Exhaust Components

greg brillus

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Hi there Bill, no my seats just fine now that I've fettled with it...But I do have to redo my exhaust now that it's hitting the ground on right handers, last run a couple of weekends ago it hit and I felt the back wheel skip out a bit......:eek:......Now you cant go around with that lurking on the back of your mind can you...? Or the next thing on my mind might be the bitumen.......Cheers....Greg.
 

vibrac

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If you are wanting to forget about grinding away pipes there is really only one place.....
bencorner.jpg
 

Bill Thomas

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I tried the legs out the back trick once !! ,God know what I looked like !!, Roger came by me on the, At the time, Latest Ducati 750, = 140mph one, We just got on the back straight at Silverstone, I was on my Standard ish Blue road Twin with twin Ex' pipes, And I got him !!, Don't know if it was the Legs Bit, But I will try anything !!, Not good for the Nuts !!. But as soon as we got the bend, He was past and away !!, Good Times, Cheers bill.
 

greg brillus

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I get what Tim is on about..I just cant bring myself to have up swept pipes, I'll just sling them right under the engine, and forget about mufflers. Who really wants to hide that sound anyway.
 

greg brillus

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How do they conduct your sound level checks....? Here they use to check by holding a sound level meter about 1 meter behind the exhaust pipe and get you to free rev the engine to say 4000 rpm. Now they check at locations around the track at a distance of 30 meters from the track surface, but mostly at the start/ finish line which is usually the main straight where you are on full throttle. Only track I have had an issue at is Lakeside which is just north of Brisbane city here in Queensland, and their track limit is 95 db at the track, measured right at the start/finish line. At first I went to a lot of trouble to keep the exhaust quiet, that's why I went to a two into one system with a big muffler....turns out I was way over the top.....Bike put out less noise than a standard Rapide. When I went out on the track, they all said...."We can't hear you" take that ruddy muffler off so we can hear it. So I just worked back from there. The exhaust was a work of art...although Davidd did warn me of the system bottoming out on corners. Being such a novice rider, I guess initially I wasn't pushing it that hard in the corners, but I soon realized that my opposition was flying past me about 1 second per corner, now I am trying harder, I have found the exhaust hit the track surface, and I actually felt the back wheel skip out.....that was enough warning for me. I think the suspension had sagged slightly as well, so I have set it up again to help give more clearance under the engine...remembering I am only using one spring each, at the front and rear, which is probably working quite hard given the springs are not that big. But I may be able to do something about that later on.
 

davidd

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Maybe Eddie will shunt us off into a Racing Pipes thread so we aren't diverting Steve's thread!

I get what Tim is on about..I just cant bring myself to have up swept pipes, I'll just sling them right under the engine, and forget about mufflers. Who really wants to hide that sound anyway.

There are always lots of compromises to make in racing. I had some bad experiences with low pipes hitting the ground and this became a real issue when we were required to install oil catch pans under the engine. The pans took up all the tight and high space under the engine. Additionally, silencers became mandatory and this means there is just not enough space down below. I know many organizations have not adopted these two rules, the silencer and the catch pan, but I knew that they were coming. The biggest motivation was the large amount of time and cost involved in building and testing exhaust systems. Lots of dyno time, lots of track testing and lots of cost building and modifying the pipes. The bottom line is that it is difficult to develop an exhaust system unless you commit to the routing first. If you develop a low pipe it is unlikely that you will be successful in making it a high pipe if it becomes necessary. The development will be quite new if you have to switch to a high pipe. When I made the decision to switch I had to build a new seat, seat frame and modify the F106 to make the high route work. So, I would say that I am committed to it now.

Greg does not have the same rules to worry about. I am quite happy with the rules I run under. The oil catch pan is something I would do even if there were no rule. It does keep oil off the track even with a tight motor. I am also happy with the silencer rule. It requires a more sophisticated approach to the exhaust (which I have not yet stumbled across), but gents like McIntosh have developed nice systems with an increase in power.

Here is a center pipe I used years ago when racing the Grey Flash:

AHRMA 004_edited-1.jpg


The shadow on the track makes it hard to see, but if you have to add a catch pan and a silencer of any length it gets tough. I was using 19" wheels also.

David
 
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