Crank/ bottom end

[Cooldean69]

What’s up everyone, how many miles can you expect to get out of a bottom end before the crank is out of true or the bearing goes south? I know there are many types of sportster bottom ends (early ironhead, amf ironhead, evo 4 speed, evo rigid mount, evo rubber mount, etc…)

I guess my question would be how many miles is too high when buying a used sportster? Found a good deal on a 99 883 but how many miles is too many before you should worry about the bottom end? I know I need to measure runout to see how out of true the crank is but is there a rule of thumb on mileage? Lots of guys in other threads said well over 100k Any insight would be appreciated thank you

[farmall]

If it runs fine, ride it. Evo cranks easily go over 100K miles. You don't need to measure runout unless you've torn the engine down. Runout checks are mostly for Twin Cams when evaluating possible gear drive cam installs but that bottom end is very different.

No knocks, no smoke, good compression? Enjoy. If installing a bore kit inspect connecting rod play etc.