How Often You Guy Changing Pistons?


35 replies to this topic
  • mch

Posted September 01, 2014 - 07:41 PM

#1

I should have stuck an hour meter on my 2012 WR450, but I didn't until recently.  That being said, I'm guessing I have 300-400 hours on it.  How often are you guys replacing rings and/or piston?  I was using the mileage as a rough go-by, and checking the valve clearances every 1,000 miles and none were very far off.  I think I had I only had to adjust the same one 2x.  Recently my speedo started showing the wrong speed (like double what I was doing), so that method wasn't too good.



  • JDLowrance

Posted September 01, 2014 - 08:51 PM

#2

You're due. Especially considering your located in Nevada meaning your probably bouncing the motor off the limiter pretty regularly. In those conditions I'd be swapping the piston at 100 hours.

 

I had an 04 YZ450 that I cracked a piston literally in half along the the piston pin axis. Bike was used for desert racing and was continuously at redline. I would guesstimate just over 100 hours on the pistion.

 

Cheers



  • Just_a_trail_rider

Posted September 01, 2014 - 08:54 PM

#3

You need a leak down test to determine when you need to replace your top end.  Do not go by hours or miles.   



  • JDLowrance

Posted September 01, 2014 - 09:05 PM

#4

You need a leak down test to determine when you need to replace your top end.  Do not go by hours or miles.   

 

Not true. Metal fatigues and that can not be detected by a leak down test.

 

The manual states something like 25 hoursor so on piston replacement under racing conditions but that's being very conservative.



  • mch

Posted September 01, 2014 - 09:09 PM

#5

I don't really rev it all that high.  I usually ride it up a gear, and just kind of tractor around at a pretty good pace.  So, if the leak down test is good, what about cam chain?  I figure changing them at the same time would be advisable.



  • vlxjim

Posted September 01, 2014 - 11:41 PM

#6

You don't need a hour meter, It's built in. If you have the Power programer you can read the hours on the ECU.



  • cubera

Posted September 02, 2014 - 01:22 AM

#7

After 80 hours are when my problems start with pistons on CRF or  KTM thumpers. So I'm planning on running the WR piston no longer than that.



  • Just_a_trail_rider

Posted September 02, 2014 - 08:04 AM

#8

Not true. Metal fatigues and that can not be detected by a leak down test.

 

The manual states something like 25 hoursor so on piston replacement under racing conditions but that's being very conservative.

Point taken.     

 

Guys doing hard racing certainly have to have a more strict maintenance schedule.

 

I guess I am assuming that it would be very, very, very rare for the average rider or weekend racer to "fatigue" the metal in the piston before the rings started to show some wear, which would then be detected by the leak down test.   I personally would always change the piston once I got everything apart.   Its hard not to.



  • Krannie McKranface

Posted September 02, 2014 - 10:24 AM

#9

Once a year / 200 hours, which ever comes first.



  • underground-mpyre

Posted September 02, 2014 - 12:36 PM

#10

WOW!!! This is first I have heard about changing the piston or rings frequently. Remember my 426 is my 1st Dirt Bike, so I don't know all the maintenance on them(mostly sportbikes and vintage bikes). I also bought it used in May.

 

I know about to check the valves and changing the oil every 200-300 miles. But changing the piston or rings seems like a lot of work to do yearly or over so many hours and I am sure I will have to pull the entire motor, since the PO didn't tell me if this was ever done. WTF?!



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  • Krannie McKranface

Posted September 02, 2014 - 01:24 PM

#11

All high performance motors are like this

If you race ( I mean RACE) then you usually change the piston/rings every few races.

I would not recommend waiting 300 miles for an oil change! That's too long, unless you are doing Baja.....or all street.

Street riding does not put much stress on the motor at all....unless you are getting a ticket a week...

 

 

You should really get a Service Manual and read it.



  • underground-mpyre

Posted September 02, 2014 - 01:28 PM

#12

I have a service manual and haven't seen it in there to change that or oil. Though the valves I have seen.



  • KennyMc

Posted September 02, 2014 - 06:33 PM

#13

Once every 5 years (6 years but I was down after rotator cuff surgery for a year), ~500 hours or a bit more. Only done 1 since inception, 2007 - current.

