mpcshaggy

Member
May 7, 2013
3
0
New to the site looking for a little help.My 1988 cr 125 is fouling plugs like crazy.I recently bought it and was told it has rebuilt topend.I've changed the reeds,leaned fuel to 40-1,completely cleaned the carb,and air filter.I have done a compression test,after about 15 kicks it stopped at 160 psi,it then held that for close to 10 minutes.It will run great for about an hour then just stop running.I'll put a new plug in,it will start right up and run great for another hour or so.It will go thru 3-4 plugs in a good afternoon,I don't know
what else to do but plant flowers around my new yard ornament,please someone help.
 

ojasia

Member
Mar 13, 2013
52
0
Get a service manual and read. Check out the Stock needle position and jet setting's. A carb that old no telling how many times it has been messed with. Try going back to stock setting's and go from there.
 

kxracer177

Member
May 7, 2013
3
0
agree, get a service manual, and go through your settings, (jets, sizes, and condition ) with a fine tooth comb.
Did your 125 have a power valve or was it case reed?
if its running fine initially and then after a while dies, then I would also be checking the electrical.
Check your primary and secondary side of your coil, just to be sure.. :yikes:
 

RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
7,045
208
North East USA
You could also have a leaky crank seal on the right side that lets tranny oil get sucked into the cylinder. A leak down test will show it
 

2strokerfun

Member
May 19, 2006
1,500
1
As old as your bike is, if you still have stock carb, it could be a worn needle jet, needle, or slide (or any combination thereof). Frustrating to diagnose, but fairly easy to fix. I chased that problem for a year on my old bike (rebuilt engine, changed seals twice, changed jets and needle a couple dozen times) and finally just bought a new carb from Sudco.
 

mpcshaggy

Member
May 7, 2013
3
0
thanks,i'm getting pretty frustrated with this bike.I recently rebuilt the top end,got everything back together,and now i can't get the bike to start.I'm at a loss ,everything appears to be clean,just wont start,plenty of fire.Do you think it could be the reeds?
 
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