Compare your pistons with these.I removed the rocker cover, head and cylinders and didn't find any thing damaged or worn severely to indicate the loud rattle it was making other than the score marks on each side of the back of the pistons and the rear of the cylinders??.the front cam chain guide looks untouched after 4000klm. Only thing so far is a piece of high tensile wire/clip i found in the bottom of the clutch case. It almost looks like a gudgeon pin clip torn in half??.View attachment 205830View attachment 205828View attachment 205829
You're lucky you found the piston/bore issue though. It isn't right as it is.You nailed it Bob, checked the clutch basket and sure enough there's a broken spring. Might be why I couldn't find the rattle with the stethoscope but the wire/ clip type parts I have found are 2mm diameter and the clutch basket springs are 4mm diameter plus there is the piece of thread and the chunk of alloy that I can't explain.
Am I up for new rods ?
Yes, that looks like what happened, it was too tight in there.
I have ordered new con rods, big end bearings and crank pins plus all the seals for the shafts in the transmission. I will get the crankshaft rebuilt and balanced and the cylinders honed and fit new .025 over pistons and rings , bead blast the head and fit new valve stem seals . Thoughts on weather i should replace the cam chain and front guide?Those small ends are worn out, it's not 9 o clock it's the whole top and bottom that's gone the 9 o clock part still has some of the original copper coating on it,
Since you're doing all that, I would.I have ordered new con rods, big end bearings and crank pins plus all the seals for the shafts in the transmission. I will get the crankshaft rebuilt and balanced and the cylinders honed and fit new .025 over pistons and rings , bead blast the head and fit new valve stem seals . Thoughts on weather i should replace the cam chain and front guide?
Replace.Thoughts on weather i should replace the cam chain and front guide?
I had a local machine shop check the cylinders and pistons as there were no markings on the pistons and they match ok. They say the score marks are from running without oil, which would have happened when one of the oil delivery bolts on top of the rocker cover came out and it pumped all the oil out while I was on the motorway and couldn't stop for a kilometre or so. Probably done 3000 klms since then and it seemed fine until the recent rattle started.i did talk to Geoff at geoffs xs and he offered to hone the cylinders but the damage is all on me and postage isn't cheap.Shame you have to redo all this work.............Did you contact the supplier?
I had a local machine shop check the cylinders and pistons as there were no markings on the pistons and they match ok. They say the score marks are from running without oil, which would have happened when one of the oil delivery bolts on top of the rocker cover came out and it pumped all the oil out while I was on the motorway and couldn't stop for a kilometre or so. Probably done 3000 klms since then and it seemed fine until the recent rattle started.i did talk to Geoff at geoffs xs and he offered to hone the cylinders but the damage is all on me and postage isn't cheap.