Rebuilding the bottom end questions

[mustang]

Hi just joined up this is a great site just have a few questions

I have a 2004 yamaha warrior and it has a seized rod bearing. I ordered the hot rods crank and am about to install it. just wondering what causes rod bearing failure ? The oil pump seems to be ok it spins but it has a little resistance when i spin it. Should i replace it while i'm doing the rebuild ?

Also, the piston and rings and jug are fine the wrist pin looks perfect, I know it would be a nice complete rebuild to change it but just low on funds after the $400 for the crank and gasket kit. so would you change the piston and do a hone ?

And one more thing, the starter clutch one way seems to be jammed on the ring gear, can i knock it loose or should i replace it. it doesnt spin either way its stuck with the stator magnet.

Thanks

 

[Gen1Pat]

Most times if the rod bearing is siezed it is due to lack of lubrication. All rod bearing will wear out and get excessive play in them over time, but for one to sieze the most likely culprit is lack of lube. If play is extremely excessive, a needle could have gotten bound in it's cage and caused it to lock up. Clean and make sure that all oil passageways are clear of obstructions. Submerse the oil pump in some oil and spin it over. That way you can see for certain that it will pump. You can also look up the service limit's wear specs and check them with the appropriate feeler gauge. But, if you have doubt about it, replace it. I always go with my gut, and if my gut says don't trust it, I don't. As far as the piston is concerned, if it is in good conditon, and the cylinder is in good shape (no scoring or out of round/within the wear limit) and can be honed, just install new rings. And be sure to check your ring end gaps. Adjust them if needed.