Joemi

Is it necessary to change every engine bearing on a rebuild?

9 posts in this topic

I'm currently in the middle of giving my two stroke motor a full overhaul because the big end rod bearing is worn.

I'm just curious how many of you replace every single bearing in the engine while it's split or if you only replace them if they show signs of wear/damage?

Share this post


Link to post
Share on other sites

Normally, all trans bearings live as long as the engine. I just check and any play,rouchness/signs of damage, then replace. Crank bearings I change every time the crank is changed or rebuilt as well as if there is any signs of play, roughness or damage.

5 people like this

Share this post


Link to post
Share on other sites

William has it right..

I would also like to add that changing out any good Honda bearing for new CHINA made JUNK is WRONG! WRONG! WRONG! I'd rather have a 20 year old Honda bearing with 100,000 miles on it than a brand new China made, soft, improperly machined, not heat-treated, out-of-round, piece of you know what.

If you do end up changing ANY bearings, please, ONLY use genuine Honda, or bearings from another WELL KNOWN, HIGH QUALITY, manufacturer. Beware ANYTHING that comes out of China. Do not trust ANY China made internal engine parts-EVER! In my business we are seeing more China made junk coming to our parts counters and it really is just useless garbage. But, people want the lowest price.. They never factor in what it costs to tear an engine down a second time to replace the China junk they installed the first time because it saved them a little money over genuine, quality, parts. Trust me I've used a "complete bearing kit" to replace all of my bottom end bearings. The last time I had my engine apart those "new" bearings were already so sloppy that I had to change them out again. Luckily I caught them before they failed. I was replacing my crank and decided to check those bearings again since I had the cases split. Now, I only have HONDA bearings in my bottom end again. Try and find FAG, or Timken bearings. SKG is now CHINA made so beware. They might be good, but why gamble on something so hard to replace if it fails shortly after install?

1 person likes this

Share this post


Link to post
Share on other sites

Posted (edited)

1 hour ago, Kawabuggy said:

William has it right..

I would also like to add that changing out any good Honda bearing for new CHINA made JUNK is WRONG! WRONG! WRONG! I'd rather have a 20 year old Honda bearing with 100,000 miles on it than a brand new China made, soft, improperly machined, not heat-treated, out-of-round, piece of you know what.

If you do end up changing ANY bearings, please, ONLY use genuine Honda, or bearings from another WELL KNOWN, HIGH QUALITY, manufacturer. Beware ANYTHING that comes out of China. Do not trust ANY China made internal engine parts-EVER! In my business we are seeing more China made junk coming to our parts counters and it really is just useless garbage. But, people want the lowest price.. They never factor in what it costs to tear an engine down a second time to replace the China junk they installed the first time because it saved them a little money over genuine, quality, parts. Trust me I've used a "complete bearing kit" to replace all of my bottom end bearings. The last time I had my engine apart those "new" bearings were already so sloppy that I had to change them out again. Luckily I caught them before they failed. I was replacing my crank and decided to check those bearings again since I had the cases split. Now, I only have HONDA bearings in my bottom end again. Try and find FAG, or Timken bearings. SKG is now CHINA made so beware. They might be good, but why gamble on something so hard to replace if it fails shortly after install?

Thanks for the information. I only ever trust bearings that are recommended by manufacturer or have made in Japan stamped onto the race personally. I swear by KOYO or SFK bearings with previous experience!

Edited by Joemi

Share this post


Link to post
Share on other sites

You are gonna pay to have the crank pulled apart and reassembled and not replace a $20 bearing?  That makes no sense.  If the crank is coming apart, replace every bearing associated with it, along with the seals.  

1 person likes this

Share this post


Link to post
Share on other sites

I replace every bearing and bushing that is within the cases if the engine has unknown hours or has several hundred. I look at as I don't want to split the cases again for a long time and especially not because a $20 bearing failed. I also only use OEM bearings/bushing within the cases. Do it once, do it right!