  • Krannie McKranface

Posted September 02, 2014 - 07:32 PM

#14

Once every 5 years (6 years but I was down after rotator cuff surgery for a year), ~500 hours or a bit more. Only done 1 since inception, 2007 - current.

 

Yes, and ken had 17  hp too....!  :naughty:


Edited by Kah Ran Nee, September 02, 2014 - 07:32 PM.


  • Just_a_trail_rider

Posted September 02, 2014 - 09:37 PM

#15

WOW!!! This is first I have heard about changing the piston or rings frequently. Remember my 426 is my 1st Dirt Bike, so I don't know all the maintenance on them(mostly sportbikes and vintage bikes). I also bought it used in May.

 

I know about to check the valves and changing the oil every 200-300 miles. But changing the piston or rings seems like a lot of work to do yearly or over so many hours and I am sure I will have to pull the entire motor, since the PO didn't tell me if this was ever done. &%$#@!?!

Changing a piston is not that hard and not the expensive.   Get a leak down tester....  that is the way to go despite what all the would be hard core racers / bike abusers would have you do.      

 

On the wr450 I used to have, I went well over 5 years and 700 hours before I changed my first piston or ring.  I raced the bike (If you wanna call what I do racing) and I dual sported and trail rode a lot.    The bike was running perfectly before I changed that piston and it only really needed rings.   Your results may vary.



  • underground-mpyre

Posted September 03, 2014 - 04:26 AM

#16

Ok, I will buy a leak down tester to find out where I sit with the piston. What are the tolerences?

 

I am sure I have to pull the whole motor out to change the rings and/or piston. Where is a good place to purchase Rings and a piston cheap? What other tools do I need like piston rings sleeve collar or what?

 

Winter is coming, might as well for security measure do this if it is that important.



  • beezer

Posted September 03, 2014 - 05:15 AM

#17

I would just ride the thing and stop worrying.

 

When the valves tighten up the bike gets hard to start.

 

If the oil is changed and the air filter is kept clean the bike will run for ever.



  • Pooley

Posted September 03, 2014 - 05:32 AM

#18

I have changed the rings on my 01 WR426 twice now, and the actual piston only once, although it didn't need it at the time.  I estimate that I have roughly between 13,000-15,000 miles of singletrack on my bike since 2001.  When I changed the rings and piston, it was at 8,000ish miles after dumping the bike in a creek and sucking water into the engine.  This was the first time the bike had any engine work.  I just changed the rings this weekend just for the fun of it while re-assembling the head after a valve job.  The piston looked great so I didn't change it.  If you are a weekend-warrior type of rider who does not race, doesn't bounce the rev-limiter constantly and doesn't beat the living hell out of the bike in general, the longevity of Yamaha motors can't be beat.  They are dead reliable and bombproof IF you take care of them.  Do your oil changes, air filter, replace wear items like chains, sprockets, cables as necessary, and the periodic checks like valve lash, cylinder leakdown, etc and fix when it needs it, don't go by factory or race-specs unless you have a bottomless wallet.  BTW, don't go cheap on parts for the engine, buy OEM parts.  You can get stuff from the TT store for a discount, and if it is out of stock at the TT store and/or they don't have an item, Bikebandit.com is another good site.


Edited by Pooley, September 03, 2014 - 05:35 AM.


  • underground-mpyre

Posted September 03, 2014 - 06:25 AM

#19

Thanks Pooley, once again you are direct with the detailed proper needs to be done for this beginner and let me worry less. I plan on a leak down this weekend and go from there. Thanks everyone else for their input too.



  • Just_a_trail_rider

Posted September 03, 2014 - 06:54 AM

#20

After 80 hours are when my problems start with pistons on CRF or  KTM thumpers. So I'm planning on running the WR piston no longer than that.

You got 80 hrs out of a KTM piston?   I could only get 60hrs on my xcf before oil flow issues started chewing up my cam journals and the cams and everything else.    Three expensive rebuilds in three years with very little riding  :banghead: .   (wait...   this is not the KTM thread...)   Back on topic...  

 

When I had my 05 wr, I easily got over 500 hrs with no valve adjustments   The bike just kept running and running.     IMO, 80 hrs is way too soon to be worrying about a wr450.






 
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