Should I try to put a new piston/rings myself?

15 replies to this topic
  • DoctorRzed

Posted November 25, 2004 - 04:16 AM


I never did this before and I could save about $200 from labor cost from the dealer. And I can get the piston/rings/gaskets for around $120. I wanted to put a wiseco piston in it? What tools do I really need? I have all the bacics?

  • bushy

Posted November 25, 2004 - 06:25 AM


Yes you can definetly do it. I'm 15 and I have already put new valves in my bike by myself.

All you really need aside from normal tools is a ring compressor which could be rented for a few bucks or borrowed from a friend. You may really not need it, some people just compress them by hand.

After you've had the top end off once, its a sinch to do next time. Just follow the manuel, its quite descriptive and helps alot.

  • MXof21

Posted November 25, 2004 - 06:31 AM


It is not a difficult job but you will definataly need the shop manual. You will also need a torgue wrench in inch pounds to reasseble the cam journals and proper feeler guages for checking valve clearance. If you have ever adjusted valve clearance that is the toughest part of replacing the piston and rings. I have never used a tool to compress the rings and have not had a problem.

  • DoctorRzed

Posted November 25, 2004 - 07:54 AM


I have a ring compressor and I have a digital torque wrench. I am worried about the piston circlip and geting the piston/rings in the cylinder correctly :cry:

  • BC3

Posted November 25, 2004 - 12:48 PM


Taking into consideration that you have good mechanical skills I would say go for it (with a factory manual) If you have any doubts about cam timing and how it works.......don't attempt this job without supervision from someone that has done it before. You will still save money but more important you will learn the correct way to complete this job.

BC :cry:

  • beezer

Posted November 25, 2004 - 05:38 PM


If you are worried about the circlip get a pair of snap ring pliers.

  • smokin529

Posted November 25, 2004 - 07:50 PM


It's always a good idea to put clean paper towels around the rod to keep anything from falling into the bottom end. If you do that, you won't have to worry if the snap rings go flying! Take your time and follow the manual. Doing a top-end on a 4-stroke is easy, JUST TAKE YOUR TIME AND FOLLOW THE MANUAL. After you do it once, the next time will take half as long.

  • yz426onNOS

Posted November 25, 2004 - 08:26 PM


It takes me about 30 min.

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  • FFRacing79

Posted November 26, 2004 - 07:59 AM


It takes me about 30 min.

Start to finish?? :cry:

  • FFRacing79

Posted November 26, 2004 - 08:04 AM


The easiest way to install a new piston is to put it into the cylinder on the bench. Install it from the bottom side and no ring compressor is required. If you do use a ring compressor, turn the band upside down(they are tapered) as most are made for automotive use and auto pistons are installed in the top of the bore, just the opposite of M/C pistons.
Also the manual calls for 8 ft/lbs of torque for the cam journals...this is TOO much. It is possible for the journals to distort and cause the cams to gall. Reduce it to 5 ft/lbs or 60 in/lbs. Tdub

  • beezer

Posted November 26, 2004 - 01:57 PM


30 minutes to do what?

  • Bryan47

Posted November 26, 2004 - 11:34 PM


30 minutes to do what?

Heh heh, that's a LOADED question! :cry: :cry:

  • SXP

Posted November 27, 2004 - 10:15 AM


It takes me about 30 min.

Rriiiiigghht :cry:

  • bushy

Posted November 27, 2004 - 01:45 PM


I could change my sparkplug in 30 min :cry:


  • RAD

Posted November 28, 2004 - 10:37 AM


Remember don't use the synthetic oil for the first ride till the rings seat. Then go to the good stuff. That way the rings won't glaze over.

If you use Yamalube use the 4 then go to the 4-R

  • Beef

Posted November 28, 2004 - 06:30 PM


I agree with what RAD said, but in addition, you need to get the cylinder honed. You may not need to bore it out, but honing roughs up the surface of the cylinder, which allows the rings to be slightly worn down, and eventually (fairly quickly) get "seated."

If you don't hone the cylinder, the rings will never seat properly, and you will never take full advantage of that high comp. piston.

I'm kinda picky about how I break in an engine. Make sure you do a lot of accelleration and decelleration WITHOUT USING THE BRAKES. This helps blow/suck any metal dust out of the cylinder from the seating process, rather than letting it accumulate on the rings. Since your bottom end is already broken in, I'd say ride it like you stole it, and one ride is probably enough. On a brand new engine, I like to work up from about half throttle on the first ride, to WFO on the third ride, with conventional oil changes and new filter after each ride...then I switch to full synthetic.

Good luck!

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