2 stroke exhausts

[shed]

I read an article by clive garner in last months TBM (uk mag), that said - if i understood him correctly - that he tried cutting the stinger bit off of a 250 2-stroke expansion chamber, then pushed it inside the chamber and welded it in place. I think he then stuck a bit of pipe on the end to direct the exhaust toward the rear of the bike. He said that it seemed to make similar power to standard, but with a similar noise level to the standard silencewr (he wasnt using a silencer). Apparently the suzuki GP bikes in the 80s were doing a similar thing for packaging. Has anyone heard of this before?

I also recently saw a picture of a good enduro rider on a 2-stroke that had a trials type expension chamber fitted to it. I guess it gives a better powerband for technical enduros.

 

[cujet]

You bet! I have done this on 2 strokes for years. My first attempt was with a converted roadracing RD350. That bike was so loud even I could not stand to ride it. So I tried this trick (which was published in the "Two Stroke Tuners Handbook') with very good results. It did loose a tiny bit of top end power, but so what. Restrictive silencers really kill the power.

I also see a variation of this theme used on certain PWC (jetski) pipes, also with good results.

Chris

 

[bwalker]

The snowmobile pipe company PSI made two types of pipes a few years back. They called them modblaster and stockblaster. Thge only differance was the stock blasters had internal stingers as mentioned above and where way less loud.

 

[shed]

cool, i might try it on a spare expansion chamber so I can make the bike street legal and not attract too much attention!