Tohatsu m5b crankshaft

[rogros]

How do you keep the two halves of the crankshaft in alignment while pressing the crank pin in on a tohatsu m5b?

 

[pvanv]

You don't normally take the crank apart; That's why they sell the complete crank kit. In fact, the original service manual cautions against disassembling the crank, because it is "very difficult" to retain the alignment when pressing it back together. But, I have seen it done, with a jig to retain the counterweights in alignment while it's pressed. The press must push only on the pin area.

 

[rogros]

Took it apart because the rod bearing was bad.

 

[pvanv]

Took it apart because the rod bearing was bad.

Understood. But the pressed crank is typically replaced as a unit: 369000690M, MSRP is $181.63.
Note that on that page of the parts catalog is the text, "Very Difficult to assemble. The component parts to be purchased as an ASS'Y basically."
If the big end bearing is bad, you probably need a new rod and a new crank pin as well, so it's best, most accurate, and fastest to install the complete assembly.
If you build a jig to retain the counterweights in alignment, then you can press the crank back together.

 

[rogros]

Thanks for the reply.I think I might just part it out don't want to put a lot money in it.

 

[pvanv]

Or, at this point, jig the counterweights and press the crank back together.

 

[rogros]

ok I'll give it a try. Thanks for the info,