Finally got new exhaust installed...

[coreytrevortpb]

Howdy. Last night I finished installing my new slip on.  I bought it for $60 on ebay; it was a Yosh RS3 stainless off of an R1.  It had some road rash and dents on it so I decided to saw it down and make it into a shorty pipe.  I was able to cut off the section with all the damage and use only the good part.  It ended up looking awesome.  I repainted the header while it was off and got the rust off of it.  Anyway the thing sound freakin sweet.  Really deep sounding and growly.  Its not too loud just idling but when you open it up, it gets pretty noisy.  I can already tell that I need to rejet, and I have an uninstalled Factory Pro stage 1 jet kit here that is going in soon.  Any suggestions on what jetting/needle combinations to start with?  The bike is a stock 91 bandit 400 with the slip on yosh, stock airbox, stock filter.  While I am tuning this bike, would I see any benefit to switching to a K&N filter or modding the airbox?  If so, what is the best way to mod the airbox? Thanks.

[El Dopa]

If so, what is the best way to mod the airbox? Thanks.

What you're trying to do when you fit a new exhaust/filter is improve the airflow, but it's a delicate balance.

Therefore, the 'best' way to mod the airbox is to make reversible changes, so you can at least put it back how it was before. The easist way to do this seems to be to drill holes in the top half, above the filter. If that makes the bike run WORSE, you can tape over them with duct tape.

My disclaimer on this is that I've never done it myself.....

Dunno about the other stuff, but my Bandit's got a full Yosh system on it, and I'm running stock filter and airbox - it's still 'punchier' than a friends stock 400.

[interfuse]

Follow the instructions that came witht the jet kit and tune from there. Making one adjustment at a time until you get it right. Or take to it a pro and have them do it quick and proper.