Will i be able to tell if my YZ125 is running lean?

Hi everyone!

 

Two questions from me, excuse me if im blabbering in between the questions.

 

I am new to dirtbikes, I have only ridden an XR125L before, which is in no way similar to the YZ i just bought. My twostroke experience is limited to an old honda moped, which was restricted to death aswell.

 

The YZ125 I bought is a -99, a new piston has been put in, bearings and all that checked, however, as I am the worrying kind I need to know that it's not running lean, which according to the forums means certain death in a near future.

 

It runs great, had to adjust the idle mixture screw by about half a turn(inwards, richer) to get the throttle snappy, but let's imagine a scenario where it runs a tad lean, not enough to really notice, especially for me who doesn't have any previous experience from 125's at all. Would this be enough to seize the engine in a near future? 

 

If i roll slowly in 2nd gear, say 5-6 mph, and go WOT, it bogs completely until i lighten the throttle a little bit, if i roll on a little more careful and get some revs on the engine before WOT it pulls like a beast. From what I've read im getting mixed signals, some say its completely normal, and in other threads people are screaming lean. We're talking from a little bit above idle  to wot, in gear. Is it normal for it to bog in that case?

 

This might be stupid questions, but i just wanted some direction before starting to mess with jets, possibly for no reason. :rolleyes:

 

Thanks beforehand, Axel

Do a plug chop at the rpm you think it's lean.

If it's lean, it drops in power and bogs.

If it's rich it drops in power and surges/blubbers/pulses.

 

A 125's power band will not start at idle, period.

You have to roll the throttle till you get to the start of the powerband rpms, then you can go wot.

 

 

A 125's power band will not start at idle, period.

You have to roll the throttle till you get to the start of the powerband rpms, then you can go wot.

 

Thanks for the answer, what i suspected.  :applause:

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