I'm trying to make a couple minor mods without messing with the jetting to start out. If I only install a KDX Snorkel and the FMF Q4 slip-on will I be ok leaving the stock jets in? What are the characteristics of the bike running lean?

 

You will be opening up the intake and exhaust, i would recommend jetting. Hard to describe running lean, Ive played with jetting so much that i can feel it when i ride. Maybe like the bike is being choked, or it just feels like its being starved, bogging....

 

You'll have to rejet.

 

If you don't rejet you can run the risk of engine damage with your mods.....not mention running like crap.

 

Just need a bigger main jet, tune the fuel screw a little. $5, it'll run out much much better than leaving it stock.

 

If you rejet your better off with a kit like Dynojet's to change the main, needle and spring. It's not just a matter of a bigger main.

 

everyone bike may be a little different, I tuned with both the dj and 300 needle. My best "fueling" was the 300 needle clip 2, 128 main, 40 pj. BUT, it did not return the best run quality in rel world. N1TC needle had too quick of taper and would bog rich on a climb, high load-big throttle. It also blubbered at high alt unless you rolled on slow. I threw the stock needle back in and it's run fine everywhere I have taken the bike. Only reason I went up on the pilot was to get the fuel screw in farther with an after market screw I was using, since put a better quality one in (keintech) and am now using the stock pilot. Here's the best "fueling" run. Fwiw best power run (don't have a pic) swapped to a k and n filter and stepped the main up to 132.

 

Rimbender, what is your exhaust setup and how are you snorkeled.

Thanks.......Steve

 

I think the slip on alone would be fine without a jet kit but if you touch the intake side I'd jet. If you are lean though the bike wouldn't run the best but it wont blow up just starting it to see. Usually lean damage is cumulative the more it's ran that way the more trouble you might be in.

 

Kdx snorkle (cut shorter so it didn't rub the filter foam). 300 headpipe and muffler with ebay turn down tip, bike was dyno'd with big heavy 5.10 kenda 270 so could show better but was only concerned with the main jet sizing.

also tried K&N and big gun pipe, but decided the way I use the bike I'd leave a couple hp on the table for better filtration and more durable muffler that doesn't need re- packing. compromise.