Inner crank bearing failure?

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JonW
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Inner crank bearing failure?

#1 Post by JonW » Thu Dec 20, 2018 8:30 pm

The PO took the engine out of my bike as he had read / heard that the inner crank bearings can destroy themselves at around 40,000 kms (25,000 miles).

I guess my question is; Is this something that is well known as a failure with these engines at this milage?
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silverstrom
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Re: Inner crank bearing failure?

#2 Post by silverstrom » Fri Dec 21, 2018 12:13 am

That is what my information says Jon, but I wouldn't bet on it. Any bearing will last only as long as it's operating in an ideal environment. Use poor quality oil and suddenly you lose longevity. Overspeed the crank and you lose longevity. There are many ways to shorten the life of any bearing. Unless you bought the bike new and put every km on it yourself it's safe to assume the cranks haven't been well cared for.

Splitting outer bearings is a bigger concern and a known problem.

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JonW
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Re: Inner crank bearing failure?

#3 Post by JonW » Fri Dec 21, 2018 12:43 am

I do agree with you John, any used bike is an unknown quantity of course.

So the outer ones split? eeek... they have an oil pump and yet still do that... weird.
www.2smoked.com

80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD250LC '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

silverstrom
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Re: Inner crank bearing failure?

#4 Post by silverstrom » Fri Dec 21, 2018 3:14 am

I think it has something to do with the locating pin on the inner and the located groove on the outer.

This post discusses a split centre bearing and farther down the page a RH outer bearing. http://www.rzrd500.com/500phpBB3/viewto ... ing#p75494

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JonW
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Re: Inner crank bearing failure?

#5 Post by JonW » Fri Dec 21, 2018 4:17 am

Cool, thanks John. I have no option but to split this one then since its done 25,000 miles. I'll see what's inside and go from there I guess.
www.2smoked.com

80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD250LC '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

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