Holes in Exhaust End

I propose to put several (say four or six) holes in the back of both exhaust pipes on my FI Intruder. I won't be knocking holes in the baffles, just the basic holes in the back plate, if that's what it's called. Just want a bit more noise, really and found my HH shorties too noisy. My question is, will the proposed drilled holes lead to any long-term damage, or will re-jetting or whatever be needed? Can I get away with just the drilling? Your opinion will be valued. Many thanks Oiler.

You can happily add holes to the exhaust end plate and even put a faster flowing exhaust on you FI model bike without any issues. 
The rules are as such for the FI intruders: You can modify or change pipes or modify or change the air filter but you can not modify/change pipes and air filter together without adding a FI injection module

Hope this is clear 

Thanks for this helpful info, and for moving my post. Hopefully other members will benefit from the info too. This info has made an old man very happy. As a grumpy old fart, happiness can be in short supply, the exception being of course whilst sitting on 'bike in traffic when a lady in very tight jeans walks by 

Have you drilled holes in your pipes and did it make them sound better?

Hi Oiler and Richard,

There are a few posts describing the mod you talk about and some U tube clips of guys doing it. yes it does change the exhaust note. For better... IMO no, just sounds like a louder sewing machine.

Your trike looks pretty awsome Richard, and the exhaust dosn't look stock. It appears to have been made into a 2 into 1.

GMAN Industries is producing a tuned 2-1 exhaust for the M50 which he says will be available around september.

Check out... https://www.youtube.com/watch?v=EdzyFLrdjv0&feature=player_detailpage#t=7

M

Hi Hogbos. I have, so far, put two holes per pipe. The sound seems greatly improved to me. i'm due my 4000 service, after which perhaps a few more holes. Will keep you posted. Thanks for your interest

Hi all,
I have put 4 13mm holes in each pipe (as per the YT vids) so what do you get for your labours??? a better sound.....and it does sound better, a few more bangs and pops on the over run (always makes me smile when my bikes do that) and tbh that's all you get, its not a performance mod but rather a sound mod. If you want more noise then the two baffle plate will need to be knocked out with a long bar and a lump hammer.
The vids on YT don't do the noise increase justice as the microphones on the vid camera's cant take its but it defo sounds better and more in tune with the way the bike looks.
Just my thoughts though guys and its a cheap mod with no detrimental effects.

Jim.

I'm tempted to say that bangs and pops on overrun is what life's all about. Not happened yet with two holes per pipe, maybe when I add a hole or two more

PS Could by absence of bangs & pops on overrun, be down to my bike being injected, is this delight something that only happens with carbs?

I have had injected bikes before which banged and popped on over run as its just un burnt fuel in the pipes, the better the flow the more you will hear it, it still happens with baffles in but its just deadened. 
I'd post some pics but I cant due to being a newbie here !!! got to wait a week or something like that.

Jim.

Great stuff Jimmyboy (and thanks) Will look forward. I'd willingly waste some fuel to get the sound.

question...
I read somewhere that holes in the back makes exhaust louder, holes in baffle makes it deeper.
is that true?
then i would first make holes in baffler to see what it sounds, and then made as many as I feel holes in the back?
thx

Marko, if it's stock exhaust then I'm not sure how you could make holes in the baffle without drilling through the back first...they're not removable (?)

As for overrun pops...sadly I only get one or two once in a while...even with my straight through pipes....shame :/

sorry
i dont know if i interpreted it wrong but i mean something like this:


anyway im looking for some cheap aftermarket exhaust or slip ons

I have eight half inch holes drilled in the end plates and knocked out the first baffle on the Trike it sounds good to me without changing exhaust. It would be real hard to change exhaust. I have the Fi2000 Pro fuel control also.

I'm telling a lie.... of course you can make holes inside.... you can drill through and then once the holes are inside, blank off the first holes.... :)
Now it's me probably not making much sense...

