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F4i Crank Journal Bearings

Old 11-12-2006, 06:28 PM
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Join Date: Nov 2006
Posts: 2
Default F4i Crank Journal Bearings

Hi everyone,

I was hoping someone on here had some experience rebuilding F4i motors. I cracked open the crankcase to replace a worn shift fork and the damaged drum. I decided to go ahead and change the journal bearings and noticed something odd when I pulled them out. They were all the same. As opposed to the proper bearing being in the proper journal, all journals had C bearings. Is this common practice when people rebuild these motors? The history of the motor is unknown. Right now, I'm assuming the inside has been untouched and it came from the factory like this. Is this even possible? Thanks.
Old 11-13-2006, 03:00 AM
Join Date: Jul 2006
Posts: 87
Default RE: F4i Crank Journal Bearings

Did you have a chance to break out a micrometer and cross reference the main journal and bearing support codes as on page 12-7 and 12-8 of the servicve manual?
Old 11-13-2006, 08:17 PM
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Default RE: F4i Crank Journal Bearings

Yes, and the bearings were all within .01 mm of each other. I haven't been able to check the journals themselves.
Old 10-07-2014, 09:52 AM
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Join Date: May 2006
Location: Prince George's County, MD
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A couple questions:

1- Is there a known weakness in the design or materials of the main bearings on these engines?
2- Is it labor intensive to replace?

I am having some work done to correct someone else's work...and he noted that it may be prudent to replace the bearings. The labor he's quoting seems a bit high to me. I'm looking for a few data points.
Old 10-07-2014, 11:54 AM
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LS1FC3 hasn't been active since 2006....

I don't think he'll get around to answering your questions...-
Old 10-07-2014, 12:53 PM
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Location: Prince George's County, MD
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The question was posed to the forum. I do not consider it relevant if the OP returns to answer or if the answer comes from a new member.

I just hope that the answer is well reasoned and backed by experience.

I need to make a risk-based decision and do not have enough information to reliably do so.
Old 10-07-2014, 02:29 PM
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Perhaps a new thread with more information would generate a discussion that would provide valuable information pertaining to your specific problem. This thread has no substance anyway.

1. Bearings are not a weak point in general. They fail when they are abused.
2. Replacing bearings on anything is labor intensive, if your doing it correctly and measuring everything that needs measurement that is.
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