What to look for in a used crank

[wherearewe]

Hi Guys

Got a spare 447 motor i have decided to rebuild. I wasn't planning on doing the bottom end but when i pulled the starter i found some broken gear teeth. Got a really nice replacement gear box so I've decided to totally tear it down.

I noticed the small ends of the rods look pretty worn (little copper left and the piston pins are a bit sloppy).While I'm in there, I'm thinking about the crank. I have a guy who has a lot of spare XS parts & he said go round and pick the one i want. Where i am in NZ, getting a good used one will be heaps easier than a rebuild.

So my question is what expert tips and tricks do you guys have for checking for wear and tear? Carb cleaner on the bearings and feel for grit? Check the small ends for copper condition and pin play and side to side play?

Note. Ive never tackled a bottom end before...

 

[TwoManyXS1Bs]

Yeah, I think you've got the main points.

Carry a spare/new wristpin (gudgeon?) with you to check small end slop.

Look for crank separation, like wear/scrape marks on the flywheel sides, big-end play, non-flush crankpins. A large caliper would help here.

Check the rotor's tapered shaft for damage and woodruff key wallowing. Test the threaded end with a spare nut. Examine the tip of that end for history of rotor puller abuse.

Maybe you could fab an impromptu v-block stand that would allow you to check for obvious runout.

I guess you've seen gggGary's crankshaft thread?

http://www.xs650.com/forum/showthread.php?t=31213