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350TSS · 08-03-2018, 05:53 PM

Spent today working on the fork yokes/steering head bearings. I want the finished yokes to be polished alloy because all the best café racers always have polished alloy. At one time I considered buying a machined billet top yoke but that money has been spent on wheels so I will retain the M900 top and bottom yokes, trouble is they are not things of beauty, rough cast with quite marked casting lines and various holes and lugs in them. I am stuck with them also because I have designed the instrument and the headlamp attachment systems around use of these threaded holes.
The top yoke took about 3 hours to get looking reasonable, process was 10 minutes in the blast cabinet to get rid of the surface crud, then 10 minutes on an 80 grit drum sander to remove the worst of the casting lines, then about half an hour with a block and 120 grit sand paper then, 240, 400, 800 and 1000 wet and dry. It really needs 20 minutes on a polishing mop on my bench grinder to get a really good shine and one is on order.
The bottom yoke was more problematic as the bearing would not release from the stem. Years ago, I bought a Machine Mart bearing puller for just such a job, unfortunately the steering stops prevent the jaws sitting flush with the top of the bottom yoke, even if they were able to engage I suspect that the infinitesmal gap between the stem and the inner race means that the MM puller is more ornament than use.
I tried chisels of various persuasions and eventually resorted to a small grindstone in a drill held in a vice. However hard you try, it is virtually impossible not to cut into the stem as you grind through the inner track. Fortunately I got away with a 0.5 mm deep notch on the stem about 4mm long. I then repeated the sanding /polishing process on the bottom yoke.
Postman came today with a CF front mudguard from a 916 that I got off fleabay for £90,the quality is not the best I have seen.
I have given up on making my own front mudguard as it is will be a complicated mold and I would rather spend the time working on the rest of the bike. Also Simply Bearings delivered a new clutch casing seal.

08-03-2018, 05:53 PM	#604
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,419	Spent today working on the fork yokes/steering head bearings. I want the finished yokes to be polished alloy because all the best café racers always have polished alloy. At one time I considered buying a machined billet top yoke but that money has been spent on wheels so I will retain the M900 top and bottom yokes, trouble is they are not things of beauty, rough cast with quite marked casting lines and various holes and lugs in them. I am stuck with them also because I have designed the instrument and the headlamp attachment systems around use of these threaded holes. The top yoke took about 3 hours to get looking reasonable, process was 10 minutes in the blast cabinet to get rid of the surface crud, then 10 minutes on an 80 grit drum sander to remove the worst of the casting lines, then about half an hour with a block and 120 grit sand paper then, 240, 400, 800 and 1000 wet and dry. It really needs 20 minutes on a polishing mop on my bench grinder to get a really good shine and one is on order. The bottom yoke was more problematic as the bearing would not release from the stem. Years ago, I bought a Machine Mart bearing puller for just such a job, unfortunately the steering stops prevent the jaws sitting flush with the top of the bottom yoke, even if they were able to engage I suspect that the infinitesmal gap between the stem and the inner race means that the MM puller is more ornament than use. I tried chisels of various persuasions and eventually resorted to a small grindstone in a drill held in a vice. However hard you try, it is virtually impossible not to cut into the stem as you grind through the inner track. Fortunately I got away with a 0.5 mm deep notch on the stem about 4mm long. I then repeated the sanding /polishing process on the bottom yoke. Postman came today with a CF front mudguard from a 916 that I got off fleabay for £90,the quality is not the best I have seen. I have given up on making my own front mudguard as it is will be a complicated mold and I would rather spend the time working on the rest of the bike. Also Simply Bearings delivered a new clutch casing seal.