Steering Head Bearing conversion to Tapered Bearing on a 1971 Honda CB750

For those who are planning to upgrade to tapered bearing, or are sooner or later forced to do it because of that "notch" (like myself) I have sort of illustrated the steps to a successful conversion using the bearing set part number 22-1011 which is distributed by Parts Canada and others in the US, I am sure. I bought mine at the local Honda dealer for C$ 39.95 (SKU 399014, OEM 22-1011). For those of you who might be offended by the technically incorrect description: the correct name is Single Row Tapered Roller Bearing but to keep it simple I will refer to it as tapered bearing.

• first thing I did was to remove the old ball bearing. I used a steel rod to push both races out the headstock, just more or less gently tapped in circles until they fell out. Somebody helped me out with removing the lower bearing races from the stem, he had a machine to do it. I recommend you go to some garage and have it done for a couple of bucks. Everything else was actually straight forward on my bike as nobody obvioulsy tampered with the bike in 33 years, the balls were covered in something that might have been grease decades before, I had a really bad notch. I found out later that this was due to too tight adjustment, but I had 19 nice impacts (pits) in all races anyway, so it was time to replace
• second step was to actually measure the whole system up to see if I should or should not assemble the 4mm thick spacer below the bottom bearing (as the original bearing had one integrated to accommodate the seal) which was included. I decided to install it. It seemed as if the whole stem would move up a couple of mm (no ore than 3mm), the inner dimensions seemed ok. I did not spend a lot of time on it, which I found out later, could have been disastrous (but wasn't).

• Next thing was to install the lower bearing on the stem. The stem went into the freezer, the bearing in the oven at 50°C. Positioned the 4mm washer, the seal and the bearing on the stem, the old lower inner race on top of that, I had a 1 1/4 copper pipe left over which I used to wack the bearing down in small steps, adjusted the seal before the final wack and ... done. Nice one.

• next step was to install the two races, both went in the freezer, both the original ball bearing ones were reduced in diameter (I used a file) and later used to push both races in. That went pretty easy, the cold (shrunk) races went in with only little force. You see the white colouring on the race? Ice.

• next step was assembly: all went well, I have illustrated the steps, enough thread visible and usable (with the 4mm spacer installed at the bottom).

• At this step I realized somethong was wrong, not badly wrong just odd wrong: there was a 3-4mm gap between the the headlight ears and the upper triple tree! So the whole assembly although of the same internal length went up within the headstock about 3-4mm due to the dimensional differences between ball bearing and tapered bearing. I did not pick that up during my initial measurements.

• I have to correct myself after dealing with tapered bearings on a BMW (same question - spacer or not): the reason for the 4mm gap is not the dimensional differences as initially thought, it is actually the 4mm washer I used on the lower triple tree. If I hadn't used the washer, the lower triple tree would have been raised by 4mm closing the gap, so no need for a fix.
  Never mind, not to worry, two 1 1/2in washer from the plumbing department at Canadian Tire fixed it (they had no black ones!). I might reduce that to one at a later stage, after everything has settled and eased.