s1000rr crankshaft/rod bearing clearances

[mrc]

Hi all -- i'm having a hard getting this info from BMW, and the service manual doesn't seem to mention it. Anyone know what the tolerance is for bearing clearance for the main and rod bearings on the crank?

Thnx,
Chris

[mrc]

Originally Posted by mrc

Hi all -- i'm having a hard getting this info from BMW, and the service manual doesn't seem to mention it. Anyone know what the tolerance is for bearing clearance for the main and rod bearings on the crank?

Thnx,
Chris

Since BMW doesn't publish the bearing clearances I decided to determine them myself; and I'm posting them here in case anyone else needs the info.

I plastigaged the rod bearings on a crankshaft from an earlier low mileage S1000rr with red rod bearings using .001 - .003 plastigage. (the rods and bearings were taken from the same bike) The measurements where taken at 90 degrees from the split line of the bearing (should be areas of minimum clearance). All 8 measurements were very consistent at .0015" according to the gauge; and possibly a bit tighter (the next gradation is .001").

I plan on measuring the main bearings when I receive my original crank back from Marine. I expect similar numbers.

Chris

[HOG SLYR]

Thanks for the info! .0015" - .0020" is a pretty common clearance.

[Big Jay]

Running the rods close to .002" and the mains a little tighter ( .0015" seems to work best. When you get the crank back, send it to us and we will balance it to extremely tight tolerance.

APE Racing Crankshafts and Crankshaft Services

[Its4Science]

Originally Posted by mrc

Since BMW doesn't publish the bearing clearances I decided to determine them myself; and I'm posting them here in case anyone else needs the info.

I plastigaged the rod bearings on a crankshaft from an earlier low mileage S1000rr with red rod bearings using .001 - .003 plastigage. (the rods and bearings were taken from the same bike) The measurements where taken at 90 degrees from the split line of the bearing (should be areas of minimum clearance). All 8 measurements were very consistent at .0015" according to the gauge; and possibly a bit tighter (the next gradation is .001").

I plan on measuring the main bearings when I receive my original crank back from Marine. I expect similar numbers.

Chris

You are one of the saints of the internet. I love when people post back their answers for no other reason but to help others.

I'll probably never need the info, but thank you!

[mrc]

Ok, so the saga continues. After BMW told me the green main bearing shells were NLA, I decided to get the old crank repaired (at marine). It came back and looked beautiful. I plastigauged all the main bearings, and they're all dead nuts at .0015".

*** so it looks like all bearing tolerances on the crank (rod and main) are all .0015" for 2010 engine ***


The problem now is that I planned to use the conrods from the mystery ebay crank/rod/piston set I bought, but one of the rod cap bearings got gouged; not a problem, I ordered 2 red bearing shells for this. However, when I replaced the bearing cap, the tolerance went to .002" (it was .0015" before). I then replaced the rod side with the other red bearing, and the tolerance came back to .0015".

The problem is that the manual calls out red bearings for the rod cap, and blue bearings for the rod; but the tolerance is correct with two red bearing shells!

Anyone have thoughts on this? Would there be any reason BMW would call out different bearing halves for the conrods other than to get the tolerances correct? If not, it seems like I'm ok with two red shells if I have the correct tolerance. . .

Chris

Originally Posted by mrc

Since BMW doesn't publish the bearing clearances I decided to determine them myself; and I'm posting them here in case anyone else needs the info.

I plastigaged the rod bearings on a crankshaft from an earlier low mileage S1000rr with red rod bearings using .001 - .003 plastigage. (the rods and bearings were taken from the same bike) The measurements where taken at 90 degrees from the split line of the bearing (should be areas of minimum clearance). All 8 measurements were very consistent at .0015" according to the gauge; and possibly a bit tighter (the next gradation is .001").

I plan on measuring the main bearings when I receive my original crank back from Marine. I expect similar numbers.

Chris

[HOG SLYR]

A couple of questions

You are using the same color bearing in the rod and the cap when you get the latest .00015 reading?

Are you torquing the bolts to spec during the plasti-gauge check and allowing NO movement of the rod or crank?

[mrc]

Originally Posted by HOG SLYR

A couple of questions

You are using the same color bearing in the rod and the cap when you get the latest .00015 reading?

yes. when i replaced the cap with a new red (and the old blue still in the rod), it read .002". I put a new red (i bought 2 halves) in the rod, it read .0015"

Originally Posted by HOG SLYR

Are you torquing the bolts to spec during the plasti-gauge check and allowing NO movement of the rod or crank?

Yes, and mostly. I ordered a new blue half bearing shell and am going to measure it again to be sure. I'll post what I find.

I did talk to Bob at KC BMW, where they're building s1000rr engines for drag racing. He said if the clearance is right, go for it. I also read on the Carrillo site that the Rod big-end bore *doesn't* determine clearance, but it does determine crush (the interference between the bearing and the rod). This makes me think that bearing shell color is just a means to get the clearances correct, and doesn't mean more than this . . .

Chris

[Samsons Revenge]

Originally Posted by Big Jay

Running the rods close to .002" and the mains a little tighter ( .0015" seems to work best. When you get the crank back, send it to us and we will balance it to extremely tight tolerance.

APE Racing Crankshafts and Crankshaft Services

16 years ago, sometime around 1995, I sent you all at APE a crank for a ZX7. I shipped it out next day air on a Friday and requested ASAP work and next day air shipping back. You got my crank on Monday, machined it on Monday, shipped it back out on Monday and I had it back on Tuesday. Pretty Amazing.

It came back 3 pounds lighter, and was balanced perfectly to 14000 RPM's and I spun it that high many times. You fluted the oil holes on the rod main journals as well.

Crank lasted for 1000's of trouble free miles and was later re-sold. Worked perfect!

[BSR-1]

Originally Posted by Big Jay

Running the rods close to .002" and the mains a little tighter ( .0015" seems to work best. When you get the crank back, send it to us and we will balance it to extremely tight tolerance.

APE Racing Crankshafts and Crankshaft Services

I called about work once and was told 4-6 weeks but we can't promise anything...
I found another shop.