I love the smell of drama in the morning [:-]

 

Iowaguy,

You're a roit lol. Last night I installed the UNI filter. Man the stock filter was so laden with oil and sealant
grease that there was actually a pool of oil in the bottom of the airbox. I can't see how any air could get
through. Good thing I paid a professional to service the bike (That's sarcasm). I also turned the F/A screw
out one half turn so it's at 2.5 turns now. Took the bike out for a 12 mile ride on 45-60 mph roads. It
still pops on decel. It does it most when closing from WOT. Closing from half throttle it just sort of
burrbles but doesn't really pop.

People are saying to tune for acceleration and not to worry about decel unless the popping is excessive but
I don't know what excessive is. The whole popping think is probably not that big of deal but I'm a
perfectionist and won't stop working on it until it's done right. On that point I think I am going to pursue
the issue of backpressure (or in this case, the lack of it). I have not technical basis but it kind of makes
sense to me.

The popping happens when momentum is driving the engine such as it is when I close from WOT or go down a hill
with the throttle closed. As rpms decrease so does the popping. I might construct some sort of variable
exhaust plug to test my theory.

 

i adjusted my a/f screw to 2 turns out and took my air box lid off.... WOW.... what a difference.... runs alot better!!!!!!

man, ive been missing the fun in this thread.......

 

Found this bit of info on a street bike forum:

A BIKE THAT IS LEAN WILL HAVE TO FOLLOWING CONDITIONS.

- Backfiring or popping out exhaust after roll-out ( Ex leaks will also do this ) <----- Definately having this problem.
- Surging @ Cruising speeds or light throttle
- Overly sensitive throttle feel (Jerky)
- Coughing through Intake
- Excessively high Fuel Mileage
- Excessive Heat from Motor <------ I thought it might be running hot on my ride last night.
- White to light tan spark plug insulator <------ I need to check this.
- Pinging or Detonation under roll-on

A BIKE THAT IS RICH WILL HAVE THE FOLLOWING CONDITIONS.
- Poor Fuel mileage under normal riding conditions
- Heavy soot build up on pipes or fenders
- Lazy or Mushy full throttle feel

I also found a thread on thumpertalk where a guy was getting popping after a dealer installed a slipon. He found that the dealer had not used any sealant on the exhaust connections. OPPS, neither did I.

So here's my plan for tonight.

1. Check the plug coloring. I suspect it will show a lean condition.
2. Seal the slipon and head pipe with silicon sealant.

Then I'll test it for popping. If it still pops I'll cover 1/3 of the snorkel with duct tape and test it again. If it doesn't pop I guess I need a bigger main. Probably a 125.

 

Keep in mind popping is on decel with the throttle closed. IE, when the bike is running on the pilot jet circuit, not the main jet. However being too lean on the main jet will cause excessively high exhaust temps (as will the air injection system) which would cause any unburnt fuel to ignite in the pipe. Stock my bike was so lean that the headpipe would glow orange after riding, even conservative riding would get it glowing.

I've found that if I roll out of the throttle easily instead of snapping it shut there is very little popping, which leads me to think that I need to tinker with the A/F screw some more. It's between 2 1/8 and 2 1/4 turns out right now. It can be 80+ degrees outside and the bike will need the choke to start and continues to need it for about 30 seconds before it will idle on its own. Last summer I got carried away and went a little past 2.5 turns and the bike would fire instantly with no choke regardless of temperature, however it would almost stall out at stop signs from being too rich. There is a fine line with the A/F screw.

 

a guy in FL had his bike really rich and was popping, and flames were shooting out..... it can pop when rich too........ FYI.... it was kinda cool seeing the flames outta the klx!

 

My 1987 Yamaha Warrior 350 quad was like that, it had an FMF Chrome Power full exhaust on it with no sparky. Running 3/4-full throttle it had a continuous blue flame coming out and was obnoxiously loud. I went back to the stock exhaust.....although it was neat for a while. It looked like a blue taillight next to the red one.

Going back to Eric's comment, thats what I mean about a fine line. My nitro RC trucks were the same way, it took time and patience to tune them in right, less than 1/8th turn increments on the needles. Very easy to go to lean and then too rich if you tried to tune it like a weedwhacker. This is part of the reason I'm leary on going to a pumper carb because they are so adjustable I'd probably end up chasing the A/F setting with all the adjustments.

 

Here is a fairly fool proof way to confirm your pilot circuit settings. Hope this helps.

http://www.thumpertalk.com/forum/sho...d.php?t=327405

And it's epecially easy since you have that "crappy" Kouba fuel screw that you can conveniently adjust with the bike running. I've got one of those "crappy" Kouba's on my KTM's FCR39 and it works great!!! [sm=smiley20.gif] [sm=icon_ladiesman.gif]

 

What, no more silly cliché's? DC4500, you be sure to let us all know how opening up your airbox and drilling your slide out makes that deceleration popping go away cause that Iowaguy knows his stuff I tell you.