Break-in after rebuild

YZrider111

Member

Dec 5, 2002

14

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• Dec 10, 2002

• #1

I just rebuilt the top and bottom end on my old yz125. Does anyone know any break-in tips or procedures?

 

I

IrishEKU

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Apr 21, 2002

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• Dec 10, 2002

• #2

The one that seems to work the best depending on what type of piston you used (For a Wiseco) is to start and warm up. Shut down and cool. Repeat about four(?) times and then ride it. During this process you can check for any exaust or water leaks. I don't know what year your YZ is but if it is as old as mine, you will notice oil around the PV cover befor too long if you didn't clean and replace the o-ring.


Whoops, almost forgot, since you did the bottom end did you soak the lower bering with some mix? If not pull the plug and cycle the engine a number of times to get some mix in there to lube the bering.
Good Luck,

 

Last edited: Dec 10, 2002

V

viking20

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Aug 11, 2002

428

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• Dec 10, 2002

• #3

I usually do it this way too,no matter what piston was put in during the rebuild.
Keep a spare plug ready if it fouls up when idling the first couple of warm ups!
Then ride a few easy 10 min.stints with a total cool-down in between,and then -ENJOY!Change the gearbox oil after an hour or so....

 

R

ryanfoley

Member

Sep 17, 2002

129

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• Dec 11, 2002

• #4

why do you have to change the tranny oil?

 

T

The^^Rock

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Feb 18, 2002

174

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• Dec 12, 2002

• #5

Because he has a fresh bottom end :)

 

F

Fark

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Aug 12, 2002

438

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• Dec 13, 2002

• #6

?? The crank has what to do with the gearbox?

There is no oil pump or oil in the crankcase.

Though I suppose condensation could form in the gearbox with the warm up/cool downs.

 

I

IrishEKU

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Apr 21, 2002

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• Dec 14, 2002

• #7

Originally posted by Fark
?? The crank has what to do with the gearbox?

Click to expand...

:think: It could have something to do with making that rear tire turn a bit but I'm not too sure.

 

V

viking20

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Aug 11, 2002

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• Dec 14, 2002

• #8

Well,if you split the cases to get to the crank,youre opening up the gearbox as well.I would strongly advice you to check all the gears while youre in there!
Changing the oil just make it easier to get rid of any debris,before it does any harm,IMO.If its a bike with alu plates,youre better off changing the oil every 2-3 hours anyway.Some people change the tranny oil every ride!My local dealer just rebuilt a 02-cr 125,the rider is a known clutch abuser,and he didnt bother to change oil either.It needed all the gears changed,both clutch hubs and plates.One engine block had to be changed too,the bearings had spun in the case!

 

YZrider111

Member

Dec 5, 2002

14

0

• Dec 14, 2002

• Thread starter
• #9

Wow that sounds nasty. We sent our motor in to a guy locally and hes doing it all for us. I will ask him about the gears and the clutch. So should i change the oil after uts totally broken in?

 

V

viking20

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Aug 11, 2002

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• Dec 14, 2002

• #10

Maybe some people will disagree,but I feel its most important to change the oil often,instead of running an expensive gear oil(in a 2-stroke!)I use simple 10-40 motor oil and change it every 2-3 hours on my sons cr 125.The Hondas use aluminium clutch plates,these contaminate the oil more than steel plates.
So,I would change the tranny oil after the first hour or so,after a rebuild.After that,every 2-3 hours.

 

F

Fark

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Aug 12, 2002

438

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• Dec 15, 2002

• #11

Originally posted by IrishEKU
:think: It could have something to do with making that rear tire turn a bit but I'm not too sure.

Click to expand...

Irish, I've run into a few people under the impression that the 10w40 used in gearboxes also lubes the bottom end. True 4 strokes, but not on 2 strokes.

 

J

jet373

Member

Apr 2, 2002

18

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• Dec 20, 2002

• #12

man i listen to peeps and i just dont get it sometimes .......... it not like your breaking a car motor with babbit bearings and ....all you breaking in is the piston and rings ...... there is no breaking in to roller bearing .......i built at least 100 engines in my time ..... i run to get them hot ..... cool ....... then race