Topic: Plastigaging the crank

[timtune]

I have a few old 750-4 honda motors and I want to check the main bearings using plastigage. Does anyone know if I need to torque down every bolt that holds the cases together ( 10mm and 12mm bolts both on top and bottom) or would it be enough to just torque down the 12mm bolts that are obviously holding the crank in place?

Also my book says the clearance is supposed to be  .0008-.0018" and you need new bearings when it's more than .0032". Anyone have a different value?


Thanks

[754]

If you dont torque them, how can you  duplicate actual clearance?

[timtune]

That's my question. Do all those 10mm bolts affect the clearance or is that what the 12mm bolts are for since they are directly over the crank?

[PeWe]

I tightened the 10 crankcase bolts only.  M8 with 12mm heads.
Not the small M6 or the M8, M10 at rear

[pmanning]

+1 for PeWe's reply. It's worked for me through three separate teardowns. Engine now has over 125,000 miles on it with original mains.

[timtune]

Thanks Pewe and Pmanning.

Were you guys both doing a plastigage bearing check? Appearently I can check the con rod big ends with the same plastigage.

[754]

I misread, yeah torque the big bolts,  makes cases are clean.