Guest EUGENE Posted July 21, 2003 Posted July 21, 2003 I keep reading of people drilling their standard mufflers. Can anyone help with a discription of how and where I go about doing mine? 02 v11 sport.
al_roethlisberger Posted July 21, 2003 Posted July 21, 2003 Two exhaust info sources: Forum Exhaust Mod FAQ Drilled Exhaust Discussion ...hope that helps
Janusz Posted July 21, 2003 Posted July 21, 2003 I am the one of a very few or maybe even the only one who actually PREFERS the clean and elegant looks of the factory cans so drilling idea was very appealing to me. The drilling process was already well discussed on this forum. It would be the best if you use a "search" function and find it; it is very detailed and includes pictures. Let me just add additional information. I found that if you just drill no matter how many holes and put the end cover back in place you just revert yourself back to stock sound and performance. Without the cover (you would never leave it like that so it was only for scientific purposes) and with a multitude of holes drilled (more then 10 on each side) the sound is very loud, seems almost unmuted and reminds a Harley with open pipes (yuck). The way originator of this idea (sorry, forgot who was it) dealt with this problem was cutting off the sticking section of a middle small diameter pipe and thus creating a large opening in the end cover. This not only left the middle pipe unsupported at the end but also would leave the exhaust still too loud and unrestricted IMO. I just installed the finishing plates back in place and started drilling small 1/4" holes directly in them. First one on each side - no, not enough. Then two - better but need some more. So I ended with three holes each. The sound is great, surely better and deeper then any aftermarket pipe I've heard so far. The performance DID NOT SUFFER for sure. One more observation: I left my bike completely stock for first 15,000 km. There is no question that a STOCK bike changes very significantly; the performance improves a lot and, more importantly for this topic, the sound of the exhaust surely deepens and grows in volume.I would never attempt to modify any new vehicle before it is fully broken in and for sure not the Guzzi being famous for its personality metamorphosis when fully broken in. I have now a Ferraci open box, K&N filter, Stucci X-over, drilled cans and Power Commander with weeks of tweaking (I love that thing and being able to play God with your bike). The bike rides like a rabid bat and sounds like no other bike does. And looks completely unmolested.
al_roethlisberger Posted July 21, 2003 Posted July 21, 2003 The way originator of this idea (sorry, forgot who was it) dealt with this problem was cutting off the sticking section of a middle small diameter pipe and thus creating a large opening in the end cover. This not only left the middle pipe unsupported at the end but also would leave the exhaust still too loud and unrestricted IMO. Just as a clarification, after drilling out the holes in the back plate, one does *not* cut out the rear support/weld for the inner muffler tube. The extended tube that normally peeks out of the rear "finishing plate/cover" is simply cut-off flush with it's weld as seen in the photos below. So this does not leave the inner tube/guts of the OEM Lafranconi mufflers unsupported as suggested above. Trimming off this extension allows the gasses and sound to now escape around and out of the now more open hole in the "finishing plate/cover". So no modification whatsoever is required for for the "finishing plate/cover" for the new increased sound and gasses to escape. It looks totally stock from the rear, unless an experienced eye is looking The photo below shows quite a "hodge-podge" of seemingly random holes, and I agree with Janus that this many holes are not really necessary. Probably no more than 9 or 10 holes drilled around the perimeter of the rear of the muffler are sufficient to add a little more bark and baritone to your exhaust without over-doing it. Hopefully it's clear in the photos. BTW, you are not alone Janus. I really liked the stock can's design and look as well. My only gripes were: - Heavy...very heavy - Fading fast, and turning purple.. even though my bike was low mileage and stored indoors - ...a bit restrictive, comparatively speaking - They also showed scratches/knicks very easily I think most folks found them attractive though, I know I did. al
Guest EUGENE Posted July 21, 2003 Posted July 21, 2003 thanks for the quick replys. you fellars are really on the ball.
Baldini Posted July 21, 2003 Posted July 21, 2003 On a completely standard bike, can this be done without changing anything in the fuelling side? Does it cause any mixture weakness or does the FI compensate? Thanks, KB, Wales
al_roethlisberger Posted July 21, 2003 Posted July 21, 2003 Most folks that have done this(alone) have reported no issues with leaving everything else stock. If you combine this with airbox, air-filter, x-over, etc... YMMV, and it would probably be in your best interest to have your dealer tweak the fuel mixture(if they have the MG/FIM software) or just get a PCIII. al
Mike Stewart Posted July 21, 2003 Posted July 21, 2003 Stock muffler 101, Here is a stock muffler sectioned from my 00 V11 Sport. It consist of three chambers in which different diameter tubes pass through. This is what creates the back pressure in the stock system. The lower large tube in the center section is the exhaust inlet. The exhaust comes in and runs toward the rear chamber, then is redirected back through the two small center tubes back to the front of the muffler. Once again after going through a baffle, the exhaust again flows back to the exhaust outlet. This is why the stock muffler gets so hot, the exhaust makes three passes through the muffler before it exits. The rear chamber is filled with some kind of metal packing so by drilling out the rear of the muffler it will create less back pressure along with more sound. When the packing burns away, one might have a very loud muffler. Mike
Mike Stewart Posted July 21, 2003 Posted July 21, 2003 Rear section with a perferated wall filled with steel packing. The tube on the right side is the outlet pipe. Mike
al_roethlisberger Posted July 22, 2003 Posted July 22, 2003 Thanks Mike, It's great to see one of these autopsied finally It looks about how I expected though, based on what external observations could be made, along with the results from drilling, etc. Although I guess one could now "core" one knowing this, it wouldn't be a minor task. al
Mike Stewart Posted July 22, 2003 Posted July 22, 2003 I guess I will weld her up now and sell it on ebay! any takers? Mike
Janusz Posted July 22, 2003 Posted July 22, 2003 My dealer has a collection of these after people replaced them with aftermarket cans. He offered me a pair for next to nothing. Good stuff.
dlaing Posted July 22, 2003 Posted July 22, 2003 I guess I will weld her up now and sell it on ebay! any takers? Mike I bid $9.99 plus shipping if you can leave the mid sectional out so that the only guts left are the rear guts and the front guts, and then weld it badk up, so that the exhaust will make a more direct trip out. Or does the center guts support the mounting studs? What would be really cool is if you convert it to a straight perforated tube packed in ss and fg wool. But that would be more work then worth the while. I told you before how a friend had made a tube out of perforated aluminum, well it finally broke down after a bit more than a year of riding. What a mess, riding behind him as he is blowing out chunks of fiberglass wool!
Guest jerroldt Posted January 4, 2005 Posted January 4, 2005 A great thread. I have thought about spending up to $1000 on TI mufflers but have never done it. My 04 Le Mans is a great bike but has lacked the sound of a true motorcyle. It has always sounded more like a turbine (while delivering great performance and speed) but without the sound of a sportbike. I spent 2 hours in the garage this evening cutting an inch from each inner pipe of the mufflers as suggested and drilling holes in the mufflers end plates. I went overboard in the drilling and made as many holes as possible without weakening the end plates. The result is that my bike now has a pleasant throaty sound (nothing like a Harley, since nothing else sounds like one) and I can still hear the sound of the valve train working at idle. I hope to see the spark plugs turn from black to brown as eventually some of the steel wool type material will get blown out of the holes in the mufflers and lean out the running of the bike. I think that the sound will also get better. If the spark plugs don't change from black to brown, I plan to open up the airbox etc.
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