Reversing the "drill holes in muffler" mod...

[Shuriken]

The exhaust I have on my bike now has the chrome end plates removed and has the holes drilled in the muffler end.


I have gotten used to the mean growl but would like to revert back to a stock configuration. How do I do this?

• Rivet chrome end caps back to the muffler and JB Weld around the circumference of the chrome end cap?
• Rivet chrome end caps back to the muffler and metal weld around the circumference?
• Find some circular wafers or washers and weld them over the holes that were drilled, then rivet the end caps back in place?
• Other?

Looking for opinions here. Exhaust gas is corrosive and dirty. I could just rivet the end plates back on the bike as is but I don't want any exhaust leaks.

If any suggested repair options are $100 or more, I'm probably better of just looking for a set of non-drilled mufflers....

 

[one2dmax]

If you can weld the holes back up and grind them smooth (then paint), your stock chrome end caps will fit nicely back on and you'll be back to stock. The 85 mufflers were a 1 year only set since the next year they made the outlets smaller (they compensated in 86 by making the v-boost valve 1 mm larger).

Sean

 

[Shuriken]

If you can weld the holes back up and grind them smooth (then paint), your stock chrome end caps will fit nicely back on and you'll be back to stock. The 85 mufflers were a 1 year only set since the next year they made the outlets smaller (they compensated in 86 by making the v-boost valve 1 mm larger).

Sean

Thanks for the reply, Sean. That's what I was afraid of... weld first, grind later. If I just rivet the plates back on, how much exhaust will leak out around the end plate? I don't know if these are '85 muffs anyway.... what should the outlet diameter be on an 85?

 

[richwrench]

I reversed my drilled exhaust last night with no problems & no leaks. I had previously removed the end cap & drilled 1/2" holes between the rivet holes, then reinstalled the caps with a 5/16" nut as a spacer. It sounded good, but it's been running a little rich so I decided to go back to stock to see how it runs now. I was concerned that the exhaust might leak out a little from behind the caps, but surprisingly there's no leaks at all - totally stock again & runs great !

 

[Shuriken]

I reversed my drilled exhaust last night with no problems & no leaks. I had previously removed the end cap & drilled 1/2" holes between the rivet holes, then reinstalled the caps with a 5/16" nut as a spacer. It sounded good, but it's been running a little rich so I decided to go back to stock to see how it runs now. I was concerned that the exhaust might leak out a little from behind the caps, but surprisingly there's no leaks at all - totally stock again & runs great !

Thanks for the reply. So how did you do this reversal? Which of these steps did you perform?:

• Weld 1/2" holes shut
• Grind welds flush
• Rivet cap back into place

I still am unclear as to whether or not one has to plug the holes or not or if one can just rivet the caps back in place. I don't want exhaust leaking around the perimeter of the end cap.

 

[richwrench]

I just riveted the caps back on - they covered the holes nicely & it looks factory. No welding or grinding needed on mine, & there's no leaks around the perimeter. If there was a leak, it would be easy enough to drill the new rivets out & try another method - I guess it depends on where your holes are drilled & how large they are.

 

[Shuriken]

I just riveted the caps back on - they covered the holes nicely & it looks factory. No welding or grinding needed on mine, & there's no leaks around the perimeter. If there was a leak, it would be easy enough to drill the new rivets out & try another method - I guess it depends on where your holes are drilled & how large they are.

Thanks for the reply. That gives me some ideas....

 

[Shuriken]

I removed the end plates from my spare set of mufflers. Now I just need to figure out how to get them onto the set on the bike.

What kind of rivet gun do I need and what size/length of rivets?

 

[Shuriken]

I picked up some 1/8" chrome sheet metal screws and fastened the end caps back onto the mufflers. I wanted the ability to remove the plates at any time, which using screws provides. Sure enough, there is a bit of exhaust gas leak here and there, but I didn't bother to plug the existing holes. Not much of a concern to me right now but I can remove the plates if I want. Also, if you rivet the end caps and want to remove them at some point, you have to drill the rivets; when you drill the rivets, the rivet head on the inside of the muffler will fall off into your muffler and will rattle around.

All I gotta say is I have a new bike. Yes, I got used to that throaty mean growl that the "drilled muffler mod" produces, but I gotta say I like the "stock" sound better. First thing I noticed was that the engine has it's own sound now. But I can also hear the exhaust. So now I get to hear the engine wind up and can also hear the exhaust note. Plus, nobody is calling the cops on me when I run the bike around the neighborhood. If I want an impressive growl again, I just remove the plates.

Seems like there is a tad more bottom end but can't say for sure.

 

[Ctshooter]

When I reversed my exhaust mod I used a generous amount of high temp red rtv around the perimeter of the holes, then re-rivited the plates on and let it set up over night. No leaks and have been running them for a year now. I would imagine how well it seals is determined by what location the 1/2" holes were drilled. Good luck!

 

[xoe00]

When I reversed my exhaust mod I used a generous amount of high temp red rtv around the perimeter of the holes, then re-rivited the plates on and let it set up over night. No leaks and have been running them for a year now. I would imagine how well it seals is determined by what location the 1/2" holes were drilled. Good luck!

Why did you do the reversal, Ctshooter? (trying to decide if I want to even go there...)

 

[Shuriken]

I don't know why he did it but I did it for these reasons:

• WAY too loud; people call the cops, can't rev up the bike, can't ride it late at night.....
• Trying to get back to stock configuration so that I can do all of the tuning myself
• Trying to get a little more grunt back on the low end
• Because I don't trust anything that the POs did to this bike

I don't feel like I am compelled to wear ear plugs now, either.

Now, on the other hand, the drilled muffs mod DID start to grow on me. It did make the bike sound pretty bad news, but my particular VMax, in the condition it's in, and at the elevations I ride at, is not really all that fast. If I'm going to have a bike that's louder than a Nickelback song on a pair of 10" Kicker subs, it sure as hell better be really, really fast. Otherwise it's just obnoxiously loud! Just my opinion....

 

[richwrench]

Shuriken, I'm with you, I like the "stealth" mode. Plus it's easier to dial in the low end of the carbs. Until I can afford a Kerker 4-2-1 & a Morely airbox I'm stayin' stock.