Actually, Dan Danielson and I have been making some modifications. We have fitted to my bike the header pipes and collector from mid 90's YZF-1000 along with the BSM carbon fiber muffler I had before. The stock YZF header pipes are about .250" bigger in dia, but the head flanges are same exact dia as the skinny GTS headers and bolt right up. The stock YZF header pipes are welded into the collector. Dan made an alignment jig from the stock header/ cat, cut the header pipes and fitted his own manufactured slip on couplings to the collector and cut the end of the header pipes to align. Otherwise, you can't get the header/ collector on or off the bike as one piece without removing the front swingarm. This also needs to be done because the spacing is a little off (to line up with the exhaust ports). Dan is in the process of making one for his bike from another YZF exhaust and modifying the design of the header couplings. We also tossed the Exup valve (since don't have the control mechanism on the GTS) and used the bearing boss to mount the Oxygen sensor.
Well, what you probably want to know is ... how does it work? My first ride with it was to the annual LD rider get together at Gerlach last month - North of Reno in Neveda. So I had a chance to open her up to see what it would do. Unfortunately it did not gain any top speed - still only 134.7 per my GPS with my tall windscreen, smaller Krauser bags and 46 tooth (1 off stock) rear sprocket. However, at more reasonable speeds (70-95) it ran great! It seemed like I didn't use as much throttle and it really accelerated. I didn't really notice any loss of low end torque, but all seat of the pants. My Fuel Mixture monitor said I was running just right, so the EFI seemed to handle just fine. I was getting great mileage (45 mpg) until I hit open stretches in northern Nev and did my speed run. It really sucked the gas and my F/A monitor confirmed I was running rich. So I'm working on some modifications to the air intake and air box, as I think this is where the restriction is now. I'm hoping to do a rally in Nov from Tx to Calif, so will find out more then. Of course it may be the limits of flow thru the head/ valves, so the jury is still out. I would like to find a shop this winter to put it on a dyno. Oh and one other thing - it sounds great! Not too loud at cruise or steady throttle, but wack the throttle open and it really barks - doesn't sound like your normal GTS. Ask Roger van Saten - he was there when I drove into Gerlach. So wait a couple more months, till Dan and I play around with some other things and get some dyno numbers, he may go into the exhaust business. -- Dave Biasotti // Fremont, CA Date: Sun, 14 Oct 2001 18:16:51 -0500 From: Ed Orozco <[EMAIL PROTECTED]> Subject: Exhaust system I have a '93 stock GTS and I would like to improve the power of the bike by way of reducing the weight of the exhaust system by replacing it with a whole new one without the cat; any thoughts or experiences with this approach; I understand that the bike has to be remapped in order to get the full benefit of the system. ------------------------------ Date: Sun, 14 Oct 2001 19:32:39 -0700 From: Kevin Harrington <[EMAIL PROTECTED]> Subject: Re: Exhaust system Chances are good you'll be disappointed. I think the major restriction is the size of the header pipes, not the cat flow. You will save weight, and, as long as the O2 sensor finds a place in your new exhaust, I don't think re-mapping is necessary (or even possible). If you want more power done correctly, check the archives for Peter Piazza's modifications, they seem well thought out and nicely executed. I think if all you do is open up both sides of the head (ie-exhaust/intake mods) the power you gain will come right out of the midrange. Check into some Kevin Cameron tuning stuff, I think he has a book for sportbikes... FL Kev
