Compression gone on 1 cylinder :(

[CROFTY1984]

Hello all.
My A65 dumped all it's fuel into the bottom end (again). Thankfully I didn't ride it.
I've put new carbs on, rather than bugger about with the old ones. Knowing the fuel will have washed the bores, I put a bit of oil into the cylinders. I turned over the engine with the kickstart, plugs out. I turned it over with plugs in, to "squish" the oil down the bores a bit. I put a bit of pressure on the kickstart, but it's not like I jumped up and down on it, not wanting to do any hydraulicing-type damage. Plugs out, turn past compression, plugs back in.
I blew out the cylinders and now the RH cylinder kicks over as you'd expect, but the LH is terrible, you can turn the kickstart with your hand.

I don't know what to do. I've not started it (no spark but that's not a concern right now). I'm tempted to try and fire it up as a single on the RH cylinder, if anything's stuck maybe it will jar it loose. But what could I have done?
I hope I wouldn't have bent a con-rod with just my weight on it.

I'm at a real loss. I thought I was getting close with this bike, but nearly 2 years on and it's another slap in the face.

[Mike Farmer]

 

Bad luck there sir.

Probably easiest first check---stuck valve (sounds most likely to me--so hope)
Second---head gasket ---pour some oil into the head/cylinder joint area, kick it over and have someone check for bubbles---not foolproof but may give an indication.

A bent rod would still compress. so I think very unlikely

After that it sounds like spanner time again. Broken ring etc

Mike

[A10 JWO]

Would not try to start it sorry mate, spanners indeed. Good time of year for engine restorations. If you need any bits try Kidderminster M/C's.

[CROFTY1984]

Oddly it seemed to cure itself mostly, so assuming stuck valve. I was turning the bike over with the RH plug out and it got (mostly) back. I think it's still not 100% though. Have it running now.
I have a feeling the exhaust valve isn't perfectly closing. This might sound odd, but the LH exhaust tone has more of a sharp "crack" noise coming out of it, whereas the RH is a bit duller sounding. It's always seemed to be a bit louder on the left when I've ridden it in the past. Going to sort all my valve clearances and see if that helps.

Thanks for the advice all. I'm pleased today, it took the wind out of my sails a bit yesterday.

[A10 JWO]

I am pleased, but keep us updated. Don't go too far from home and watch for smoke in your mirrors.