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How to unplug exhaust can
#1
I have a used bmw f800gs exhaust can fitted to my 500cc scooter. Previous can got too loud and I had this one in the  cellar. 
However, performance dropped through the floor, and I checked the strength of the exhaust gasses, and there was practically nothing. 
I can't find a diagram of the internal design, so I am thinking  just drill a hole 
in the front with a long bit. It is not possible to come in from the rear, as the end bit slants down to the road. What do you think?  Feasable? Other ideas that don't cost?
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#2
Update: I took the can off, and after close examination, it looks like from the front, 1/3 a large chamber, then two pipes on each side go off to the rear.
From the rear, using a slightly bent threaded rod, I can extend the rod all the way down to the front until 1/3,where the front chamber is.
So, it seems that there is a blockage at the end of the two pipes, as there must be another chamber where the gasses flow through to get to the pipe going out to the rear.
This can has a s/s shell, with another inner can of regular metal.
All welded together.
So, grinder at the rear weld on the s/s shell,and probably grinder applied to the inner can at the rear as well.
Then remove the blockage and possibly refill with something and finally weld up(I will have to employ someone with this part)
This is looking like a lot of work.
A bike shop is willing to sell me a used akropavic can for 2.5
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#3
Hi Xsel777, sounds to me like you have a CAT there and it's blocked through usage. Either get somebody who knows welding to cut it open and gut it, or replace with a lighter de-catted zorst. I can sell you a new Delkovic which will improve the performance of your bike for around 3K.
Unfortunately you are in CT so I won't be able to get it installed for you as well.
MM
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#4
Hi. My understanding is that this model bmw has the cat on the pipe in front of the can.

Anyways, I found another can, a free flow, that I repacked, but it sounds like there is no exhaust, so I must resolve this soon.
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#5
Update:I cut open the rear of the can, about 2cm in, and found that the whole inside part slid out, leaving only the outer s/s shell, and front pipe.
Most of this inner part was perforated wrapped with wool packing, in 80% condition.
The 1/3 chamber at the front, i could look into it properly, now that the complete inside part was out.
There is a plate welded in to make that chamber, with the two pipes poking through. That plate had rusted off, and was jammed tight against the rear pipe going out, effectively blocking it.
But I also see a tiny/thin chamber at the rear of this inner perforated inner can, and I think that could be steel wool in there. I wonder if that is also blocked, because blowing through with my mouth, I don't feel much air coming through, but I am willing to accept my testing methodology is low quality.... ?.
Anyways, I am knackered now, so I will get the front chamber plate welded back and the shell rewelded, and see if it will blow out the blockage from the front mini chamber. If not, I will cut open the front seam, and see what is happening there.
A lot of work, but not 3k, so a saving.
Once done I will paint it black and nobody will be the wiser.
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Burning up the Tarmac
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#6
Here are some pics


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#7
Well folks. It was a success. Nice and quiet, once again. Ok, not quite; more a deep throaghty throb. A deeply satisfying fix.
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#8
Glad for you that the exhaust is all sorted. An exhaust is a pain in the arse to repair with out the right equipment.
At the beginning of the month, I cut open the exhaust can from a friend's 4 stroke golf cart to find a blockage. After cutting open a few inspection vents, I found the blockage located in the first 1/3 of the exhaust. Using a gas torch, I managed to burnt away the blockage, but the closing of the inspection vents gave me up hill. I kept on burning holes in the thin metal when I tried to arc the exhaust closed. Eventually I took the exhaust in, to have it mig-welded.
I wouldn't mind owning a mig-welder, but there aren't enough jobs to justify such a purchase.
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