Okay, over the weekend I did some tinkering.  I re-jetted from 145 up to 155, swapped the stock pipe out for a screamin' eagle style, and replaced the white spacer with two 4mm washers.   I've still got a backfire and I think it's due to my idle mixture.  The brass plug is still covering the screw and I'm trying to figure out how best to get it off?  Anybody got a quick and easy trick for it?

I took my dremel with cutoff wheel, and put a goove on one side.  It allowed me to get behind the plug and pop it out.  

Reason I did this.... I still have a factory plug..... and if our wonderful EPA changes laws (no tampering), I'm ready.

Verslagen1,
   You are da man!  Drilled it out (put tape at the 1/8 mark so I didn't #$%@ it up), put a screw in it, and yanked it out.  I put a cutting wheel on my Dremel like T Mac and thought that might be easier, but it was a bad angle for someone who doesn't get along very well with power tools.  The backfire on shifting is GONE.  I still have a little backfire on the down-shifting so I've taken another 1/2 turn (2 turns out total).  It's just minor tweaking from here.  Thanks guys!

When I re-jetted, I only changed the main jet (from 145 up to 155).  I didn't mess with the pilot jet.  I think the '05 comes stock with a 47.5 pilot jet.  Lancer sent me a 55 pilot and I'm wondering if I should have put that in?

Yea, I've been testing all evening.  I'm out to 3 turns and still can't get it to stop backfiring when using the engine to decelerate.  However, NO backfiring during shifting.  I was wrong about the size of the pilot jet for my '05.  Since '95 they have been putting a 52.5 pilot jet in there.  I bought Lancer's JETSET which includes a 55 pilot jet which is what I think I'm gonna drop in later this week.

I noticed in the repair manual that back in the 80's they used a 55 main jet and a 47.5 pilot jet.  Wonder if there's a reason they went down a size instead of up??

Reelthing wrote on 04/08/08 at 17:15:45:
It seems the 90's bikes were put together a little differently for the European market.  The jets on my '95 didn't seem to have any witness marks in the screwdriver slots which usually suggest home tinkering, so what I found in there was probably standard for UK (and I guess other European) regulations.  It had a 55 main and 47.5 pilot, the needle was set to the middle of three grooves but there was no spacer - that must have been removed by a previous owner (I'm the 8th and it's only covered 8000 miles!!).
Despite having the richer jet and adjustable needle, it still had a blanking plug over the idle mixture screw.

As our emission regulations were a lot more lax then, and the rest of the bike's engine specs are identical from the 80s to present, it has suggest that Suzuki think you need a 55 main even in a totally standard bike.

KwakNut wrote on 04/09/08 at 00:26:08:

Hope you mean 155 mainjet

in the mikuni spec sheets - it looks like the taper or rather the length before the taper begins was different as well pre-95 US -



4 different needles seem to have been used in the bs40 on the savage:

5c16 3 slots L 56.90mm D1 3.0mm K1 15.7mm
5c17 1 slots L 56.90mm D1 3.0mm K1 15.7mm
5c39 1 slots L 56.90mm D1 3.0mm K1 15.5mm
5c40 3 slots L 56.90mm D1 3.0mm K1 15.5mm


If you folks with a 3 slot needle get a chance could you examine the
needle and see which is stamped on it 5C16 or 5C40

if you look it over be sure it's a mikuni needle - should have their
mark on it right before the type stamp - their mark is a square with
a smaller square in it's corner - also a good way to tell if you have
a real mikuni jet or some knock off stuff that may or may not be the
size it claims
 

Yes, Lancer's tuning guide is what I used to tune it.  I just can't find a happy median with the idle mixture.  I'm gonna drop in the 55 pilot (hopefully this evening) and use Lancer's guidelines again.  I'm new to being my own mechanic so its been slow and painful.  One way or another, I'm gonna get my Thumper straightened out.