What's an airbox lid?

[Guest]

Finally had the extra cash to replace my rusty exhaust and went with a Vance & Hines 4 in 1 that just arrived today. Yay!

Directions say to increase the main jet to a 120 - OK.

But it also says to remove the stock airbox lid. Huh?

What lid? The only thing on top of the airbox is that hose - am I supposed to remove that?

Z1, where I got the V&H, also suggested shimming the needle.

Everything on this bike is stock at the moment -

So I was planning on increasing the mains and seeing how the bike runs before I tried shimming the needle as well.

Is that a bad idea?

[tkent02]

On the 850 air box, to remove the lid won't work, as you would only be getting unfiltered air.

[oldgsfan]

So just go up on the mains and forget the deal about the lid? That's fine cause I still don't know what they mean by 'lid.'

[Steve]

Some bikes have a two (or more) piece air intake system. Starting at the carbs and going backward, there is the manifold that distributes the air to all the carbs, then a box that actually holds the filter. That sits in the frame where your battery is located. Access to the filter is by removing a lid. The instructions that you got with your pipe are probably rather generic, so they include whatever they might think is a possibility.

Here is a picture of a typical system on a 550. The lid is the item at the very top (duh).

[Kaiser Sosei]

Sure you didn't get an 1100 exhaust? That sounds like the directions that I got with mine.

[Flyboy]

Yeah, 850 airbox does not have a lid, the later liter bikes do.
I say put jets first, see what you get, if you still need to tune, then shim needles, trick is to do one thing at a time and evaluate the outcome, so you know what change gave you the results.
if you do a bunch of stuff all at once and find the thing runs like crap, you won't know which change/changes is/are causing it and you will end up chasing your tail.

[oldgsfan]

Thanks for the suggestions and the info. The only bike I've ever worked on is mine so I'm pretty ignorant about others.
the instruction sheet that came with the exhaust is just a long list of all the bikes it will fit and rejetting recommendations.
I'm really excited to be installing these new pipes and have let the bolts in the old system soak in PB blaster all night.

[Don-lo]

You have a beautiful chrome pipe, right? Be aware that if you jet it lean, it will blue the pipes very quickly. Take very short test rides while you are sorting out the jetting, and watch the pipes (and plugs) closely during the process. Raising the needles one notch first may be the safe way to go.