06 yz125 big bore 144

jmpatt79
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jmpatt79
Edited Date/Time 1/20/2015 9:00pm
motor pulls hard as hell all the time never a bog or anything , runs great never any hesitation but sometimes when landing off jumps or after rev in the air bike makes a pop like noise !!!!!only happens every once in a while not everytime !!!any suggestions ?
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slipdog
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slipdog 12/5/2014 7:29am
12/5/2014 7:29am
Probably a lean pop, look at the plug to see if it is on the light brown to greyish/white side Try a larger main jet. 2 strokes tend to pop at the rev limiter when too lean.
Jakes Dad
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Jakes Dad 12/5/2014 3:53pm
12/5/2014 3:53pm
Adjust float height a hair, it can cause a lean condition also. Usually from my little knucklehead emptying the bowl by revving in the air. How I found out and little adjustment helped a lot. That and threatening his little ass helped too! LOL
Jakes Dad
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Jakes Dad 12/6/2014 8:48am
12/6/2014 8:48am
Yep they all have that same guilty look! Wink

The Shop

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yamahuh
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yamahuh 12/7/2014 12:20pm
12/7/2014 12:20pm
JMPatt,
Who did the 144 work for you? Feel free to give any recommendations as I'm considering that mod as well.
Thanks
jmpatt79
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jmpatt79 12/7/2014 5:59pm
12/7/2014 5:59pm
yamahuh wrote:
JMPatt,
Who did the 144 work for you? Feel free to give any recommendations as I'm considering that mod as well.
Thanks
it locked up today after doing about seven laps on a local MX track , gonna check it out this week and see what happened ......
jmpatt79
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jmpatt79 12/9/2014 6:07pm
12/9/2014 6:07pm
i will this weekend , i will post up some pics of damage then !
jmpatt79
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jmpatt79 1/2/2015 5:31pm
1/2/2015 5:31pm
left side crank bearing locked up , ive been hearing do not use hot rod crank bearings due to premature failure , thats what this is so i was wondering does anyone have any suggestions as to what crank bearings to use ?

j368
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j368 1/2/2015 6:05pm
1/2/2015 6:05pm
OEM Yamaha
jmpatt79
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jmpatt79 1/2/2015 7:48pm
1/2/2015 7:48pm
after carefully examining everything i believe that the crank seal was sucking in a little air at the bearing area .... right bearing looks well lubricated but left bearing looks dried out and turning into dust , just my thoughts
holverson34
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holverson34 1/2/2015 8:09pm
1/2/2015 8:09pm
jmpatt79 wrote:
motor pulls hard as hell all the time never a bog or anything , runs great never any hesitation but sometimes when landing off jumps or...
motor pulls hard as hell all the time never a bog or anything , runs great never any hesitation but sometimes when landing off jumps or after rev in the air bike makes a pop like noise !!!!!only happens every once in a while not everytime !!!any suggestions ?
Sell it
jmpatt79
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jmpatt79 1/2/2015 8:14pm
1/2/2015 8:14pm
jmpatt79 wrote:
motor pulls hard as hell all the time never a bog or anything , runs great never any hesitation but sometimes when landing off jumps or...
motor pulls hard as hell all the time never a bog or anything , runs great never any hesitation but sometimes when landing off jumps or after rev in the air bike makes a pop like noise !!!!!only happens every once in a while not everytime !!!any suggestions ?
holverson34 wrote:
Sell it
hell no ....... this thing is a beast and runs like a scalded dog !!!! i'm putting a new crank and bearings and new top end and see what happens !!!!!
yamahuh
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yamahuh 1/3/2015 4:40am
1/3/2015 4:40am
You have already changed out the shift stopper right?
BobPA
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BobPA 1/3/2015 8:06am
1/3/2015 8:06am
Jakes Dad wrote:
Adjust float height a hair, it can cause a lean condition also. Usually from my little knucklehead emptying the bowl by revving in the air. How...
Adjust float height a hair, it can cause a lean condition also. Usually from my little knucklehead emptying the bowl by revving in the air. How I found out and little adjustment helped a lot. That and threatening his little ass helped too! LOL
Not possible for someone to perky the bowl in the air....better rethink that theory.
Jakes Dad
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Jakes Dad 1/3/2015 11:46am
1/3/2015 11:46am
Not "perky the bowl" low float height causes a lean condition. That's my "theory"..... check it.
Falcon
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Falcon 1/3/2015 10:42pm
1/3/2015 10:42pm
I second the vote for OEM on the crank bearings.

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jmpatt79
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jmpatt79 1/3/2015 11:18pm
1/3/2015 11:18pm
plug looked good not on the lean side , can i get a reason for hot rodz bearings bad from some previous users
chillrich
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chillrich 1/4/2015 8:55am
1/4/2015 8:55am
We've used HotRods main bearings in 85SX without failure which I would consider to be much more brutal conditions than a 144.
jmpatt79
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jmpatt79 1/20/2015 6:11pm
1/20/2015 6:11pm
after speaking with a local engine builder he said to use NTN bearings so thats what i did 06 yz125 crank bearing part number is NTN 62/22LL you can get them at your local bearing house or use A&W bearing in Dallas
garagedog
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garagedog 1/20/2015 8:59pm
1/20/2015 8:59pm Edited Date/Time 1/23/2015 5:28pm
Just a theory here.... if the float height is low.... and you jump into the air.... the gas will slosh up to the top of the float chamber as your bike starts to drop down.... so this leave the bottom of the carb full of mostly air (where your main jet is) causing a lean pop.

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