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AaronADV
11-15-2007, 10:59 PM
We couldnt bring ourselves to spend 1000 plus dollars on an exhaust syatem. So we built out own, This is A prototype that we built out of some scraps laying around the shop. We are taking it to the Dyno in the am to see what we have.
Here are a few pics. if this works out I will build some really nice ones.

Ab

AaronADV
11-15-2007, 11:01 PM
few more

PainterDude
11-16-2007, 01:50 AM
Great idea, How loud is it??? I love that little carbon can, where can I get one.?...I need for my YSR 250F...

RZRob
11-16-2007, 02:26 AM
That's cool. I wish I had what it took to build something like that. I want prominent dual exhaust. It's a twin and I want people to know it.

RZ Rob

AaronADV
11-16-2007, 06:51 AM
The can is from a 916. we shortened it about 10 inches. Its no louder than one of our 450 singles.
I thought about doing 2 of them, but it was a bit to busy under the seat.

Ab

conman
11-16-2007, 07:48 AM
do you think it would be possible to use the Dual slip-ons from a crf250 from say----FMF or Pro Circuit attached to a GPR twin setup or are they too big as well?

AaronADV
11-16-2007, 08:23 AM
do you think it would be possible to use the Dual slip-ons from a crf250 from say----FMF or Pro Circuit attached to a GPR twin setup or are they too big as well?

Sure, There are alot of mufflers out there, Not that expensive. Where are you located
Ab

conman
11-16-2007, 09:21 AM
Sure, There are alot of mufflers out there, Not that expensive. Where are you located
Ab

Phenix city Alabama.

I have a sxv 450 with the GPR's on it and it is LOUD as hell. on one hand I like the sound but on the other it gets old quickly.
I just want something that looks good, makes good power but retains the twin look and isnt as big as a football:) I know the Slip ons for FMF or pro circuit arent THAT big, thats why I am interested in those.

smstroben
11-16-2007, 11:07 AM
this is what you want. http://www.apriliaforum.com/forums/showthread.php?t=134041 post #13.

RXV_Poor
11-16-2007, 11:12 AM
Very nice work. It looks like it would work well on a road course.

AaronADV
11-16-2007, 12:13 PM
Very nice work. It looks like it would work well on a road course.


Thanks, We looked at the sil exhaust, it cost to much, I didnt want to spend a ton on the akra just to have it destroyed in a crash. We built ours out of an old Ducati 851 header, and A ducati 916 muffler. Took it out for a spin today, seems like it lost a little on the bottom, but gained mid and top. We are going to try an get to the dyno this weekend and do a back to back ours aginst the stocker.
I am really hoping it pics up alot on top since that is where we run ours on the road courses

Ab

duc slayer
11-16-2007, 01:26 PM
have you seen what Irie did to teh Akro pipe, a quick cut and a weld, and it became an underseat exhaust

orangerider2
11-16-2007, 02:20 PM
I tried several similar designs, they too lost power on the bottom but seemed to equal the stocker everywhere else, so they were of no benefit, but they sure sounded nice.:cigar:

AaronADV
11-16-2007, 03:10 PM
I tried several similar designs, they too lost power on the bottom but seemed to equal the stocker everywhere else, so they were of no benefit, but they sure sounded nice.:cigar:

Do you know what map you started with? we have the tune boy so that might save us a little dyno time

Ab

orangerider2
11-16-2007, 03:29 PM
With the Tune Boy you can go to higher levels of performance. From the average off road rider standpoint going to a different exhaust without Tune Boy, a Power Commander, or an hour or two on a dyno is of little benefit. I have found most performance gains without using Tune Boy or a Power Commander, was a system with equal length headers, on the 450 i also prefer the original unrestricted mapping, the other mapping takes away the edge that the original has, just personal preference, I`am considered a pro level off road rider.:cigar:

orangerider2
11-21-2007, 10:26 PM
Any progress?:cigar:

AaronADV
11-21-2007, 10:58 PM
Any progress?:cigar:


Took it out for A spin, it seemed better on top, lost a little on the bottom, which is fine, we run a 38 tooth rear sprocket. Gonna try an get it to the dyno this week.
My next project is to notch the swing arm for chain clearance with the small rear sprockets.

Ab

AaronADV
12-15-2007, 04:01 PM
Any progress?:cigar:

Well here is the skinny

Our exhaust pipe with the AF1 single stage airfilter, Stock derestricted year old map, 39 tooth rear sprocket and U4.2 race fuel produced on a dyno jet dyno

71.9 hp @ 9800rpm, The curve was real nice no peaks
47 FPT @ 8800rpm, again nice curve, pretty flat across the board

The air fuel was off due to the map. We didnt want to run it to much due to the leaky cases. With A good map I would think 74-76 might be possiable

Ab

gunzz
12-15-2007, 06:46 PM
so stock headers/stock map with this exhaust made that power? if so thats perfect and i better start welding. cant hear my own bike to shift when im close to others, and im perfectly happy with equal to stock power as long as it louder.
i realize a/f was a little off, but is it "safe" across the board?

thanks for doing this man, and the dyno, lots of us have been wanting to do something similar