ring is like that, it's a tiny dot, it may even not be a direction marking, the wear is even across the thickness of the ring, not one side or the other and theres no obvious taper, the oil control ring is quite apparent in it's marking though as I said.
Head is back together re the valves etc, which are lapped in, I WAS fitting a stem seal to the inlet, however, with the bottom spring plate on it simply would not stay in place on the guide, I degreased it and tried drifting it on and it kept slipping back, to the point where it began to deform from numerous attempts, so that's now scrap and the head is reassembled without seals.

[Alan R]

Hi there-------- yes, my several attempts at fitting a seal on the inlet also failed--and that despite phoning HM and talking it through-----£15 down the drain...And on a pension as well !! I'm due to do some shopping in person soon so I'll be asking them to take ad hoc samples of seals and guides from their stores bin and just trying it for themselves. I think there is a discrepancy somewhere in the dimensions of either the seal AND/OR the guide. Like you I also re-built without any seals fitted-----I really wanted at least the inlet on for obvious reasons. It's probably better to leave the exhaust plain anyway to be sure of some lubrication in the hottest part of your engine. That head has just done 1,000 miles recently and there is a slight oil consumption --- estimate 1/8" on the dipstick per 200 miles of "Spirited" club riding on a 17t sprocket. I can live with that.(PS---COMMA 20/50 used)

[m1ks]

Hi Alan,
Glad to hear it's not just me then.
Likewise I was just fitting the one to the inlet leaving the exhaust without.
The biggest problem as I can tell, is that the top of the guide is smooth brass and has the inward taper, whenever i've done stem seal replacements theres always been a lip or ridge to ensure a snug and secure fit. Fitting without the bottom plate allows you to press on the seal quite well, (as I discovered then realised i'd not fitted the bottom spring plate, theres just not enough guide stem to press the seal onto and allow it to grip, even when i'd degreases the outer portion of the guide and inner lip of the seal it still wouldn't stay put, i'd drift it on and it'd just taunt me by gradually lifting and popping off like one of those popping toys you got from the 2p plastic egg machines as a kid. i'm not convinced it would have stayed anyway without the bottom plate as it popped off with worrying ease once I realised I had to fit the bottom plate first.
By the time i'd exhausted my methods of encouragement, i'd encouraged it out of round thereby making the use of it pretty pointless but i'd certainly say it needs reshaped guides to fit succesfully.
Annoying but it all adds to the fun and games, I guess it's managed 24000km without just fine so hopefully will manage more the same.