My friend just bought a 98' 300ex today and it has a K+N filter and a whitebros e-series pro mge pipe , My question is what should it be jetted at , right now it has a 130 main and it runs Like $h!t !! What jet should be in there ? also where should the neadle clip be?? please HELP ME i told him i would fix it for him and NOW I HAVE TO DO THIS TOMOROW MORN ! HELLLPPP !!!!!!!!!

 

IT all depends on your elevation. I had a 130 in mine and it was alittle rich, so i dropped to a 125 and raised the needle up one notch from stock. MUCH BETTER. What does his plug look Like? Is his exhaust pipe endcap turning black?

 

I wanted to read the plug but The guy who owned it before did alot of road riding in the winter so the plug cap was corroded on the plug and wont come off. I think it is running lean but I can't be sure , It blows out blue smoke like a 2 stroke or even worse. The endcap is completely BLACK i will try raising it up 1 notch and adjusting the fuel mixture screw. ANY MORE TIP WOULD BE VERY HELPFUL !!!!!!!!!

 

alot of smoke means its running rich. you need to put in a clean plug or a new one, start it up, open it full throttle, hold it and hit the kill switch. Then check your plug. Your air/fuel mix will be between 2and a half and 3 turns out.