All Things Moto! Web Forums

Go Back   All Things Moto! Web Forums > Dirt Bike - ATV - Suspension Forums > 2-Stroke Dirt Bike Forums

     
Reply
 
LinkBack Thread Tools
  #1  
Old 04-19-2010, 01:46 PM
Intermediate Class
 
Join Date: Mar 2010
Last Online: 05-18-2011 12:15 PM
Location: Macon, Georgia
Posts: 235
Default How often do you rebuild your 2 stroke?

Im kinda new to this sport, but I've pretty much fallen in love with riding. I think I've been out practicing on the bike at least 5 days a week the last two weeks since I got my bike running. As you can imagine the hours are clocking up on that rebuild pretty quickly. Eric Gorr says the 125 two strokes need new bottom ends every 80 hours. I think I'll go through 80 hours within the next year or two!

But I can deal with that, whatever.

But my service manual says i need to replace the piston every 7.5 hours. Do you guys really replace these things taht often? I will stretch that out to a few months probably just because Im learning to ride and I just dont have the guts to hold on and ride the pipe very often so it probably doesnt get beaten as much as some of the race bikes do, but still.

So I wonder... how often are you guys rebuilding your top ends?

Im curious about the bottom ends too. I dont think I'll just split the case at 80 hours and replace the crank, but its kind of sobering to think the week I spent learning to rebuild the bottom end may only be good for a year or two.

Just wondering what the real world intervals are... for us regular guys.
Reply With Quote
  #2  
Old 04-19-2010, 02:26 PM
farfromhome63's Avatar
Intermediate Class
 
Join Date: Jun 2008
Last Online: 04-14-2014 07:21 PM
Location: Morongo Valley, California
Posts: 362
Moto

you need a hour meter to accurately guage your riding time. I have a 250 2stroke and I religously keep the air filter clean and keep good oil and fuel. I make sure my jetting is right . I go without getting nervous 40-60 hours on a piston. 80 hours is pushin it.. now rods I usually check when I do the piston. the manual should state the range or tolerance.
In my case it lasted 10 years before blowing the lower bearing up! thats a long time. now if your not riding hard I say go 6 mo before piston replacement. and as long as the rod is inspected every time you change the piston I dont see what could keep you from using it for 2-5 years. air cleaner maint is the biggest culprit then jetting next is what causes failures. the piston skirt usually breaks and that takes the rest of the engine with it.. good luck have fun and be safe!
Reply With Quote
  #3  
Old 04-19-2010, 05:13 PM
KKXR400R's Avatar
ATM! Pro Class
 
Join Date: Dec 2003
Last Online: 03-18-2014 01:14 AM
Location: Thousand Palms, CA
Posts: 2,543
Default

The wife's CR gets a piston after 80-90 hours and a re-ring around 40-50 hours. The KTM seems to last a little longer. I pushed 114 hours and 21 races on a stock piston/rings. When I pulled the top end apart the rings, piston and cylinder were still in spec and cross hatches were still visible. I tear the low ends apart every other season. Just to make things easier I have adopted the same schedule as the CR.

Buy yourself a compression tester and an hour meter. These are great indicators of the life of your top end. Keep records/dates of the numbers your getting, the maintenance you do to the bikes (bearings, cable cleaning etc) and settings (suspension, jetting etc).

Hope this helps.

-Kevin-
Reply With Quote
  #4  
Old 05-14-2010, 06:41 PM
Beginner Class
 
Join Date: Jul 2009
Last Online: 09-26-2010 12:37 AM
Location: gardner
Posts: 26
Default

i usually wait till it looses power or makes noises to replace major engine parts. But it also depends on how you ride, my father has a 78 rm 100 all original except for the clutch and its still being ridden and starts up 2nd kick
Reply With Quote
  #5  
Old 05-14-2010, 07:37 PM
Intermediate Class
 
Join Date: Jan 2010
Last Online: 07-02-2013 12:35 PM
Location: Omaha, Nebraska
Posts: 110
Default

