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Quieter Exhaust?
Posted: Sat Oct 20, 2012 9:03 pm
by Tweety
Tweety was taken for a run to Melbourne return. 2 hours one way. Planning for our round Oz trip next winter I'm thinking the exhaust is just that little loud. great at 80kph but after 2 hours at 100-110 kph it is a wee bit noisy.
No room for more mufflers or even the smallest hot dog. No cat. has joining tube.
What I was wodnering is whether steel tubes could be palced inside the 4 tailpipes. they are 1 3/4" pipes. and if the inner diameter is say 1 inch would it quieten it down?
Posted: Sat Oct 20, 2012 9:46 pm
by El_Freddo
Don't even think about that until I've been for a ride
You should be able to get different mufflers that will reduce the noise. An exhaust shop worth their weight should know how to achieve this. It's not something you want to skimp on to get right.
Cheers
Bennie
Posted: Sat Oct 20, 2012 9:57 pm
by TOONGA
I just went through 18 pages of Tweetys thread on his
trike build to find the
exhaust pictures
Tweety wrote:
See because of the need shortly of a noise level test (for engineer) and besides I like a reasonably quiet exhaust. I left it to the exhaust guys to choose the muffler and they tole me these were the quietest of the several they tried on the ends of those straight out pipes.
Hmmmm quietest ones available at the time the exhaust was built.
Im thinking small baffles in a 3 inch pipe could be used, where the final pipes come off the exhausts. it would mean you would lose about a foot of the original up pipes but the baffles will quiet down the rumble.
TOONGA
Posted: Sun Oct 21, 2012 8:58 am
by steptoe
ear plugs man, people have gotta hear you coming for safetys sake, incase the yellow don't catch their eye soon after....
Posted: Sun Oct 21, 2012 9:39 am
by TOONGA
I was thinking this morning whilst having a coffee (it hurt heaps) and this is what I thought up.
Get two of these made for the journey, to go with the bigger mufflers. Then when you want to put the bike on show (or show off) put your original pipes back on. Surely there are smaller mufflers available, that will fit where your up pipes run.
or you get something like
this exhaust auger made that goes in the existing pipes either welded in or removable.
or even this little beauty (I may make something like that for PJ

)
stolen from this page
http://www.dansmc.com/Exhaust_4.htm
TOONGA
Posted: Sun Oct 21, 2012 2:29 pm
by Brumby Kid
The engine and exhaust are both new. Lets leave them for now.
How about a 4th or even 5th gear? That should keep the revs down.
Cheers Cam
Posted: Sun Oct 21, 2012 4:16 pm
by TOONGA
Posted: Sun Oct 21, 2012 11:33 pm
by Tweety
Thanks guys. Toonga. Thanks for your research. I think a baffle is the go.
Bennie, the mufflers were the quietest among all the ones that Midland Mufflers of Shepp had. they just pushed them on one by one till the quietest was found.
Steptoe, ear plugs. the cheapest option. actually I have a pair in my jacket...in one of the 20 pockets! lol. but yet another thing to take out put in when on tweety. Bikers know the rituals can become mundane. always forgetting one thing or another. will consider but prefer a baffle.
Cam, its an auto. a subaru 4 or 5 speed auto by subarugears is available but it is 140mm longer and would cause major re-engineering with mounts and chassis and swing arms which are fabricated eg not VW. This is because the fuel tank which is part of the monocogue frame is in the way. I';ve been through this a while back. and while the old 3 speed VW auto seems restrictive, it isnt now with the supercharger addition. EG Chev had a 2 speed "powerglide" auto box in their Belair model Users swear by it. The engine had so much torque the lack of gears wasnt an issue. Bottom line is - it simply isnt worth the effort in Tweety's case. and there is the K.I.S.S principle.
Posted: Sun Oct 21, 2012 11:40 pm
by woody.t
Brumby Kid wrote:The engine and exhaust are both new. Lets leave them for now.
How about a 4th or even 5th gear? That should keep the revs down.
Cheers Cam
dude how is a new gearbox a better solution in comparison to a different exhaust set-up?
