Mac has a lot of exhaust for older bikes. They get the job done but are thin metal and prone to rust out. They don't do a lot of research either as some of there stuff does not fit all of the bikes they advertise it for. For example they advertise a cb750f header for the 77-78 bikes but the header is really a design for a 75-76. The difference is that you can'y mount a 75-76 header on a 77-78 because the oil filter hits (yes you can change to a 75-76 style filter it is just a shorter oil bolt).
You seem like a do it yourself kinda guy, why are you looking for bolt on exhausts for bikes worth less than $1000. If you have welding equipment here is what you do - go down to the local exhaust shop and buy a whole bunch of tubing in different shapes and bends including straight sections. Then just cut and weld till you get your exhaust made. You can use the stock headpipes for the difficult parts if you want. Any custom exhaust shop will charge you more than your bikes are worth for one set.
Or you could do the a-social, Geeto67, approach: Sawzall the head pipes at the muffler junction and just run them as open drags. The neighbors love that wrap-wrap-wrap sound at 6:30 am on sunday. Or if you are not on a first name basis with your local police and don't want to be, get a couple of reducers from the ehxaust shop and weld in some automotive "cherry bombs". Painted black with header wrap on the head pipes they look like fuck-off nasty race pieces. of course if you want to go the show route, British cycle supply carries a whole bunch of different muffler styles including coctail shakers and dunstall replicas. Get a reducer, mate it to your stock headpipes and have it all chromed.
edit: here is Mac's homepage for motorcycles http://www.macperformance.com/store/category.cfm?SID=3&Category_ID=4
What bikes are you looking for exhausts for? list them out, maybe someone has something you can use.
Forgot to mention chambers for 2 strokes are going to need engineering and research. It's all out there on the web, but what I have found is that if there is an enthuasists group for that 2 stroke, someone in that group is always making chambers.
It doesn't pay to mass produce exhausts for these disposible 70's jap bikes because there is no market for a system that will cost 1/3 or more of the purchase price of the bike.
Edited by - geeto67 on Oct 27 2005 2:43:55 PM