Well I tried the Pilot jet change...

[lakota]

I am having problems with the idle and excess spooge on my '90 Rm125 so I took the advice of many and changed the 55 pilot to a 60.

Yuck. It bogs terribly off idle. Takes forever to bring the revs up. I have the air screw set at 2 turns out. Tried it at other settings, but 2 turns seemed to run the best (still bogging badly ). It ran much better with the stock 55 inside and air set at 1.5 turns out.

Any suggestions? If I try the 50 that I have, how will I know if it's right and not too lean?

 

[darringer]

You need to go SMALLER on the pilot, not larger. A 50 would have been a better choice to lean out the idle. It would be almost impossible to do any harm with too lean a pilot, since there is very little load at idle.

 

[David Trustrum]

Quite. Yes the airscrew is richer when you turn it in so not knowing what was said before seems like you need to go smaller (which may help the spooge problem).

Only issue is the “can’t hurt it with pilot jet” (don’t let me stop you trying a smaller one) but consider this, quite often when a road race bike will seize its on closed throttle. Wide opennnnnnnnn long time. CLOSE. Burrrr nuck!

Probably not such a prob on a dirt bike unless used in wide open spaces.

Try a smaller one & adjust the airscrew blipping in neutral from closed throttle until it doesn’t hesitate (lean) or bog (rich). May need to change jet to get it into those extremes. Yes both these feel a bit the same, but 'hesitate' is more bi*chy.

Then adjust richer & try it under load & you should be right.