jhogie, believe it or not the four stroke exaust is hotter than a two stroke. The reason is that the four stroke doesn't fire every time, so the engine is not being 'washed' down with alcohol, octane, therefore the heat is greater. With the two stroke the fuel is being fed up the intake side of the engine cooling it each stroke. Many would think otherwise because the four stroke fires every other time and therefore there should be less heat. Believe me, it will melt an exaust deflector made for a two stroke. That is why there is one for each.
The type of muffler is important for smoke. If it is not a 'smoke' muffler it will be marginal at best in many cases. You can however wrap brass tubing around the muffler, tightly, to pre-heat the smoke fuel. The more wraps you get on it the better it will vaporize. Use a three foot piece of 1/8th or 5/16th, which ever fits the supply tubing best. Don't solder any pieces together because it will melt from the heat. Be sure and aneal the brass tubing before wrapping it. If it flattens a little it will be alright but don't kink it too much, the back pressure might blow the line off.

Usually, the smoke mufflers are set up this way but with the coil inside unless they have found a way to do it otherwise.
Too bad the four stroke muffler is welded instead of screwed together like the two strokes, then you could put a coil inside and have your smoke and eat it too!
Now, just in case you get the bright idea to cut the end off of the muffler you have, and put the coil inside, be fore warned that if there has been fuel run through it, it will not weld back together very well because the aluminum has expanded and saturated itself with oil and the weld will spatter and look like a dirt dobber did it, I don't care how good a welder you are!

Well, that's my take on the matter. Hope I have shed some light from another direction that actually helped.
Take care and write soon ya hea!
bird.