OzVMX Forum

Marque Remarks => Yamaha => Topic started by: jimg1au on March 05, 2011, 03:55:11 pm

Title: Yamaha zy125x ignition timing
Post by: jimg1au on March 05, 2011, 03:55:11 pm

just rebuilt my engine and am having trouble getting it to fire.
the manual states 1.2mm btdc.line up marks on stator.there are 3 marks on the stator 1 little mark larger mark and then small one again.
lined up the centre large mark with the 1 on the rotor it fires sumtimes but wont run even pushing fires but wont run
has new stator and bike ran well before rebuild.has good spark
has fuel and even wont fire with arostart down plug hole
the only thing i have changed is the conrod big end and gearbox as i got a near new gearbox fro a yz100 same as my 125x
have put 1 larger idle jet as it locked up a few times at the end of the straight at griffith d/t nats.it started straight away after stoping.
any ideas
jim

Title: Re: Yamaha zy125x ignition timing
Post by: vandy010 on March 05, 2011, 04:16:32 pm

1.2 btdc sounds right.
silly things to check...
is the plug fouled?
and/or is the needle-jet inserted at the correct location {silly, but i've been caught out with this one before and the bike would not start}
i'm not too familiar with the stator/coil set up on these motors but is it possible the coils are bolted to the stator 180 degrees out?
thats all given the spark is good.

Title: Re: Yamaha zy125x ignition timing
Post by: jimg1au on March 05, 2011, 05:46:10 pm

thanks for the reply
tryed 2 new plugs same result
5 times spray with arostart but runs like plug is fouled but its new
stator marks on top as per dia in manual
will recheck carby tomorrow
jim

Title: Re: Yamaha zy125x ignition timing
Post by: Iain Cameron on March 05, 2011, 06:23:05 pm

jimg1au I had the same problem ended up being the pipe needed a burn out