You will get very different types of sound and noise by modding the end plates and the internal baffle plates. I would beat a hole in the center first baffle first and do the second one if you feel the need to after drilling the rear plates with a 10 or 13mm drill. If you do decided to drill the end plates which may be enough for you on its own, then mark them first where you want the holes to be and punch them so that the drill stays in position.
Sorry no one can give you their definitive personal position with how it sounds as most will hear it in different ways as to what they want to get. Lots of different views on hear though so maybe you will like what they say. If you start by just drilling the end plates you will be able to get 2 small plates made to cover them up if that was later desired.

I completely removed the end plate and baffle and on the inside plate I have drilled three 1/2" holes and it sounds bloody fantastic

How did you remove back plate
Have you got any pics?

mare1411 wrote:

How did you remove back plate

Use a three inch hole saw Marko then a broom handle to snap the baffle off, youtube it, there's a few video's on there.

Good on you Richard, glad you like the sound.

Just before Richard says how he has done the end plate, I do know that it is possible to remove the end plates completely by attaching a circular hole saw attachment to your drill and doing it that way. Sorry I do not know sizes or anything else via this particular route but it will screw up a cheap chaep drill to do it that way

I did it the way of two hole saws cutting out the back disc and inserting a spare parrot perch I had into the baffle to wang it around to break the weld. For those of you who dont possess a parrot, a broom handle will suffice. Lol. Then in the next baffle plate I just drilled three 1/2" holes and hey presto, bobs yer uncle.
In the same manner as the video on youtube, I used a 1 1/2" hole saw first around the baffle, then a 2 5/8" hole saw to remove the whole back plate. Then insert parrot perch, broom handle if no parrot perch available, and just wang the baffles about till they snap the weld attachment. This itself results in a better sound but if you want to go further drill the holes in the 2nd baffle plate.
Also remember to borrow a drill and the hole saws off your brother in law as I did because it completely wrecks the drill and smashes the teeth of the hole saws.
No parrots were hurt in the making of this description.

haha..
thx.
all of you that removed baffels.. are you satisfied with sound?
would you put the exhaust back in the original state?

Once I'd finished I sprayed the inside of the pipe with high temp black paint to prevent corrosion.

Looks great, hole sawing out the and plates (1.5" and 3" I believe) and using a dowel or similar to remove the internal baffle pipe should give you a descent sound.
Nice mod, well executed.  

I began with one hole per pipe (in end-plate) progressed to two per pipe, which improved things noise-wise. Went to three, then four holes per pipe. Not a lot of diffference. It's now a matter of bashing a hole in the first baffle. This however, is quite beyond my limited (non-existent?) technical capabilities. I'll see if a pal can do this for me. In return of course, I could always oil his clutch cable. Take me back to my youth, and my CG125, when I actually oiled my own clutch cable, and have been mechanically 'resting' ever since !

Out of curiosity I wonder if the hole size could make much difference, maybe, maybe not. I know some drill them at 10mm and some at 12/13mm and I think they normaly do about 8? holes. I guess the size of the holes could add up to the same as another or more holes depending on how many there are. The good thing about punching a hole through the center is that it can't be seen

I believe my holes are 12mm each. Do you have any idea how far I have to push the pointed metal bar (I've borrowed) to bust the first baffles, but not (yet) the second ?

I think it's about a foot but you just rest the end of the pointed bar where it stops and there you go. I found it easier to bash through a very thin rod to make a core hole and then in with the big boy. Make sure you have some method of twisting it out - I drilled a hole in my bar and pushed a small screw driver in to get leverage for the 'extraction'. I noticed my exhaust note went much deeper with the middle hole. I then went on to do the next baffle which is not that much further on. Trouble is - if you don't like any of the stages, it's too late when it's done. knowing when to stop is the hard bit. Also MOT may be a problem. You can always have some back plates made up - I did. Have fun!

Diolch yn fawr

I have tried all the mods to the standard exhaust, for me the best is the stage 3 i.e baffles out with the 3" hole cutter !!!
Nice deep unmolested sound and a nice serenade of back fires and burbles on the over run !!!

Jim.

