alright i know its been done a hundred times and have read them all but i cant seem to find anyone with similar mods to me... seems like everyone is running with a cam mod and no lid. so ok i have a 2008 yfz with an LRD pro 4 slip on and a uni air filter running in the Eau Claire Wisconsin area. so umm here goes the million dollar question and dont tell me to go read cuz i have been reading every post on here to find what i should run at but i am running a 155 main and a 42 pilot changed the needle and dont remember what clip it is on but i cant seem to break 60 mph. it cuts out horribly on the top end and still has a good amount of bog and i have played with the jetting and cannot seem to get it right. dont tell me what my problems may be please i just want to find someone who has theirs tuned with similar mods and find out their jettings and fuel screw. THANK YOU SO MUCH!! i would appreciate it more than you would know if i could get it running the way it is supposed to thanks.

with your top end falling on its face like that, your main is way low, i would bump it up a good bit, sorry i cant help with actual numbers.

155 main and a 42 pilot changed the needle


Mine isn't dynoed and I am in Upper Peninsula of Michigan. Mine is a 48 pilot and a 135 main on the fourth clip down. I am hitting about 65 with 18 in tires if I put 20's on I can get 90 and that is with 15 tooth front sprocket and two teeth more on the rear from stock.

Hey I am only 30 miles north of ya switch to a 135 main, Every one of my friends (and me ) run a 135 main. yfz450 and 450Rs