Lower End Assembly Help - Crank hard to turn

[joeym4130]

Greetings, I am trying to put my bike back together, I replaced the bearings in the cases and it came time to put it back together tonight.

I froze the crank and heated the bearings with a aluminum slug on the inner race of the main bearings, and put the crank in. It went in the one case side easy enough, and I lowered the other side on it.

It all went down pretty easily, but once I started closing the little gap left in the cases, the crank got harder and harder to turn.

If I snugged the case bolts up to any decent amount, the crank is REALLY hard to turn by hand.... I dont know what I'm looking for here. I tried using a rubber mallet on the crank *very lightly* ( i'm not sure how hard to whack it)

I dont know what a checklist of causes could do this, perhaps a main bearing not completely seated in its place?

I appreciate any assistance! I'm stuck!

 

[kx125412]

I was reading my friends service manual for his kx and if I remember right it said it was normal for it to be tight until everything was completely together. I could be wrong hopefully someone else could be of better help.

 

[joeym4130]

Yeah I had a printout from eric gorr's site from a while ago about assembling bottom ends, and it mentioned about having some resistance while turning, but mine is like you need to have 20" forearms of a strongman to turn the thing haha! Which I have a feeling something isnt right in there, I just don't know where to start troubleshooting because I took my good time putting everything in...

 

[joeym4130]

How much resistance should there be on the typical newly installed crankshaft?

For an update, I heated the case up and gave the crank a few more taps and it is spinning a tad easier now, but I'm not sure how much resistance there should be w new bearings/seals and all that.

 

[JBarrett]

It sounds like the crank isn't seated all the way into the bearings.

 

[2strokerfun]

Sounds like something could be warped a bit. Try splitting cases 1/2" or so and start to torque back together about 1/2 turn at a time on the case bolts in the correct order. You might also double check the bearings are the correct part numbers.

 

[joeym4130]

Sounds like something could be warped a bit. Try splitting cases 1/2" or so and start to torque back together about 1/2 turn at a time on the case bolts in the correct order. You might also double check the bearings are the correct part numbers.

Ill try opening it up and doing it again.

The transmission shafts spin easy

The bearings are the right ones too, I took my good time making sure I did it right.

Maybe opening her up and redoing it will set it right.