Okay, so if all goes well, I'm purchasing a slip on and header today for my bike..

Here's my question, after how many mods do I need to rejet, and any suggestions of what jetting to try given that I live just above sea level and do most of my riding under 1000' in NJ/PA/NY

Here's what I've done and will do by the time the new piping is installed:

Needle Kit (installed by PO, any way to tell by look which it is?)

Drilled Slide

Cut original snorkel WAY down (like an full 1" left on either side of the lid with a heavily sloped opening and as much center block removed as possible. (eventually I'll probably either remove the lid or get the high flow snorkel but for now just doing that has made a marked difference)

Big Gun Evo R slip on.

MAYBE NEW header that matches, I will probably try with the stock header first since I'm a big fan of torque for my riding and what I've read says that I'll lose torque installing the header. I might try it both ways, hopefully no need to re-jet for this change alone.

So, do I need to rejet, and any suggestions of where to start ... and I'll see if I can get that nifty more easily adjustable Idle jet piece too.

 

If you don't know what you have now, I'd open it up, put a 125 MJ in there, and get rid of the lid. It should work perfect with your slip on.

 

Even if you only do the slip on, you will need to rejet. At that time you can take your snorkle and throw it in the trash. You could do the same with the airbox lid, but I thought the intake howl was somewhat obnoxious. I put the lid back on but drilled some extra holes in it. I wouldn't worry about losing bottom end power with the header. Just go for it! You'll be happy with the result!

 

Okay, so I found out the Big Gun exhaust was going to a different buyer and this was of course the perfect excuse to go buy the FMF Q4 and the Mega-Bomb header from my local dealer.

Local dealer did VERY right by me and knocked off 25% on both so that header, pipe and a synthetic oil change with filter cost me under 5 bills. I'm beginning to like this guy!

I'm at 700' above sea level

I saw the suggestion for a 125 main jet previously but I'm curious if anyone in NJ has a 250 with header and slip on and an opened up airbox that can give me a starting point for jetting and turns. I'll read forums for ideas but rather than buying a kit with all the jets I dont need, I'd rather just order what I do need.

 

I'm at 800', and have that pipe (read my sig). Go 132

 

Perfect, are you still using the stock Idle (35 I think it is)?

 

Yes, it's stock.