Honestly I don’t believe you can just drill a hole.
But if you are unconcerned with emissions I would gut the cat and remove the flappers. That would give you a bit more throaty sound.
My fishtail exhaust project
- Thread starter MilwDave
- Start date
But if you are unconcerned with emissions I would gut the cat and remove the flappers. That would give you a bit more throaty sound.
This past week or so I have been contemplating "drilling a few holes"..... trying to resist the temptation.... but it is probally futile (the attempt at resisting).
The plan is to buy the largest metal cutting hole saw that will fit through the fish tale oval exhaust exit end..... so probally 22mm or so..... weld it to a 600mm piece of rod and then do my best to drill (or more likely hack away at) the 4 hole "baffle" that is at the other end, hopefully creating on larger entry hole. I assume this baffle is there to brake up the airlow, causing "turbulance" so that the downstream wool/baffle is more effective. I was also going to block the 2 holes near the tail pipe.... so that wool was likely to have less of a pressure gradient across it as it would allow less flow then.
Anyway, what could possibly go wrong?
It’s not going to work. My suggestion is you apply your efforts to removing the catalytic converters and flappers from the head pipes.
Unless you are prepared to cut the mufflers open you aren’t going to be able to drill through anything to open up the fishtails.
Gr8adv
Well-known member
The 4 hole baffle was actually only three ‘thru’ holes as one was blocked off on both sets I did. I am not convinced of the value here even tho I did it. I used a very long extension for a drill bit that fit though the
What if I drill the wall of the oval opening of the fishtail exhaust at an angle?
The idea is to open 2 holes on either side, which essentially means there are now holes communicating air from outside the wool.
This is me thinking out loud. I did try it but broke the drill bit
Sometimes I know what I’m doing, and sometimes I think I know what I’m doing.
The idea is to open 2 holes on either side, which essentially means there are now holes communicating air from outside the wool.
This is me thinking out loud. I did try it but broke the drill bit
Sometimes I know what I’m doing, and sometimes I think I know what I’m doing.
kate_brett
Active member
Nothing has ever been achieved by holding back…….things can always be fixed. Then again, l’m not paying.
That metal inside the muffler is very heavy gauge and not straight. It is angled inside there.What if I drill the wall of the oval opening of the fishtail exhaust at an angle?
The idea is to open 2 holes on either side, which essentially means there are now holes communicating air from outside the wool.
This is me thinking out loud. I did try it but broke the drill bit
Sometimes I know what I’m doing, and sometimes I think I know what I’m doing.
Gr8adv
Well-known member
That is what makes it hard to get to the baffle.
Gr8adv
Well-known member
Good advice. You are learning more than anyone else knows. I hope people are listening and stop trying to find an easy way out as far as messing with the mufflers. Cats and flappers should be peoples first go.
Having messed with mine for some time and done some systematic volume testing there are not many choices.
The big DB changes are the mufflers. Doh! They even have that 90 degree bend in the pipe before it hits the baffle to accentuate the use of the muffler.
With your solution of bypassing you have pretty much created a fishtail version of the shorty volume wise. Good job!!! The fishies are iconic. But this is obviously why a baffle of some sort would be required (for me) as running without the muffler is a no go for this guy.
I was thinking of doing what you did except keeping the guts of the fishtail in place and just using an adjustable pipe that would essentially use all or part of the sound deadening based on length. Don’t ask how, idk. Lol.
Keep up the good work.
Last edited:
Gr8adv
Well-known member
No disrespect to anyone, but this has been preached for two+ years. How many times to do people have to hear this…
I am starting to sound like an old guy. Get off my damn lawn.
I just had a stock set of fishtails powdercoated.
Eventually I’ll post a video when I pair them with the gutted and welded headpipes.
Gr8adv
Well-known member
Ceramic?
Cerakote hi temp coating
As mentioned in the "what did I do today thread" I ran my bike a bit without the fish tails.... so on my scale of loud.... noisey Harley can be a 10, stock R18 with fish tales I'll give a 2, my R ninet with out flapper and db killer removed I give a 3.5, R18 without fish tails I give a 7.5..... anyway.... I"m looking for a 3.5 to 4 from my R18. We all talk exhaust sound etc but we are a quite diverse group.
Also, with my R ninet, when starting it near a group of people (so a side walk coffee place) I flick the switch to engage the flapper to keep it quiet.... as it has that horrible fast start up idle.
Also, with my R ninet, when starting it near a group of people (so a side walk coffee place) I flick the switch to engage the flapper to keep it quiet.... as it has that horrible fast start up idle.