How to remove factory exhaust?


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ksquared
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How to remove factory exhaust?

Post by ksquared »

I recently obtained an RC Performance exhaust system for my 79 CBX. My problem is removing the factory exhaust. I removed the 2 nuts and 1 bolt holding the muffler as well as the 6 nuts holding the headers to the head but it doesn't want to come off (at least without some serious force). Yes the header tubes come out of the exhaust ports and yes the muffler appears loose but it won't drop. I've done this on my CB400F so it's not exactly my first rodeo. Is there a trick I need to know? Another fastener I missed?
79 CBX - 75 CB400F - 71 SL350 - 07 Buell XB9R - 03 Harley V-Rod

EMS
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Re: How to remove factory exhaust?

Post by EMS »

The mufflers hang on two bolts that go through the small bracket and the footpeg plates. One of them also holds the rear footpeg. Make sure both bolts are out

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ksquared
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Re: How to remove factory exhaust?

Post by ksquared »

2.jpg
I removed all of the fasteners in red in the to pictures. Did I miss something?
1.jpg
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79 CBX - 75 CB400F - 71 SL350 - 07 Buell XB9R - 03 Harley V-Rod

jnnngs
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Re: How to remove factory exhaust?

Post by jnnngs »

You need to remove 24 and 30 aswell (first picture).

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Re: How to remove factory exhaust?

Post by EMS »

You did not have to remove "22". The mounting bracket remains on the exhaust. If you take the nuts off and leave the bracket on the hanger, the muffler may bind and not come off. As both Paul and I said, the rear footpeg bolt needs to be removed.

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Re: How to remove factory exhaust?

Post by ksquared »

Thanks guys. I was almost ready to take it in to a local shop. Thing is they know nothing about CBXs and I should be better than this :lol:
79 CBX - 75 CB400F - 71 SL350 - 07 Buell XB9R - 03 Harley V-Rod

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Re: How to remove factory exhaust?

Post by ksquared »

Yay - I got the RC exhaust mounted. Sounds pretty good. Anyone know what the tightening protocol is for the exhaust flange nuts? I took the to 40 inch lbs. If anyone is curious, the factory stock exhaust (complete) weighs 20.5 lbs each side. The RC setup is 10.5 lbs per side.
79 CBX - 75 CB400F - 71 SL350 - 07 Buell XB9R - 03 Harley V-Rod

steve murdoch icoa #5322
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Re: How to remove factory exhaust?

Post by steve murdoch icoa #5322 »

Do you get to keep the center stand with the RC system?
Mike says flange bolts numbers are 8-12 nm or 6-9 ft-lbs.
viewtopic.php?f=22&t=7036&p=72928&hilit ... que#p72928

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Re: How to remove factory exhaust?

Post by ksquared »

Yes, the center stand still works although when up, it rests lightly against the left muffler. Not a problem. It sits about 1/4" lower.
79 CBX - 75 CB400F - 71 SL350 - 07 Buell XB9R - 03 Harley V-Rod

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Re: How to remove factory exhaust?

Post by EMS »

So, here is the issue with the torque on the exhaust flanges:

In addition to the problems I cited in the thread that Steve was linking to, there is one other consideration. Ever since the original asbestos gaskets went by the wayside, most (or almost all) people use copper crush gaskets.
These gaskets originate in the aircraft industry and the proper way to seat crush gaskets is not with torque, but with angle. Depending on the pitch of the fasteners, turning these translates to an axial movement - which is the figure you look for in a crush gasket. The procedure is to seat the gasket to no play and then turn the fasteners anywhere between 90° and 120°. This will compress the gasket and seal the connection. This is solid engineering and I know many here do not like it and rather fly by the seat of their pants, because this is how they have done it for 40 years. The big problem is the threads as I pointed out in the other post. It is very difficult to find the point where the gaskets seat with thread that are not clean and turn hard by hand. That's why a torque is your best compromise.

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