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Topic-icon Connecting rod big end bearings only

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3 months 1 week ago #4794 by 14979
Hello,
I've rebuild many motors over the years from Chevy 396big block to Nissan 1.5l and a few bikes but never had an airhead case apart.
I'm looking a clean 1983 R100RT with Spyder sidecar. I got my hands on some 2009 dealer repair work records. This bike had the big end rod bearing replaced, bolt, and other misc, BUT they are standard size and no evidence of any type on machining. I'm sure they didn't split the block.
I've heard of folks just replacing big end bearing in the bock but I've only done it in the context of a complete rebuild. I suppose I'm leery of this but I suppose if the could check the crank journals and get the proper gaps.

This rod work was done as part of a Low Compression complaint, they also set the heads out for (OMG) $914 of work!

What are your thoughts?

Thanks
Edward

1981 R100RT

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3 months 1 week ago #4795 by Wobbly
Replied by Wobbly on topic Connecting rod big end bearings only
You didn't say how many miles the odometer was showing. However, with that much head work it must be extensive.

The best test is to crank it and ride it with an oil pressure gauge attached. The warm engine oil pressure both at idle and road speeds will tell you a great deal about the conditions of the rods and mains together. The only way to know about their independent conditions is to disassemble and measure.

Don't hide 'em, Ride 'em !!
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3 months 1 week ago #4796 by 14979
Replied by 14979 on topic Connecting rod big end bearings only
The bike has 41,700 indicated with the work being done about 800miles ago.

Very true about oil pressure checks but unless there is a gauge already connected, owners get a sticky about unbolting the idiot light switch to screw in my own gauges.

I'll take my mechanics stethoscope and listen closely.

I'm more curious about simply changing the big end bearings only.
Thanks
Edward

1981 R100RT

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