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350TSS · 06-01-2020, 01:40 PM

I had a frustrating 3 hours in the garage yesterday, the plan was to re-fit the vertical cylinder barrel and head and remove the horizontal one and clean/decoke piston.
First I inverted the vertical piston in a jar of acetone and then after about half an hours soaking cleaned out the ring grooves with a tooth brush. the rings stayed on the piston as I wanted to avoid the risk of breaking them getiing them off. It worked a treat and the rings are now completely free to move.
I bought new gudgeon pin circlips from Moto Rapido and after inserting the gudgeon pin tried to fit a replacement. The one I had removed pinged across the garage striking a few metallic objects ( so at least I know it is not in the bowels of the crankcase) on the way and will never be seen again. I had no intention of refitting the old circlip but I did not have a sample of the old one to compare with the new ones.
After a good hour of struggling and with the crankcase mouth stuffed full of paper towels I still had not manged to get the circlip to engage properly in its groove.
I find when something goes badly it is as well to walk away and do something else for a while then come back to it afresh.
So I moved onto removing the horizontal cylinder.
An hour and a half later the cylinder had risen about 6 mm from its face on the crankcase. Galvanic corrosion between the aluminium barrel and the cylinder head studs was the culprit.
After a lot of tuggung and jiggling and a block of wood and a hide mallet on the cylinder base it eventually came off.
To clean out the stud holes I cut a slot in the end of a length of 8mm aluminium bar and put a strip of emery paper in the slot and reamed the corrosion out of the stud holes with the battery drill.
I then managed to remove one of the circlips from the horizontal piston without it disappearing into the nether regions of the garage.
The fitted circlips and the supplied circlips are not the same at all.
The fitted ones have a 90 degree bend at one end that will engage nicely with the machined indent in the piston adjacent to the circlip groove. The supplied ones have no such bend and are approximately 1mm bigger in diameter than the old one. I think I have the wrong ones.
So all three hours achieved was removal of the front cylinder barrel and a few paint chips on the outside of the starter motor where I resorted to a screwdriver as a lever to remove the barrel.

06-01-2020, 01:40 PM	#1062
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	I had a frustrating 3 hours in the garage yesterday, the plan was to re-fit the vertical cylinder barrel and head and remove the horizontal one and clean/decoke piston. First I inverted the vertical piston in a jar of acetone and then after about half an hours soaking cleaned out the ring grooves with a tooth brush. the rings stayed on the piston as I wanted to avoid the risk of breaking them getiing them off. It worked a treat and the rings are now completely free to move. I bought new gudgeon pin circlips from Moto Rapido and after inserting the gudgeon pin tried to fit a replacement. The one I had removed pinged across the garage striking a few metallic objects ( so at least I know it is not in the bowels of the crankcase) on the way and will never be seen again. I had no intention of refitting the old circlip but I did not have a sample of the old one to compare with the new ones. After a good hour of struggling and with the crankcase mouth stuffed full of paper towels I still had not manged to get the circlip to engage properly in its groove. I find when something goes badly it is as well to walk away and do something else for a while then come back to it afresh. So I moved onto removing the horizontal cylinder. An hour and a half later the cylinder had risen about 6 mm from its face on the crankcase. Galvanic corrosion between the aluminium barrel and the cylinder head studs was the culprit. After a lot of tuggung and jiggling and a block of wood and a hide mallet on the cylinder base it eventually came off. To clean out the stud holes I cut a slot in the end of a length of 8mm aluminium bar and put a strip of emery paper in the slot and reamed the corrosion out of the stud holes with the battery drill. I then managed to remove one of the circlips from the horizontal piston without it disappearing into the nether regions of the garage. The fitted circlips and the supplied circlips are not the same at all. The fitted ones have a 90 degree bend at one end that will engage nicely with the machined indent in the piston adjacent to the circlip groove. The supplied ones have no such bend and are approximately 1mm bigger in diameter than the old one. I think I have the wrong ones. So all three hours achieved was removal of the front cylinder barrel and a few paint chips on the outside of the starter motor where I resorted to a screwdriver as a lever to remove the barrel.