How many hours before I need to replace main bearing on a 125?

Related:
Create New Tag

10/4/2018 8:10 AM

Currently my 18 YZ125 has about 32 hours from new on it. Was wondering how many hours before I should replace the main & crank bearings? Am I on the limit or can I go longer? I'm not particularly quick so it's not getting ridden really hard.

|

10/4/2018 9:03 AM

Just check your bearings when you do top ends. You can get 100+ hours out of a 125 bottom end. Its the top end on those that need constant attention.

|

10/4/2018 9:15 AM

kb228 wrote:

Just check your bearings when you do top ends. You can get 100+ hours out of a 125 bottom end. Its the top end on those that ...more

So I'm well within then, I did think it would be a lot of hours before it needed changing but wanted to know when people did theirs.

|

10/4/2018 12:55 PM

Depends on how hard you ride it as well. The guy who is on/off the throttle constantly or cruising through trails can probably get a few hours out of a bottom end. The guy who rides track and revs it out 4 times a week will need constsnt rebuilds...

|

10/4/2018 10:46 PM

I did my KTM 125 bottom end at 90ish because I broke a tranny gear. Everyone told me that bottom ends should at least go 100 depending on the rider and maintance performed.

|

10/5/2018 10:26 PM

Back when we were racing 125's we would do a bottom end every 4th piston. That put it around 80-100 hours

|

10/7/2018 7:08 AM

All good advice from everyone..... You can grab the fly wheel & push/pull move back & forth, any movement, in/out, up / down is play in bearings.

|

10/7/2018 8:18 AM

I cant speak for any other brand except for Yamaha. We have several 125s, 134, 144... We have no problem getting 100+ hours on the factory crank / bearings. We have not found a aftermarket crank bearing that lasts longer then 20 hours. Im sure there are great ones out there but we haven't found em.

Top end 20 hours
Lower end 100ish hours
Ethanol free fuel
Amsoil 40:1

|