 

4 people like this

Share this post


Link to post
Share on other sites

I do not replace trans bearings just because I'm in there.  No need.  Excellent point above about good used stock bearings VS replacements of unknown quality.

Main bearing, crank seals and a crank if necessary.  Unless something very bad happened to the trans those bearings will be fine.  This is a situation where the less you screw with the better off you will be.

2 people like this

Share this post


Link to post
Share on other sites

Not mentioned yet, but NTN bearings (stock in Kawasaki, not sure of other makes) are the best bearings made. This is, at least, the opinion of a local bearing distributor.

1 person likes this

Share this post


Link to post
Share on other sites
On 12/08/2017 at 8:45 PM, CDNSXV said:

You are gonna pay to have the crank pulled apart and reassembled and not replace a $20 bearing?  That makes no sense.  If the crank is coming apart, replace every bearing associated with it, along with the seals.  

I had this state of mind but it's more like £80 and a 2 week wait for KTMs strangely sized final drive bearing... 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


  • Similar Content

    • By hondatwister
      im looking to buy a cylinder that will fit a 98 kx250 u purchased a bike that doesnt have one at all so i need one complete with the power valve setup as well. if you know where one is or have one or any other kx250 parts let me know
    • By jpcaston
      Have a 2015 YZ125.  After a rather bad crash I had to replace the subframe and air box.  I put it all back together. Kicked for 5 minutes  Wouldn't even come close to starting.  Had been sitting for 6 weeks or so, so I checked and Got spark, got compression, got new plug(old one showed proper color, not lean), got gas supply to carb. Anyway I lay the bike on its left side for a highly technical excess fuel purge and first kick with fuel off and zero throttle, it starts but have runaway engine condition.  Had to use kill switch to stop it before it blew up. I have been reading that it could be crank seals or another type of air leak.  Not really buying that because why would it start right up after simply laying it on its side.  New air box should be sound and sealed.  Anyway I would think the air leak if it's that is after the carburetor.  On the YZ there is only the reed valve after the carb.  I'm thinking crud in the carb but on a dirt bike you would think that would be a more common condition.   Anyway, looking for ideas here. 
    • By Mason Mayhall
      Whats up everyone I'm pretty new to the forum so I'm not sure if I'm posting in the correct spot.Either way I need some help! what year kickstart levers will fit my 2007 yz450f. I got away with a Kim lever off a 525 exc but now I'm looking online and can't find much but one option for 130$ I'm seeing a lot of options for 2011 levers around 75$ and they look nicer with a blue instead of silver. Does anyone know what size the spline is? what other years I could possibly use? thanks in advance. On another note my oil filter housing bolt is stripped like most I see are dealing with. I have googled away and cannot seem to find where to order that bolt. 
    • By LeeHoudini
      names of people who rebuild engines, heads, etc through the mail please. I have taken the advice of several people here on Thumpertalk and fired my mechanic. This is a small town and my old mechanic is buddy buddy with all of the others so when i need to get my head or complete engine rebuilt i will have to send it to soneone. Thanks
    • By CatXR
      I bought a 2001 xr200r bike as a project and am in the process of rebuilding it. I have never rebuilt a bike before, only automotive engines and was intrigued by the versatility and challenge of doing something I've never done before, plus who doesn't want a dirt bike?
      I have been told that I can bore out the cylinder in order to accommodate an xr250r piston. I have done research on the differences between the two motors through schematics and specifications, but I still have some questions and concerns.
      1. Is an xr250r top end compatible with an xr200r bottom end?
      2. Is rejetting the xr200r carb enough or should I upgrade to a xr250r carb and fuel tank?
      3. Can it remain a two valve system or would I rebuild the whole top end with a xr250r 4 valve?
      4. Dry sump vs. wet sump?
      5. Is it worth the power difference?
      6. Higher performance bearings in the bottom end to handle the power difference?
      7. Available kits or call a machine shop?
      Like I said, this is the first time I have ever done this so inexperienced is a kind way of saying I'm pretty in the dark here, but looking to learn and build a beautiful machine for next season. Any input is greatly appreciated! Thanks!