how tell if your crank needs rebuilding?

[bign1514]

I am in the process of rebuilding my engine, and took a look at the crank. Now, all the bearings spin pretty good (nice and smooth & a lot of rotations). I have one bearing on the middle side that is smooth spinning, but doesn't like to spin as much as the others.

What could this be a sign of? Anything to be worried about?

thanks


ps. its an 62t 701 OEM crank

 

[chrisdoc0608]

if it is smooth, quiet, and there isnt pitting or play in the bearings i wouldnt worry abt it for a rec motor.

 

[bign1514]

im putting some money into this.... have a fresh freestyle port job (LWP) and new pistons.

don't want the crank to go out mid season and have to re-due everything.

 

[BombThreat]

i was in the same situation as you... not being really able to tell if a crank is A-OK I just sent it along with all my parts to be get worked on at the engine builder. have him inspect it and let me know..

 

[chrisdoc0608]

well personally if i spent the money on the port job and pistons i would go ahead and replace the crank and seals for piece of mind

 

[keefer]

The main bearings need to spin freely & quietly but you should be more concerned with the big end rod bearings. Have someone with the proper gauges check the side clearance of these and the trueness of the crank. This might give you a better indication of the cranks general health.