Removing the "Garbage"

Need some sound advice from you experts out there. When I initially bought the bike, the vacuum hose from the air switch (between the coils) that goes to carb #1 & 4 via a tee was removed and the vacuum nipples plugged on carbs, but the air switch was still attached. The main breather hose was routed straight from the air switch to the crankcase breather cover, and airbox removed in favor of pods. I have now gone back to stock airbox, and have a question about the air switch system.

Right now I have the air switch valve assembly on my bike, together with the vacuum hose into 2 hoses that go to #1 and #4 carbs. Vacuum niples on #2 & #3 are plugged as I have a non-vacuum petcock.

I keep reading posts referring to this setup as "garbage" and not functional aside from polution control guidelines here in the U.S.

Question #1: Is it as simple as that, or will removing that "system" throw my mix off or result in re-jetting? Or have I misunderstood, and the "garbage" is only referring to the vacuum hoses to carbs #1 & #4?

Question #2: If removed, do I just install a hose between the two valve cover breather outlets, and plug-up the hose inlet in the airbox?

Question #3: Does the airbox bottom air filter tube (L-fitting at bottom of airbox) stay attached to the crankcase (breather cover), or do I plug that up as well?

Finally, will removing this system improve performance, or is removal considered just removing a useless system? I'm lost on this one, and would really appreciate any feedback!

Post edited by: Norseman, at: 2007/05/15 09:39

Norseman, I hesitate to answer this because it has been hashed over so many times before in the past but...

The emissions control stuff draws unburned hydrocarbons back into the exhaust runner to be burned and solids (like from engine blow-by) are routed into your air cleaner... The same system is used on more modern bikes... the system does a couple things...
1. makes epa happy
2. cause bike to backfire on deceleration
3. causes the under-tank area to be a clutter

If the system is removed, the effects are reversed some:
1. doesn't burn those unburned hydrocarbons
2. bike stops backfiring on deceleration
3. cleans up area under tank

The system consists of the vacuum hoses connected to 1 & 4 carbs. These hoses go to a tee which has another hose coming out that goes to the vacuum switch which opens your reed valves (in the valve cover).

To get rid of the system, remove the vacuum hoses, tee, switch, large hoses. Leave the L hose going from your crank vent into your airbox alone or route a hose off the crank vent over your swingarm if you don't want oil in your airbox (in the event you have engine blow-by). Either cap, connect with a common hose or fill with RTV the two large spigots atop your valve cover. Put caps on the vacuum ports on your 1 & 4 carbs. That is about it... There will be a hole in your airbox where the big tube went from the vacuum switch and you can plug it if you like or just leave it.

Thank you, WiredGeorge, for your response and once again taking time to provide guidance to a newbie. I did do a few searches before posting, but didn't find anything - probably used wrong search criteria.

Thanks again.

I need to write this up and put it on my website... the basic info is common to MANY bike makes and models. I first noticed the problem with a Kawasaki Vulcan I owned that backfired like crazy till the reed valves were capped off and the emission stuff removed. I have the SAME system on my 2001 Bandit 1200... it also causes backfiring although not an irritating amount. The main issue is that all the hoses sit atop your valve cover and make the bike twice as hard to work on.