When your crankcase main bearing journals are worn :-(

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Sandblaster
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When your crankcase main bearing journals are worn :-(

Post by Sandblaster » Fri Oct 20, 2017 2:28 pm

kx guru racing kx500 bearing journals are junk.jpg
kx guru racing kx500 bearing journals are junk.jpg (230.64 KiB) Viewed 1322 times

As the KX500's get older and older we see many that have had the main bearing journals in the crankcases worn out.
We have seen many different repair methods.
Some people use a punch or chisel and work over the ID of the journals.
That caused material to mushroom out and takes up the clearance.
Another fix is to use retaining compound and glue the bearing in.
Some have bored the journal out and shrink fit a small sleeve in.
We usually take ours in to a industrial plating facility and have the ID build back up to factory specs which is the longest lasting out of all these options.
For years we have heard rumors of a bearing that you can get that allows you to bore the journals out and then light press oversized bearings in.
But I never could find the bearings.
I was on Facebook and mentioned this situation and sure enough one of the members at KX Guru Racing Troy Cooper, said the following: "Machine out and run trx 450 mains. Common modification".

I looked up the bearing size and here it is 30X76X19
Honda P/N 91001-HP1-601

The stock KX500 main bearing is 30X72X19

Fits the following:
Honda ATV 2006 TRX450ER A CRANKCASE ('06-)
Honda ATV 2006 TRX450R A CRANKCASE ('06-)
Honda ATV 2007 TRX450R A CRANKCASE ('06-)
Honda ATV 2007 TRX450ER A CRANKCASE ('06-)
Honda ATV 2007 TRX450ER 3A CRANKCASE ('06-)
Honda ATV 2007 TRX450R 3A CRANKCASE ('06-)
Honda ATV 2008 TRX450ER 3A CRANKCASE ('06-)
Honda ATV 2008 TRX450ER A CRANKCASE ('06-)
Honda ATV 2008 TRX450R A CRANKCASE ('06-)
Honda ATV 2008 TRX450R 3A CRANKCASE ('06-)
Honda ATV 2009 TRX450R A Crankcase
Honda ATV 2009 TRX450R 3A Crankcase
Honda ATV 2009 TRX450ER A Crankcase
Honda ATV 2009 TRX450ER 3A Crankcase
Honda ATV 2012 TRX450ER 3A - TRX450ER Crankcase
Honda ATV 2013 TRX450ER AC Crankcase
Honda ATV 2013 TRX450ER 3AC Crankcase
Honda ATV 2014 TRX450ER AC Crankcase
Honda ATV 2014 TRX450ER 3AC Crankcase

Looks like a winner!
Thanks Troy.
If bikes are for kids I'll never grow up.

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Sandblaster
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Re: When your crankcase main bearing journals are worn :-(

Post by Sandblaster » Fri Oct 20, 2017 3:08 pm

There should be .0015" to .0020" interference fit at room temperature for the bearings to be tight when the cases, bearings and crankshaft are up to operating temperature.
If bikes are for kids I'll never grow up.

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Sandblaster
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Re: When your crankcase main bearing journals are worn :-(

Post by Sandblaster » Fri Oct 20, 2017 3:12 pm

Some claim that the Suzuki LT500 bearings will also work.
IF that is true (I have not verified the bearing size yet) then these should fit.

Suzuki P/N 09262-30076

Suzuki ATV 1987 QUADRACER - LT500R Crankshaft
Suzuki ATV 1987 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1988 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1989 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1990 QUADRACER - LT500RL Crankshaft
Suzuki Motorcycle 1978 SP370 Crankshaft
Suzuki Motorcycle 1980 GN400T Crankshaft
Suzuki Motorcycle 1980 GN400TX Crankshaft
Suzuki Motorcycle 1980 GN400XT Crankshaft
Suzuki Motorcycle 1979 SP370 Crankshaft
Suzuki Motorcycle 1980 GN400XX Crankshaft
Suzuki Motorcycle 1980 SP400 Crankshaft
Suzuki Motorcycle 1981 GN400T Crankshaft
Suzuki Motorcycle 1981 GN400XX Crankshaft
Suzuki Motorcycle 1981 GN400TX Crankshaft
Suzuki Motorcycle 1981 GN400XT Crankshaft
Suzuki Motorcycle 1982 GN400T Crankshaft
If bikes are for kids I'll never grow up.

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Sandblaster
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Re: When your crankcase main bearing journals are worn :-(

Post by Sandblaster » Fri Oct 20, 2017 3:17 pm

Found another 8-)

This Honda 91001-MEY-671 BEARING, RADIAL BALL (30X76X19) fits the following models and components:

Honda Motorcycle 2005 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2005 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2006 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2006 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2007 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2008 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2009 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2012 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2013 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2014 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2015 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2016 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2017 CRF450X AC - CRF450X Crankcase
If bikes are for kids I'll never grow up.

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