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350TSS · 10-12-2019, 09:27 PM

I was only able to steal about 4 hours in the garage today, it was definitely a learning experience.
First, I ground in both valves (vertical cylinder head) with fine grinding paste. I managed to get a nice fine grey continuous ring on both the seat and the valve head less than 1mm wide, all pock marks eliminated. Then, I reduced the valve head diameter to not more than 0.35mm above the outside diameter of the light grey ring formed during the valve grinding. This probably reduced the valve head outside diameter by about 0.5mm and thus effectively increases the size of the port by reducing the restriction caused by the size of the valve head. It works across the entire rev range. Maybe only a single brake horse power or two but worth doing nevertheless as it costs nothing and is simply about efficiency of an existing design. This took about 45 minutes with lots of care taken to remove any valve grinding paste and carbon detritus from the de-coke from anything and everything that was going inside the engine. (3 applications of brake cleaner and about 10 minutes wiping everything down with paper towels)
The next job was to fit new oil control seals to the top of the valve guides. I compared the old fitted ones with the new ones supplied by Moto Rapido (and a set included in a gasket set supplied by Athena).
The old ones were definitely “latched” onto a groove at the base of the protruding valve guide in the cam box above the combustion chamber. All the new ones were about 0.025mm smaller in diameter where the groove was supposed to fit. The space for fitting these valve seals is extremely limited as the valve closing fork limits(read precludes) access to the inner side of the valve stem.
First, I tried to get the seal to seat with the valve not in situ, but when I did get it to seat (I think) and I pushed the valve into the guide it simply removed the stem seal. - Bugger!!!

10-12-2019, 09:27 PM	#1045
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,419	I was only able to steal about 4 hours in the garage today, it was definitely a learning experience. First, I ground in both valves (vertical cylinder head) with fine grinding paste. I managed to get a nice fine grey continuous ring on both the seat and the valve head less than 1mm wide, all pock marks eliminated. Then, I reduced the valve head diameter to not more than 0.35mm above the outside diameter of the light grey ring formed during the valve grinding. This probably reduced the valve head outside diameter by about 0.5mm and thus effectively increases the size of the port by reducing the restriction caused by the size of the valve head. It works across the entire rev range. Maybe only a single brake horse power or two but worth doing nevertheless as it costs nothing and is simply about efficiency of an existing design. This took about 45 minutes with lots of care taken to remove any valve grinding paste and carbon detritus from the de-coke from anything and everything that was going inside the engine. (3 applications of brake cleaner and about 10 minutes wiping everything down with paper towels) The next job was to fit new oil control seals to the top of the valve guides. I compared the old fitted ones with the new ones supplied by Moto Rapido (and a set included in a gasket set supplied by Athena). The old ones were definitely “latched” onto a groove at the base of the protruding valve guide in the cam box above the combustion chamber. All the new ones were about 0.025mm smaller in diameter where the groove was supposed to fit. The space for fitting these valve seals is extremely limited as the valve closing fork limits(read precludes) access to the inner side of the valve stem. First, I tried to get the seal to seat with the valve not in situ, but when I did get it to seat (I think) and I pushed the valve into the guide it simply removed the stem seal. - Bugger!!!