can anybody decode the numbers on the main crank bearings to size of the bearing???

[90-666]

the numbers stamped on the crank main bearing is FA130 Y8J it's a NDC bearing off of a DOHC BP thanks

[FestYboy]

It doesn't show up on their catalog.

Are you wondering if the bearings are undersized?

[90-666]

yes so i can order new ones is there a way to find out?

[milehighbear]

Can't you take em to a garage and have the mechanic mic em to see what size and go from there.

[FestYboy]

It is beyond unlikely that the mains have been turned down on the bp seeing as the bearing manufacturer you listed is what would have been used for initial assembly... Aka, a factory bearing.

[90-666]

do you know what the standard size bearing thickness is i have a mic

[90-666]

the top bearing has FA130 939B on it

[FestYboy]

The bearing size is determined by the journal diameter. If you have a mic, take an ID measurement of the main bore and an ID measurement of the journal, and subtract ~ .003 then decide the sum in half, that's the bearing thickness. There should be ~ .003 difference the ID of the bearing and the journal. Measure the bearing installed and torqued.

[90-666]

so measure without the crank in place right?

[FestYboy]

Yes

[90-666]

thanks for the help i have rebuilt top ends before but this is the first time doing a bottom end

[FestYboy]

My pleasure. If you have any questions, don't hesitate to ask.