ETON Viper 90 - Excessive smoke from tailpipe

Hello,  Looking for some good advice!  I have 2 2004-2005 eton viper 90's. They smoke a lot when started and continue for 5-10 minutes (one more than the other). I do mean a lot of smoke for this little machine.  Once they get going they become normal smokers.  I have thought this was due to the fact that the oil drips into the carb from the oil injection when they sit for a while.  When I start it up it smokes until all that excess oil is gone and then they are normal.  During a rebuild of my carb last week I dropped the bowl and the whole thing was full of oil with a splash of gas.
Since they lean out when they are running I assume the carb is adjusted correctly.  
My next inclination is remove the auto oil injection and go premix.  The things run nice I would just like to lighten up the smoke a bit.  
What is the best way to remove oil injection and will I have to re-jet?  Does re-jet mean just order another jet to screw into the bottom of the carb when the bowl is off and that is it?  What size jet would I need.
Thanks  

I have one also and it runs fine, but did smoke excessively at one point to where it would start hard and smoke to the point of running rough.  I thought I had injector probems, took it to my mechanic who immediately took the spark arrestor out of the tailpipe.  one screw and a pair of needlenose pliers--problem solved.. it runs like fantastic ever since and probably has over 600 miles on it.  My issue right noe is that I keep blowing the main fuse, I think at certain times when my son shifts it.  I need to check cnnections etc.  

Hi Jayman99,  Sorry for the late reply I had a road trip to Bristol.  I have the spark arrestor out of one of the eton's.  The other eton with the issue does not have a screw or a way to remove the spark arrestor.  I bought them both new at the same time but I think one is an 05 and the other without the screw is an 04.  In the meantime I have ordered a single pull throttle cable and an oil block off plate so that I can get rid of the oil injection.  I always thought it ran too rich and now with the excessive smoke I think the unit might be malfunctioning and instead of fixing it I would prefer to remove it from the equation.  I have been getting pretty brave with some of my recent undertakings as an atv mechanic but it does offer a great deal of satisfaction when I manage to do something right!  

I HAVE FOUND AMSOIL REDUCES A LOT OF SMOKE. \I HAVE 4 2 STROKE MACHINES AND AND HAD GREAT SUCCSESS WITH AMS OIL.  

Hey WAMPLER,
What ratio do you use on the AMSOIL?  I successfully removed the oil injection on the ETON and went with a cheap 32:1 Spectra Blue oil mix.  I have heard AMSOIL is superior.  They have a Saber Professional at 100:1 and the Dominator 50:1.  I would think 100:1 would be best to reduce smoke but I want to make sure the engine is protected.
Thanks