OzVMX Forum

Marque Remarks => Yamaha => Topic started by: twj1958 on July 11, 2008, 11:55:45 am

Title: 79 yz125f ignition timing
Post by: twj1958 on July 11, 2008, 11:55:45 am
Can anyone help, my 79 yz125f is pinging a bit & has very little low down power (it has new rings) if i adjust the timing will it help? and is there an easy way?
Thanks Terry
Title: Re: 79 yz125f ignition timing
Post by: Nathan S on July 11, 2008, 12:38:23 pm
Broadly speaking, more advance gives more bottom end, but also more pinging - so it sounds like you're stuck between a rock and a hard place.

However, given that the 125F is a peaky bitch of a thing to start with, maybe you're simply too advanced.
Is the jetting/plug/etc right?

Timing should be 1.2mm BTDC - and don't trust the marks on the stator coil and rotor, as they rarely actually line up when the ignition is firing.
What I have done, is find 1.2mm BTDC, and mark the stator and rotor at that point. Then use a timing light to set the ignition to that mark (at a low idle! If you rev the bike, you should be able to see the timing become more advanced).

Oh, and apparently an E barrel helps make the bike rideable. You also need an E pipe to match the barrel.



Title: Re: 79 yz125f ignition timing
Post by: twj1958 on July 11, 2008, 12:56:49 pm
Thanks Nathan, I thought as much & yeah It is very peaky!