I posted this in another subject, but then I saw this thread and thought it may be more suitable. My son's new YZ85 is puking or spooging out the exhaust. I know some do it to some extent, but it is real bad. Is this from jetting, oil mixture, or what?
Yes, it does smoke. It's is brand new and not even broken it yet, so I have been leary of jetting too lean. I did go down one on pilot though and seemed to help with fouling.
Fuel mixture: 32:1
Altitude: 800 ft.
Tempaerature: 90 f
Jetting: Main = 138 (which is stock)
Pilot = 42 (stock is 45)
I am new to 2 strokes so any help is greatly appreciated.
That's pretty normal mostly all bikes come from the factory jetted rich to prevent engine failure. After break-in I would start leaning out the jetting, pilot/needle/main untill it stop spooging and throttle response is crisp.
My son's rm 125 came so rich that it would barely even run. I had to drop my pilot jet on the yz 250 two sizes. Once you start closing in on the correct jetting the spooge will diminish, just go one jet size at a time. I think most spooge will come from your needle and pilot.
You can search Rich's and Eric's forums for alot ot techincal info related to spooge.
Getting the main correct is easy .. The needle and pilot as mentioned is the problem. If you get the pilot too lean the idle will race/run on. Too lean on needle and you will get a big bog. I usually take it sort of lean and then work up to rich especially in the summer when it is hot.