Posts: 64
Joined: 2/21/2013
Location: Hillsborough, NJ USA
My son's Yz125 won't rev out and breaks up at 3/4 to Full throttle. This unfortunately happened at the all-star race at high point. It ran well without the humidity, Lowered main to 400 and raised clip to top on needle. It got better but still wouldn't go. Any help would be appreciated.
Posts: 5833
Joined: 1/31/2018
Location: Mansfield, OH USA
Im sure its jetting related because of the humidity you mentioned, but i have seen bikes not rev out due to a bad plug or incorrect plug gap.
Posts: 7424
Joined: 10/31/2013
Location: PA, USA
Posts: 612
Joined: 4/1/2008
Location: Kamloops, CAN
Posts: 64
Joined: 2/21/2013
Location: Hillsborough, NJ USA
Edited Date/Time:
Bob,
Builds and sounds crisp until I put it full throttle, then it breaks up.
Chill,
Gonna meter all ignition now.
Thank You
Posts: 64
Joined: 2/21/2013
Location: Hillsborough, NJ USA
Went through ignition specs. Only out of spec reading is primary ignition coil. Spec is .24 -.36 OHMS. Mine is reading .5 ohms. What do you think?
Posts: 5833
Joined: 1/31/2018
Location: Mansfield, OH USA
Sounds like you got a bad coil. Too much resistence for a supplied voltge will result in a weak or no spark
Posts: 612
Joined: 4/1/2008
Location: Kamloops, CAN
Had the coil do the same thing on a KTM105SX. Hopefully you have buddy with a YZ125 so you can try it b4 you buy one.
Posts: 64
Joined: 2/21/2013
Location: Hillsborough, NJ USA