I do rings at every 15-20 and a new topend about every 50-60.
I kind of over do it personally. I like that fresh topend feel.
Otherwise, I have probably 100 hours on the bottom . . . I just change the oil every other ride and filter every ride. Not a fan of splitting cases. Crap I have been sitting on a new crank for two years . . . no real play / vibes from the crank
I get in the habit of getting extra base gaskets. You can always take a look at the piston / ring / cylinder for 4-5 bucks. Rings are reasonable also.
Reply With Quote
  #6  
Old 06-09-2010, 05:13 AM
Beginner Class
 
Join Date: Mar 2010
Last Online: 06-16-2010 08:29 AM
Location: kinross
Posts: 26
Default

i just ride my bikes till they stop, in my opinion theres no point replacing something unless it has to be done, or its just a waste of money
Reply With Quote
  #7  
Old 06-09-2010, 06:27 AM
Intermediate Class
 
Join Date: Sep 2003
Last Online: 04-08-2013 05:48 PM
Location: McDonough Georgia
Posts: 391
Default

hundreds on my ktm, 80-100 on my japanese mx bikes
Reply With Quote
Sponsored Ads
  #8  
Old 08-01-2010, 03:58 AM
Novice Class
 
Join Date: Aug 2010
Last Online: 10-08-2010 11:08 PM
Location: new zealand
Posts: 90
Default

i keep the air filters and make sure the mixtures always correct to keep the top end in its best condition. then i just run it till its outta compression.

ive gotten over 100 hours on my cr, then it needed a new ring job
Reply With Quote
  #9  
Old 08-09-2010, 09:52 PM
skos's Avatar
Beginner Class
 
Join Date: Aug 2010
Last Online: 08-27-2012 08:26 PM
Location: Texas
Posts: 34
Default

Quote:
Originally Posted by rodogg View Post
i just ride my bikes till they stop, in my opinion theres no point replacing something unless it has to be done, or its just a waste of money
Agreed. My 98 YZ I bought for 1200 bucks 5 years ago. Rode it hard about 20 times a year sometime for 6hr at a time. I take real good care of it. When something breaks, I completly fix it (if I have the money).
Reply With Quote
  #10  
Old 08-09-2010, 10:44 PM
ATM! Addict
 
Join Date: Oct 2003
Last Online: 04-14-2014 08:07 AM
Location: alaska
Posts: 10,344
Default

The kind of bike owners I won't ride with if we are getting out of sight of the pickup, just responded lol
Reply With Quote
  #11  
Old 08-12-2010, 02:58 PM
Welcome To ATM
 
Join Date: Aug 2010
Last Online: 06-19-2012 06:07 AM
Location: Denmark
Posts: 1
Default Yamaha YZ 125 2008 Bottom end rebuild interval

Have just purchased a used bike for the next season, it have 125 hours on the hourmeter, do it need rebuild of the bottom end ?
Reply With Quote
  #12  
Old 08-13-2010, 12:43 AM
ATM! Addict
 
Join Date: Oct 2003
Last Online: 04-14-2014 08:07 AM
Location: alaska
Posts: 10,344
Default

skos thinks you should wait for it to break.
Reply With Quote
Reply

  All Things Moto! Web Forums > Dirt Bike - ATV - Suspension Forums > 2-Stroke Dirt Bike Forums


Bookmarks

Thread Tools


Similar Threads for: How often do you rebuild your 2 stroke?
Thread Thread Starter Forum Replies Last Post
form on 2 stroke vs 4 stroke trail bike mxmama393 Dirt Bike Riding Tips 39 03-20-2010 12:44 PM
03 YZ 250 2 stroke rebuild ralphy_69er 2-Stroke Dirt Bikes - Yamaha 3 07-09-2009 07:23 AM
4 stroke rebuild motocrossjake12 4-Stroke Dirt Bike Bike Forums 3 06-13-2007 09:21 PM
2 stroke engine rebuild question Blaster2678 2-Stroke Dirt Bike Forums 8 11-27-2004 10:14 PM
4 Stroke Top-End Rebuild Frequency DCox 4-Stroke Dirt Bike Bike Forums 21 01-24-2004 07:45 AM


All times are GMT -6. The time now is 04:14 AM.

Portal Forums Photo Gallery Popular Tags RSS Feeds

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright ©2002-2014, JDub Consulting, Inc. All Right Reserved.