Im having problems fouling up my rear plug on my twin carb SJ. it's a real pain and I've been trying to lean it off with the Low speed needle adjuster but no luck... I'm guessing I will need to replace the low speed jet or the spring but not sure what to do first. Not to sure what I'm doing with pop off pressures and all that. I'm also assuming it a low speed problem because when I open the throttle it will eventually clean it's self up the run sweet until it fouls with low speed riding. I want to get it sweet before I go putting higher compression domes in. Any input would be great.