Rod Bearing tech Help

TRNorBRN6001 · 12-20-2007, 4:00 PM

Just curious if anybody can post up crankpin/Rod bearing chart and sizeing.
Trying to figure out what bearings I need to use.

Thank you all much,

Gary

TigreST · 12-20-2007, 4:34 PM

You know this already but,.... I.D. the conrod code, I.D.crank code, measure everything, select the bearing shells that give the required clearance.
This info related to 97 and 98 model XX motor, but should also apply to the later years as well.

Tony

TRNorBRN6001 · 12-21-2007, 8:51 AM

Thank you much, It's for a little 8.5 over stroker LSR/Drag motor.

Plastigauge??? I hear controversey on the issue.

TRNorBRN6001 · 12-21-2007, 4:07 PM

Also curious if you had each of the sizes for the different
colored bearings as well.

Thank You Much,

Gary

TigreST · 12-21-2007, 7:37 PM

The manual does not give the actual spec per bearing color as to what thickness the bearings are, at least not that I've found. But I do have the following to offer up. According to the manual you need to base bearing shell selection so as to maintain the clearance spec between the component parts. The limits are:

Crankpin oil clearance: 0.030 - 0.052mm(0.0012 - 0.0020 inch) with a service limit of: 0.062mm (0.0024 inch)

While we are here we may as well cover off the crank main journal bearing end of things.

Main journal oil clearance: 0.017 - 0.035mm (0.0007 - 0.0014 inch)

The main crank journal bearing selection and related code i.d. info follows in the attachments.

A close look at the spec's shows that there is approx .002 (2 thou) variance in the rod diameters depending on rod code letter, and another .002 (2 thou) diff between the upper and lower end of the bearing color code spec's. The next color offer yet another 2 thou of size change. and so on.

The crank main journal spec's show a similar trend with an extra 1 thou shown for some of the spec's. Have a close look at the charts and you will see the stepped spec change from small to larger.

Regarding Plastigauge,..I do not know of any other means readily available to the DIY (Do It Yourself) mechanic that will give up related info for as cheap as plastigauge can. It may be true to state that the medium is only as good as the hands that put it to use. There is room for error, but then again the engine clearance spec's also are a measurement range of a sort, there is room for a bit of movement.

Some part #'s that may be needed.

Rod bearing part #'s read as follows (on-line source provided these numbers):
Bearing A: 13224-MS2-611
Bearing B: 13225-MS2-611
Bearing C: 13226-MS2-611

Crank main journal bearings are shown as part #:
Bearing A: 13313-MAT-003
Bearing B: 13314-MAT-003
Bearing C: 13315-MAT-003
Bearing D: 13316-MAT-003
Bearing E: 13317-MAT-003

One other item that may bear mentioning is oil clearance for a given motor application. Although Honda have spec's based on the design of the motor they build it may be said that if one takes the motor to some other application that more or less clearance may suit the intended application better then the stock spec's. I can not begin to speak to what those spec's might be for the XX motor in different applications, nor in fact if they should or could be moved based on intended application. Those that race these motors may have a tried and true number that is working for them. Oil system output may effect this clearance selection also. Does the stock oil system put out enough to keep the motor happy in the intended application at a given bearing clearance number. From my DOHC Honda CB-F experiances and that of others the tendence is to go to ward the larger clearance in a bearings range rather then pinch the clearance down to the minimuim end of the spec, as a rule of thumb. XX best practice is lost to me,..I can not comment on this motor in that regard.

HTH.

Tony

TRNorBRN6001 · 08-04-2008, 11:00 PM

Had a delay in the build, but getting on track again.

That is weird that they do not provide a measured size for each bearing. I have had friends that have received bearings for other bikes and when measured do not come to the right color/letter spec in the manual, just accidently mis-labled.

Thanks again,

Gary