Join Date: Jan 2006
Location: Eastern Ontario, Canada, Earth, Solar System.
When you remove the air filter, you can look down into the air intake manifold. You'll notice 4 valves (round silver discs). 2 are near the top of each intake and 2 at the very bottom of each intake funnel.
The secondaries are the 2 near the top. They are secondary butterfly valves that act as restrictor plates and help the bike meet Emissions standards.
By removing the little screws that hold them in place (and be careful not to drop them into the intake)!!!, you can then remove them. Your airflow into the funnels will increase by 30% (dyno'ed) and more air=more power. Also, it'll mean crisper throttle response and much much much less farting/stalling, although it'll do it once in a blue moon, like any V-twin.
Never Argue with an idiot, first he'll bring you down to his level, then he'll beat you with experience...
1986 FZX750R Fazer-Should've never sold it!
1986 BMW K75-Old smoker! Good bike. Sold.
2003 DL 1000 Bumble Bee, farkled! Sold.
2006 Honda Goldwing Navi AL.