Topic: Crank main bearings too tight?

[PeWe]

I think the bearings are wrong. They have been in appr. 30.000km

Crankcase is stamped BBBBB. Crank is AAAAA, verified with micrometer (all about 35,9995mm).
Only one strange thing, the journal at the pointside is cone shaped from outside 35,995-36,010. (36,000 should be max) I measured several times with high quality tool Micrometer 25-50mm.

On 2 bearings I could see brownish stains where the color code should be, BROWN.
GREEN is correct according to the manual. A crank, B case.

They look to have been a little bit tight, right?

[lucky]

WOW   .010 taper!!!  Better get that taken care of.

[bryanj]

Forget the colour on the shell, they all look brown after a few heat cycles

[PeWe]

WOW   .010 taper!!!  Better get that taken care of.

Yes, 0.010mm.. maybe not that much.. 1/100 of a millimeter.
Strange when all the other had the same numbers wherever I checked. I could not see any specific damage on corresponding bearing.
Photo "Lower crank...", 1st bearing from left at ignition side, thicker to the right side of the journal

Anyway the close-up show a bearing that has to be replaced, right?

The bearings might have got extra damages when the engine has not been running with oil pressure, only manual revs with kickstarter once a year during almost 19 years to avoid pistons become stucked. Years after the oil has left the surface maybe...

The complete set of bearings are OK to order at this side of the Atlantic Ocean. http://www.cmsnl.com/products/brg-crankshaft_13315425003/
100€ for a complete set..
no extra tax for part + shipping by factor 1,3  as when I order from countries outside EU.

[bryanj]

Personaly I would say that for a standard, untuned, motor those shells are fine, spend the cash on new rubber bits in the camchain tensioner mechanism as those parts age badly

[lucky]

WOW   .010 taper!!!  Better get that taken care of.

Yes, 0.010mm.. maybe not that much.. 1/100 of a millimeter.
Strange when all the other had the same numbers wherever I checked. I could not see any specific damage on corresponding bearing.
Photo "Lower crank...", 1st bearing from left at ignition side, thicker to the right side of the journal

Anyway the close-up show a bearing that has to be replaced, right?

The bearings might have got extra damages when the engine has not been running with oil pressure, only manual revs with kickstarter once a year during almost 19 years to avoid pistons become stucked. Years after the oil has left the surface maybe...

The complete set of bearings are OK to order at this side of the Atlantic Ocean. http://www.cmsnl.com/products/brg-crankshaft_13315425003/
100€ for a complete set..
no extra tax for part + shipping by factor 1,3  as when I order from countries outside EU.

Years after the oil left the surface? Maybe. I would want to see if those journals polish up easily first. Once oil gets in the space between the crank and the rod bearing  it should stay there.
BTW There have been forum members with low mile engines that  thought they could just service the fluids and run the engine again and then the small bits of rubber start showing up in the sump and filter from the old cam chain rollers that got dried up and hard after sitting for many years.

[PeWe]

I found lots of small pieces of rubber in the oil pan at right side of the oil pump mesh. Both tensioners replaced to season 1984, last year I used the bike  was 1990. So I wonder what all rubbish rubber comes from.  Tensioners really that bad?
They were OK 1985 when I took out the crank, new (old OEM) rods, pistons and balanced it at local workshop. I assembled it.

Maybe I dropped some rubber last time I had the engine open, 1987? A hard piece of broken clutch plate (20mm long) could have cut som rubber off.

It's a good idea to remove the oil pan every year when changing oil to verify the health and not stucked oil pump mesh.

I have ordered a new OEM tensioner for Primary chains, Cycle X racing tensioner for cam chain. I'm actually put new bearings in the basket right now     Have to check everything else I need from the same site.

[PeWe]

I have new bearings soon flying my way. I made a mistake when ordering and I'm lucky it was possible to change the order.

When order bearings, be sure about the part number before and do not think about your crank A,B,C,D or case A,B,C,D .
You must know the partnumber.

I have case B and crank A for all 5x2 bearings.
This is green marked bearings that is named BRG C,CRANKSHAFT (13317-300-013)

I was thinking about my crank too much so I had letter A in my mind so I ordered A... BRG A,CRANKSHAFT (13315-300-013)
When I found out that that part no is black bearings I called direct and could happily change the order. I found out 10 minutes after order.

I hope this will help others to avoid same mistake as I made.

It is a little bit confusing A/B/C/D  case + A/B/C/D  crank = A/B/C/D bearings very clear described in the manual that has a chart with part numbers for the bearings.