I have heard the newer gasoline blends make it difficult to get a plug reading. And that smog equip is injecting air into the exhaust manifold, it then ignites any unburnt fuel in your exhaust. Get rid of it.

 

I've been into snowmobiling for several years so I have read lots of stuff on the Dial A Jet kits. They're expensive, which is the drawback for me...

Mike Cory from DynoJet got back to me in record time (only a couple hours) and suggested going from a DJ116 to a DJ120. Since it's sluggish around 6000-8000 RPM, that makes sense to me (from my limited understanding of jetting). As I understand it; < 1/4 = Pilot, 1/4 - 3/4 = Needle, 3/4+ = Main. I'll give the main jet a tweak and see how she runs after that. Further supporting this is the fact that my mileage has not changed ONE BIT since re-jetting it, and adding the KDX snorkel and DEP pipe. I was getting 65 MPG before mods. Post mods - I checked it yesterday after doing 90 miles of dirt/gravel roads, and I was right at 65.1 MPG.

I'm sufficiently convinced that the popping is not harmful, and therefore won't waste any more time and effort to eradicate it.

 

At first I tried to get rid of the deceleration popping by turning the mixture screw out. I got rid of the popping, but I had a hard time starting it when warm and a slight rich smell. I turned my mixture screw back in a 1/4 of a turn and now I've got no rich smell and it fires right up when warm. Granted the popping is back, but I figure it's the least of two evils. Overall, I'm very happy with the performance throughout the throttle.

 

Well, I couldn't stand it any longer, so I went out in the garage at 9:30 last night to re-jet it. Since I didn't need to fiddle with the needle, I tried loosening the duct clamps and spinning the carb while still ON the bike. Had to remove the one screw that holds the throttle cables to the carb, but I was actually successful in getting it re-jetted WITHOUT removing the carb, fuel tank, or even the side covers from the bike.

Fired right up this AM, no choke. Throttle response seemed much improved on my way to work this AM. I will further test with a trip around the flightline at lunch time today. Popping is still there, but I'm not going to worry about it anymore...

 

Exactly, that's why I'm wondering if it's a 1:1 smog equip = popping

 

Yes, the smog equipment of the kind on some Kawisakis can cause popping and can cause extremely hot head pipes if the mixuture is a bit rich...but...I think you'll see the popping in most cases where the smog component has been removed, so the elements outlined in that Thumpertalk article I linked to still apply regardless of any smog equipment.

 

My smog cr@p is gone. Ripped it out before I even re-jetted... and mine pops like a motha... so I don't think we can make the correlation (above).

 

Are you sure you don't have other places (aka leaks) where air can get in the exhaust?

 

Changing from the DJ116 to DJ120 fixed things 100% for power in the 6k to 8k RPM range. I'm happy... what a difference!

As for the popping, I'm not going to worry about it. I did locate LOTS of exhaust leaking past the joint where the tube flare attaches to the muffler part. I don't want to seal it off, because that's where it comes apart for re-packing. It's held together with 4 small screws. I tightened them, but don't want to strip the holes. There's still plenty of exhaust escaping there. If I seal it, it's going to be a pain to get it apart.

 

When I first put on the slip on, there was lots of popping. I plugged the tail pipe and used a smoke stick (e.g. cigarette) around the connections and found several leaks. Fixing them made a huge difference. It didn't stop completely, but much better.