alyeska 50 Posted February 5, 2017 I have never put a pipe on a bike because I believe the benefit is so marginal for power why bother, but after a lot of back and forth I decided to do it for weight. I have a drz 400 2016 that I built for off road so to cut weight I got rid of the heavy huge original pipe, from what info I could find jetting would be needed so I bough a 25 jet but never installed it because after installing the pipe the bike ran better (less popping on decel) the bike makes more noise but I noticed no power increase, the pipe was an fmf q4, So my question is, if it runs better should I rejet or leave well enough alone? I know it may lean the bike out a little but im not sure its enough to burn the valves or do any damage. any help with firsthand information from a drz owner would be appreciated. Thanks Share this post Link to post Share on other sites
Wintyfresh 46 Posted February 5, 2017 If you didn't also cut a hole in the airbox I definitely wouldn't bother with a 25 pilot jet. Typically you step up to a bigger main jet with a pipe and 3x3'd airbox. Share this post Link to post Share on other sites
Bp619 104 Posted February 5, 2017 Ditto plus the q4 pipe might be lighter but its probably fmfs least flowing pipe hense the quietness. So doubt would change jetting that much. I wonder if when you did pipe it also realigned front pipe and thats why some of popping is gone. But on a drz the 3x3 mod and jd jetting kit is magic Share this post Link to post Share on other sites
alyeska 50 Posted February 6, 2017 Thanks for the info. I did choose the q4 for it quietness and it sounds like I should just leave it as it is for now and maybe in the future do the airbox and jetting if I need to gain a little more power. Share this post Link to post Share on other sites
Bp619 104 Posted February 6, 2017 15 minutes ago, alyeska said: Thanks for the info. I did choose the q4 for it quietness and it sounds like I should just leave it as it is for now and maybe in the future do the airbox and jetting if I need to gain a little more power. Not just about power with the airbox and jetting bike runs alot better and maybe better mpg thats atleast advertised, while in there do kickstand safety switch mod Share this post Link to post Share on other sites
Getsmacked440 0 Posted February 7, 2017 You won't gain any mpg if you jet it. My 440 E with q2 gets 20-22 mpg if I'm easy on her. I have a different carb than your bike. And don't think opening up the air box is needed if your not gonna jet it. Share this post Link to post Share on other sites
350thumper 336 Posted February 7, 2017 Put in the 25 pilot jet. The extra 2.5 fuel at start up will assist the M/J's top end powerband. Resulting in better torque curve on a Dyno, and increased engine longevity. DO NOT cut the air box open! The piston valve under the diaphragm will have a tough time lifting the jet needle out of the jet holder. Share this post Link to post Share on other sites