Scrub this solution...
Posted: Mon Oct 22, 2012 1:58 am
by pitrack_1
Tweety wrote:and there is the K.I.S.S principle.
I know this is very, very simple, perhaps too simple for the application and stupid for the engine's design/control systems/complexity. But...
...Some coarse steel wool (coarse scourer type) in the exhaust pipes can be effective. The simple application this was done to was a VW dune buggy with straight through exhaust pipes. It was fixed in place just inside the pipe ends with fencing wire crossed across the ends. It was just enough to smooth the exhaust flow hitting the atmosphere. A typical farmer's solution, on an old-style motor but surprisingly effective and it was a flat four...
You can just see the wires + steel wool in the attached pic.
Posted: Mon Oct 22, 2012 8:33 am
by Tweety
Cam's view does have relevance in terms of "drum" Woody t. At 90 kph the noise is much more pleasant. I've seen this situation before with cars that dont have quite enough silencing.
Gee all the ways you guys quieten down your donks!!. I was also thinking about a large washer welded inside the exhaust tip with a one inch hole. The "problem" isnt so bad as to be drastic. Toongas idea of an extra muffler each side would be ideal but it isnt justified in terms of cost. Riding around Oz towing our small van next winter and I'm just knocking off potential issues that would irritate us and I think this is one I'd regret modifying beforehand.
Steel wool or a large washer or better still 4 baffles one in each pipe.

Posted: Mon Oct 22, 2012 9:13 am
by TOONGA
Simple baffle in each pipe should do it, the exhaust I PP'ed up was inspiration during a coffee frenzy. It would be the ultimate solution as it would kill all engine noise. (which Im sure you don't want)
I have some cheap steel wool floating around in my collection of bits and bods. I may have to try it in the exhaust, to see just how much reduction in noise there is.
I did once have an after market tip that acted as a silencer in the late 90's. it was on my old wagon, and one day I was out at the shops I drove in and the car was nice and quiet. I went to leave and someone had taken my tip. I had to laugh as it did nothing but stop noise and cost a whole 20 dollars.
TOONGA
Posted: Mon Oct 22, 2012 2:45 pm
by Tweety
let me know how that goes toonga.
Those tips used to be curled at the ends to a smaller diamter if they are the ones I'm thinking of.
A bloke has to be deprived to steel your tip!
Posted: Mon Oct 22, 2012 7:01 pm
by d_generate
We always used to use rolled up bird/chicken wire stuffed down the pipes if they were too noisy, after I had my new system put on my conversion 8yrs ago it sounded really tinny for a $!,800 exhaust but after about 2,000Kl it really quietened down when it coked up, now sounds superb
Remember steel wool can burn quite easily.
Posted: Mon Oct 22, 2012 7:18 pm
by Tweety
Think I've found the answer and $65 plus delivery from QE2 country.
what ya reckon guys?
http://www.ebay.com.au/itm/SHORT-4-EXHA ... vi-content
1.75" diamter 4" long baffles for trikes cars and M/cycles.
Posted: Mon Oct 22, 2012 8:38 pm
by TOONGA
They look like the go.
I must say it is funny how these baffles are made in the UK but not in Australia. Im sure there is a market with ricers when they get stickered.
TOONGA
Posted: Mon Oct 22, 2012 9:08 pm
by Tweety
update.
These are sold in pairs. 2 pairs with discount postage is less than $40 for the 4 .
worth a chance it'll fix the problem.
http://www.ebay.com.au/itm/150909852378 ... 1497.l2648
Posted: Mon Oct 22, 2012 9:57 pm
by TOONGA
Cheaper and the same thing what more can you want
A video of before without the baffles and a video after with the baffles
TOONGA
Posted: Mon Oct 22, 2012 9:59 pm
by Tweety
will do Toonga
nice when a fix is cheap. and hopefully successful.
Posted: Mon Oct 22, 2012 11:44 pm
by pitrack_1
Just about cheaper than steel wool...and much more professional. Worth a try, let us know how they go!
