This is a GS1200SS Yoshimura ST-1 cam installation. Somehow the pricing has reverted to what it was before.
When you swap out the cam, as the RPMs climb, the bike speed rises along with it—or so you might say. With the ST-1, the bottom end doesn’t thin out terribly, and it becomes really fun to ride.
Apparently it’s hardly ever used for street riding, so both the cam and rocker arms are in exceptionally clean condition.
The rocker arm area will be reused.
I’ll polish the journal and cam lobes a bit. I’ll also lightly clean up the surrounding casting surface and wash it.
I mount a circular cutter on the milling machine, set it on an appropriate fixture plate, and cut elongated holes. Five-degree increments for the elongated holes is more than enough. It looks straight, but it’s actually cut in a circular pattern.
After that, I install everything, remove the valve lifters, and adjust the valve timing. Yoshimura products are solid, so the adjustment goes very smoothly and is a real help.
The pointer for the protractor is still made by bending a welding rod, which isn’t quite ideal. I’ve come up with a cleaner idea, so I’ll make one next time.
Even after doing it many times, I find myself double-checking at least three times on each side, thinking “Is this right?”
First, the cranking force is pretty inconsistent—if you push too hard or don’t push hard enough, it won’t work. And then I wonder if the dial gauge rod is really being pressed firmly enough… Is it slipping or shifting? I get worried and worried…
When the numbers seem off, it often turns out the sprocket wasn’t tightened enough and has backed off.
Since I only do this a handful of times a year like I do, I often end up going “Huh?” But rest assured, the readings end up near the Yoshimura specification values.
Before closing the cover, I double-check everything, pour plenty of engine oil over it, close the cover, and we’re done.
I’ve cleaned up all the fine details too. Now it’s just a matter of cranking it over, starting the engine, and we’re finished.
