I recently put the blue collar bobbers drag pipe on my savage and rejetted to suit. I used a 55 pilot and 155 main as I'm pretty much sea level and am wanting to put a cone filter on soon. I shaved spacer to about 2/3 to 3/4 (I think haha). I still pop like crazy on decel. Header clamp seems tight and muffler is sealed with silicone. I didn't notice a leak before I wrapped pipe and muffler. I have started getting a pop on shut off which I didn't have before and also loud backfires every now and again. Would some small washers to decrease spacer size even more eliminate the problem? also idle scre is around 1 3/4 turns out Cheers

I have the pilot screw at 2 screws out now which seemed to increase the RPM a little but to be honest it's hard for me to tell by ear when i go further, is the change in RPM meant to be very significant?

Haven't checked plug yet but will check today.

When I set mine I went for a ride with a small screwdriver in the shirt pocket. Small adjustments at lites until I had it juuuuust rite..

Snug the header studs up a little, be ever so gentle,, do it while its cold..

A candle flame can show a leak,,, or so I hear,,
I wonder if a lite powder would..

Routy:  I am glad you posted your backfire comments.....I was wondering if I was the only one that felt this wayl  The last few weeks I have been jetting my new Mikuni VM36 using an oxygen sensor.  I have been changing jets to get a mix just slightly richer than the economy mixture of 14.7:1......and slightly leaner than the 12.2 ratio that creates maximum power.  I believe I have it dialed in really well right now....and my jetting has been focues on making the engine run smooth and efficiently.

When using the O2 sensor what I discovered is that when you cut the throttle off completely while slowing down or shiftin gears - the engine goes very lean.  The fuel flow has basically stopped because the needle has dropped down into the needle jet and closed off the flow from the needle jet and main jet.  The only fuel flow that is available is coming from the pilot jet...and that is not enough to provide a burnable mixture.  The TEV valve is supposed to provide additional fuel on the CV carb to correct this lean condition.

I am not ever getting loud rifle shot backfires when I ride - but if I completely close the throttle while shifting or slowing down I do get a lot of pop, pop, pop, pop.  But........if I don't close the throttle completely while shifting gears or slowing down.......the engine does not backfire or crack or pop.  The throttle doesn't have to be opened much, and it is not affecting the rate at which I slow down as it is not enough throttle to cause the engine to accelerate....it is just open enough to provide some extra fuel so the mixture will burn inside the cylinder and not in the exhaust pipe.  

I think that changing jetting to stop the engine from doing the rifle shot backfires might be OK....but jetting to eliminate all rumbles, pops and gurgling from the exhaust is not productive. If you are richening up the pilot circuit in order to stop all backfiring - your engine is going to be running too rich most of the time.

Cheers for that guys, I'll try playing with the throttle next ride and ill grab a bbq lighter today. The pops don't bother me too much, it's mainly the occasional bangs that I want to get rid of.

Plugs a matte black sooty colour, would this be the fuel mixture screw too rich?

Well I found a small leak inbetween the muffler and header which I believed I fixed.
Can't find any other leaks, Still banging.
I've ordered a 57.5 pilot jet, just to see.

I put in a new sparkplug which quickly became black and sooty which I thought indicated that I'm too rich, but im still backfiring?