ok my freind has a 98 xc 600. (136'' 1.25'') twin piped, slp heads, reeds, clutched, geared... and it was running great last season. then he bougt a booste bottle and put it on and now it runs like crap. and he asked me to help tune it, and i thought no prob... then i dug into the carbs and soon realized theres a big diff between them and the round slides i got... heres were where at, we adjust the carbs acording to slp instructions (its not a slp booste bottle though) and it will either not idle or coninue to rev up untill we shut it off (and it will rev high like 5-6000 with out touching the gas) and thats with the sldes all the way down, and it don't matter where the screws are at

Its your air screws that you need to adjust. You are lean on the bottom end thats why it revs up and wont come down another words too much air so you need to adjust them. If you need more info let me know i can explain to you how to do it and how to know if you need to bump up a jet size when you run out of air screw adjustment!

so we don't need to touch the slide adjust ment? we started out with only half a tunr out n the air scews and it still did it

a boost bottle will cost 4 hp on the dyno with almost all twin pipes. they just dont work together. mike

You might want to check your carb adapters for cracks (ether trick). The weight of the boost bottle flopping around cracked a bunch of them if memory serves me right.