My Last Mod Question (I promise)

This is it, I am just about there but want to run everything by you guys one last time and make any final tweaks you recommend. I have done all of the initial mods - YZ throttle screw, Zip-Ty fuel screw, pulled muffler baffle and airbox snorkel, cut the grey wire and rejetted. As far as jetting I put in a #48 pilot, #68 starter and from the JD jet kit I used the #170 main and the blue needle at the third groove from the top. As per the JD insturctions I set my fuel screw at 1 3/4 turns out. When I went on a five minute test ride I noticed an increased popping sound on deceleration - usually just one pop but loud enough to clearly hear it. I don't think it is lean since I am using the largest main jet from the JD kit and have everything else set at their recommendations. What could be causing this? My initial thoughts are to open the fuel screw a little and maybe raise the needle a click or two (although I don't like the idea of continuously opening the carb to keep making changes). Could this be caused by the AIS system? Is this popping typical in a bike after all of the mods are done? And finally, should I worry about this damaging my bike or is it more just an inconvenience? Thanks.


...Is this popping typical in a bike after all of the mods are done? And finally, should I worry about this damaging my bike or is it more just an inconvenience? Thanks.


Well, first off, if you still have the goofy AIS, you are NOT done with all the mods! Now get busy! :cry::cry: Popping can be from extra unburnt fuel igniting in the pipe, but AIS will also give the extra shot of air to ignite extra fuel. Deleting the AIS might cure the popping! :cry:

My bike was jetted before the removal of the AIS, it ran great but I noticed a very slight popping on deceleration, now that I've removed the AIS the bike runs perfectly. You need to PM Lowedog and get it done, a simple mod. Good luck...

I agree with these guys on the AIS removal. Mine was tuned just fine but, until I removed the AIS I had backfire on decel.

What is your elevation/temp right now??? Judging from your specs it doesn't sound lean, maybe a tad rich but not lean.

Thanks for the help. I will PM Lowdog and get the kit straight away. My riding elevations are usually between 1000-2500 feet and the temps are below 50 for a couple more months. I went and raised the needle one click last night so I'll see what that does. If I was rich already I guess things will get worse.


Sorry for going on and on like this, but I need a little more advice. When I rode my bike for about five minutes today after raising the needle one click it seemed to really be missing the top end, at least in first gear. It had plenty of pull down low and in the middle but then it just seemed to stop when it got towards the top of the power band. I didn't notice this last night when I rode it before I raised the needle but it was dark and wet and I might not have opened the throttle all the way. This seems really odd to me since loss of power on top indicated too lean of a bike based on what I've read and as Texas4Play stated above, if anything I am running too rich. Could I just be using all of the first gear power? If so it sure goes through the power band in first gear quickly. Oh, BTW I closed my fuel screw to 1 1/2 turns and it didn't help. So now I am at 48 pilot, 68 starter, 170 main, blue JD needle at 4 clicks down and fuel screw 1 1/2 turns out. Help, please? And on a side note, when should I do my first oil change? I am just about through with my second tank of gas. Thanks.


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