Ok, I have to admit right at the start this isnt my work and its not something that appeals to me to do, I quite like the length of the standard exhaust. However I'm sure there are many out there who wish the standard can was a lot shorter and wouldn't mind having a go at modifying it. Well with no expense spared, here for your perusal is a step by step instruction I have stolen, I mean borrowed from someone who looks like they knew what they were doing. ;D ;D
Remove the pipe and take off the rear end cap (3 screws).
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod1.jpg)
I used a 4 1/2" angle grinder with a 50 grit flap wheel sanding disc for most of the grinding but I had to use my smaller 4" one with just a regular grinding disc in a couple of places in the corners. The flap wheel disc does a much smoother job.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod2.jpg)
Grind from the end of the muffler carefully removing material until you just see the parting line between the end cap and the outside muffler body.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod3.jpg)
Work your way carefully all the way around.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod4.jpg)
When you can see the parting line all the way around, take a very sharp narrow tool like a gasket scraper and tap it into the parting line to gently separate the 2 parts. I had my son hold onto the muffler body while I pulled out the guts of the muffler. It takes a fair amount of effort to pull it out. The mark you see all the way around the end of the muffler is just dirt that was under the end cap, this gives you an idea how much it will cover when you put it back on.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod5.jpg)
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod6.jpg)
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod7.jpg)
Just pull out the inside portion of the muffler. It looks like this inside, there is a layer of steel wool type material that sits right up against the guts of the muffler and surrounding that is 2 layers of fibreglass muffler packing like I use on my dirt bike muffler when I repack them. This will all have to be removed carefully from the muffler case and wrapped around the guts when you put it back together.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod8.jpg)
The baffle portion looks like this.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod9.jpg)
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod10.jpg)
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod11.jpg)
I cut 4" off the front end of the baffle using a cutting disc in my 4" angle grinder. As you can see in the picture that removes the spark arrestor screen from the baffle.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod12.jpg)
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod13.jpg)
I then carefully measured 4" from the end of the muffler case and made a line all the way around the outside and marked it with masking tape. Then I cut off the 4" piece using a cutting disc in the angle grinder again. Make sure to wear a dust mask as some of the muffler packing will be cut and I'm not sure what it's made from. It could cause irritation if you breathe it in.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod14.jpg)
Here are the 2 pieces removed, 4" from the FRONT of the baffle and 4" from the REAR of the muffler case.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod15.jpg)
Make sure to test fit the baffle into the muffler case before you wrap on the packing. If you did not cut enough off the baffle there will be a gap between the end of the muffler case and the baffle end cap. I took the packing material out of the inside of the muffler case and installed it on the outside of the baffle. The baffle will not go back into the case without folding the packing material and pushing it all to the front of the muffler. I wrapped the steel wool stuff on first and wrapped it with masking tape in a few places to hold it tight. Then I wrapped the fibreglass material around that and again used some wraps of masking tape to hold it in place. The masking tape will eventually burn away. Some people use mechanics wire but I prefer masking tape. I forgot to take a picture of it before I pushed it back into the muffler case. This takes a little patience; make sure the packing slides in without bunching up.
When the baffle was back in the muffler I soaked an old tee shirt in water and laid it on the muffler case very close to the weld so the heat from the welding would not burn the paint.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod16.jpg)
Go slowly here, I just did 3 small spots at a time then allowed it to cool a bit before going on. I used small vice grips to pull the muffler case down to meet the end cap of the baffle. Move to a different spot often during welding so you spread the heat evenly and avoid distortion. When all the welding has been done you may need to remove a little material so the aluminium cap will fit back over the end of the muffler.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod17.jpg)
A little high temperature black paint (semi gloss) will prevent rust. If you have been careful none of this will be visible when the aluminium end cap is back in place.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod18.jpg)
Now just install the cap and bolt it back on. As you can see the end of the muffler extends just back of the pannier now and looks better. I don't think anyone who isn't familiar with the bike would even know it's been modified. It sounds stock except it is very slightly louder.
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod19.jpg)
And the finished product......
(http://i151.photobucket.com/albums/s139/Jaffa_Cake101/GTR%20Exhaust%20Mod/exhaustmod21.jpg)
Pretty neat job.
LW, I'm impressed. Looks less like a potato launcher and more like an exhaust. How long did it take you to do? What's the sound like?
Flies next? ;D
NB, you haven't read the first paragraph have you.... :)
Youv'e seen my GTR its black not silver and I have a GB plate on mine! I just put this on here because I thought it might appeal to some. The guy that did it said it took about two hours to do.
Ah, you had me there. It didn't click that you had a black GTR - that what doing 110 hours in a week does to you
I wonder if chopping it down affects the exhaust emissions?
LW do you ever sleep ;D
I wouldn't have thought emissions would be effected, pussy cat should still do its job OK
Are emissions part of the bike test yet??
Quote from: Nygie on December 08, 2010, 07:27:05 AM
LW do you ever sleep ;D
I wouldn't have thought emissions would be effected, pussy cat should still do its job OK
Are emissions part of the bike test yet??
Morning, no I very rarely sleep, its over rated. ;D
I dont know whether or not emissions are part of a bike test or not to be honest, I was just thinking out loud. By the way have you managed to get out on your new bike yet?
Nope :'(