You put the slide in the wrong way around, if you look closely you will see markings on the slide, the one side have a small V cut on it where the throttle stop slides in and on the other side a small slit that guides the slide, it happens to me all the time, luckily it is an easy fix.
1983 Honda ATC250R
1983 Honda ATC200E BIG RED (sold)
1984 Honda ATC200E BIG RED
1984 Honda ATC200X (sold)
1985 Honda ATC70 x 2
1985 Honda ATC250ES BIG RED
1988 Honda ATC250ES BIG RED
1995 Honda Frankentrike 50cc 2-stroke
2001 Honda TRX90
2004 Honda TRX300EX (sold)
2008 Honda TRX250TM
1976 Suzuki RV90M (sold)
1967 Vespa Primavera 125
1958 Massey Ferguson 35