look on your needle valve adjusting stem. on the side you will see a set screw. if you loosen this you can stick a T pin or other small metal thing into the hole on the tip of the adjuster and if you tighten down the set screw on the needle adjustment it will be held in there. That will fix your short needle valve stem problem. There is a muffler out by slimline that is a pitts style muffler. If the engine is mounted sideways with the exhaust port facing down, the 2 pitts stacks will stick out the bottom of your cowl. It looks very clean, looks very good, and also is not too loud but it does sound different from stock. I think it sounds very good. Also there is no restrictions like the stock muffler and gives you more power. I have an OS 46FX with this muffler and it is in a cowl mounted sideways like I said with the pipes sticking ot the bottom. I love it. The best part is the pitts muffler is only around $22-$25. Just make sure the package says it is for the 46FX or it wont fit.