I am looking for some infos on how to re jet the carburetor, I know TW are set poor at factory for emission control and when I look at my spark plug, it looks very poor... It was also doing lots of back fires on deceleration so I changed the pilot jet for a 34 and 2-1/2 turns on the screw. Seems to be much better and less backfires... My 2 nd plan is riching out the main circuity (main jet and needle) I ordered a 128 and 130 main jet and asked my dealer if he had the shims for the needle, he is going to get back to me. If ever those shims are not available at my dealer where can they be purchased? My TW is stock, no exhaust, air intake modifications ride pretty much at sea level to 1000 feet. The real question is... This is my second TW and my first was stock other the 2 turns on the pilot screw with stock jetting and nice color spark plug. No back fire and nice color spark plug. My new TW started back firing on deceleration and the spark plug is whitish (poor) can something have broken in the carburetor letting air pass through? The first thing I did was remove the carburetor cleaned it out, adjusted the float level because it was off from the factory... reinstalled and this did not fix the issue, so did the pilot jet modification, bike seems to run good but whitish spark plug... so planning on riching the main jet and needle. Any help would be greatly appreciated. Thank you!