Back-fires and burbles are made in heaven.

oiler wrote:

Back-fires and burbles are made in heaven

Strange how some people hate it when they get it but I know of members on here and people I know else where that absolutelly love the affects and sound that this has on deceleration

If you completely close the throttle when you decelerate, it tends to burble less than if you leave it slightly open -tip! Burbling is the unburnt fuel suddenly igniting - starving the source reduces this, so I'm told. it happens just the same in stock pipes - it's just that you can't really hear it! Open pipes amplify the popping. Disabling/removing the pair valve can help. On my VN I stuck a marble up the hose - I still get some noise! On the Intruder I did not get as much even through the Highway Hawk Short Cuts.

Couldn't of said it better myself  John !!!

Jim.

A wise man has visited me this evening. Builds up bikes from old scrap/does all own servicing/improvements etc. Truly a spiritual being, living on another plane to someone who has only oiled his own clutch cable. This 'wise one' has suggested that possibly adding more holes to my backplate (six or even eight) could result in the engine running 'lean' (or was it 'rich'?) with eventual possible burning of valves. However, the poor sod has never owned a cruiser, just a Bonny, and has just rebuilt a 1200 Bandit from virtual scrap. Comments from this site would be welcomed by me, as to whether burnt valves is a likely/possible outcome ? Would re-mapping ever be worth the expense?
(here I would insert an emoticon to say 'thanks' but they seem to have disappeared. So Thanks    Oiler

My Intruder ran on debaffled pipes with the middle knocked out as well. When it went in for service the mechanic said the plugs were fine when I asked him to look. So I would not think a few holes would cause any harm.

Many thanks Bluesman. i'm off now to knock a few more holes. Oiler

Now have a total of six 12mm holes per pipe (can't get eight, didn't space 'em properly). Sounds better, and it could be my imagination, but I seem to have better acceleration too.

How do you remove baffles from stock exhaust? DO you just need to cut the front plate with a hole cutter and the rest slides out?

Nevermind...just found the topic that Dave did on it :] LINKY
If I could de-baffle mine in a way where the baffle can be fitted back in, I reckon I'd get deeped sound than Jardines and I could sell em to fund some other stuff...like apes... :]

Several days/rides on, and I'm convinced that my acceleration is greatly improved by the holes in my end-plates. Anyone got a view on this, or similar experience? Thanks

My opinion of this is that I think that it is highly unlikely that you are getting any actual real improvement in acceleration, I think it is probably that the riding experience has changed and you now think that, as you can hear what is going on rather than the usual silence we get from the stocker pipes. I know they set the bikes up so that they comform to ceartain criterea and will reach ceartain polution criterea but they would never reach those bench marks by having a bike that is running too a higher performance bench mark but then alowing one thing alone to restrict it back down. I think that what ever level they set the bike at for what ever their reasons were there would be changes needed to the exhaust and the filter and the fuel as a minimum before a noticeable increase was noticed one way or the other as they all rely on the other. They would be crazy to set the bike up in an increased power way and then alow on of the the things on its own to be restrictive as this would then not make very much sence but would also mean that they would be running slightly richer on the fuel side of things rather than slightly leaner which they are known for doing with these bikes

Thank you Captain. The technical explanation whilst gratefully received was way beyond my understanding. But in essence, the answer seems to be 'no'

Clive its a bit beyond me as well and may not be right, I have a little knowledge of these things but I am still learning from others so do not take what I say as fact its just my uneducated opinion. Some of the guys with a good knowledge of these things like Simbo and Mr Intruder and others may say I am wrong and give that explanation in either a much more simplified way or possabily a very complicated way, either way listen to the guys that do know more so than people like me

I agree with crash  Unless the exhaust is causing great restriction, drilling or removing the baffle won't increase power to give better acceleration, Sure sounds a lot better though 

Rubbish!

Louder = faster!!!    

Except in the morning! if you've got fussy neighbours 

I had holes in my pipes and liked them and would do the same again the good thing is that you feel like your more at one with the bike when you hear it, best free mod that can be done

I have the 8 1/2 inch hole and the first baffle punched out. It sounds good to me and the guys that I ride with say they like the way it sounds. One of the guys has a honda shadow trike with straight thru pipes. No one will ride behind him but me. So I guess I said that to say I have a pleasant sound without spending a lot of money to get something no one wants to ride with.