Well we got the Bruin fixed. Took the carburetor off and gave it a good cleaning. This has to be the most complicated carburetor I've ever seen outside a Rochester Quadrajet! I did not have a good feeling but after cleaning the jets it no longer cuts out and backfires under full throttle. Cleaning gummed up carburetors on stuff sitting around with 5 years of evaporated fuel seems to be hit or miss.
Now onto the front end. Turns out the kingpin was the correct part, everything else was boogered up.
Turned out the rotor and the caliper mounting bracket were bent from where the kingpin had broke. That was why the bottom hole in the caliper bracket did not line up with the kingpin. Also the rotor had wore a groove into caliper, almost through one of the pad pins, halfway through the other and sheared off the peg and the bolt in the caliper mounting bracket.
So we got a used hub with rotor + lug nuts, caliper mounting bracket, new pads and a new pad pin ($9.00!). $72 in mostly used parts.
Yamaha's front brake caliper diagram does not show the bolt. I called the local Yamaha place and the guy seemed clueless at first but lead me to believe you had to buy the entire caliper to get it. OUCH!
So I had to improvise. I would NOT want to do this on car. I had cut 10 mm of this bolt off, install a bunch of nuts, grind the edges off so the caliper wouldn't wobble then to apply Locktite to the threads and adjust the bolt until the caliper was not in a bind. So far so good but I'd still like to fix it right.
The larger piece below is what I need to fix it right.
This link says this piece will not fit a Bruin 350 but it looks exactly like the part. But you know how Ebay's cross reference guide is. Yeah it may only fit a Raptor but it may also fit a Bruin but the seller does not indicate that it does.
Any idea if this bolt will fit a Bruin?