Muffler noise level

Yes, the 850 exhaust pipes would fit a 750, but how much quieter is subjective. Probably not worth the trouble of extra exhaust gaskets to seal with 850 exhaust nuts or use 750 nuts. Then there's getting the balance tube not to leak. Supposed to balance out the exhaust pulses and maybe a little better midrange.
I've had both 850 & 750's with Dunstall "silencers" and didn't notice much difference in noise level, if any. You would only be able to buy Dunstall replicas now and there is just flimsy fiberglass inside that won't last very long.
I would just pick your price point and buy a pair of pea shooters if that's the look you want. You're never going to be Harley loud with a Norton unless revving it to redline in every gear.
 
Deckard said:
Yes, the 850 exhaust pipes would fit a 750, but how much quieter is subjective. Probably not worth the trouble of extra exhaust gaskets to seal with 850 exhaust nuts or use 750 nuts. Then there's getting the balance tube not to leak. Supposed to balance out the exhaust pulses and maybe a little better midrange.
I've had both 850 & 750's with Dunstall "silencers" and didn't notice much difference in noise level, if any. You would only be able to buy Dunstall replicas now and there is just flimsy fiberglass inside that won't last very long.
I would just pick your price point and buy a pair of pea shooters if that's the look you want. You're never going to be Harley loud with a Norton unless revving it to redline in every gear.
Click to expand...
I definitely noticed a drop in noise level when I fitted down pipes with a balance pipe to my 750
 
...and I love the bark of the pea shooters


Which, is only a small percentage of what the big barkers emit, so not even raise an eyebrow nowadays.
8A3A8928-7985-4ED3-9D0B-CFD1267EC587.jpeg
 
Last edited:
Back in the 80's, living in Philly, I used to love blasting down the street with open pipes setting off all the car alarms. Always kept the neighbors in check.
 
Anyone bought and care to comment on NZ Viking Header/Peashooter combo?
Can't really see the point in their "big bore" (1 5/8") system?
Cheers
 
robs ss said:
Anyone bought and care to comment on NZ Viking Header/Peashooter combo?
Can't really see the point in their "big bore" (1 5/8") system?
Cheers
Click to expand...
Some years ago I had Viking pipes on my T160 and the quality was top drawer.

Personally, I would never fit big bore pipes to a Commando unless it had had serious work and actually needed them. I tried some RGM ones on the dyno and (as predicted by Comnoz) they were a definite de-tune compared to the stock unbalanced pipes, and that was on an 850 with a JS cam, raised CR, etc.
 
Last edited:
quawk said:
Am looking over the peashooter mufflers offered by Andover Norton and all 3 styles they offer for the '73 roadster application say they have sound deadening. Can someone tell if they use something like the fiberglass packing that used to be used on all the "glass pak" mufflers of old? Or are they just perforated, slotted, or louverd interal pipe/baffle?
Click to expand...
Quack,
I purchased a set of silencers from AN that were supposed to be the quieter set. They fit nicely but in all honesty I could not hear any noise difference.As Greg Marsh said, the ones from EMGO that I have installed on other bikes fit perfectly and would recommend them.
Mike
 
robs ss said:
Anyone bought and care to comment on NZ Viking Header/Peashooter combo?
Can't really see the point in their "big bore" (1 5/8") system?
Cheers
Click to expand...
I had a big bore two into one system on my 750 for a short time
It was the worst system ever
It just made the bike feel flat and it refused to rev out in top ,it wouldn't go over 90 mph
I remember playing with the jetting and at the time it had twin amals and a k&n filter
I changed to separate down pipes and pea shooters and the bike woke up
 
What was the outside diameter of the original header pipes on the '73 roadster/hi-rider? I've seen some discrepancies as to some of them being 1 3/8" or 1 1/2", with, in some cases adapters being used to fit one to another. I want to get the correct diameter of header pipes and muffler inlets to not use any sort of adapter.
 
I have this little Suzuki GN400 for bringing along in the campervan when on holiday. Nice and light, but the muffler is, well, a bit too restrictive, too civilised?
So I thought, why not swap it for a peashooter.
I tested 3 different types I had lying around, see below.
In the picture, the orange tapes show the extent of the fluted part of the inner tube.
Quietest was the Campbell at the bottom, type Z601, logo near the front, weight 2455 grams.
Reasonably quiet was an unknow type (maybe original?), weight 1838 grams.
Loudest was another Campbell, no type number, logo near the end, seamless outer shell, weight 2062 grams.
My favorit is the Campbell Z601, although it sure is a lot louder than the original GN400 muffler.

Muffler noise level
 
slimslowslider said:
I have this little Suzuki GN400 for bringing along in the campervan when on holiday. Nice and light, but the muffler is, well, a bit too restrictive, too civilised?
So I thought, why not swap it for a peashooter.
I tested 3 different types I had lying around, see below.
In the picture, the orange tapes show the extent of the fluted part of the inner tube.
Quietest was the Campbell at the bottom, type Z601, logo near the front, weight 2455 grams.
Reasonably quiet was an unknow type (maybe original?), weight 1838 grams.
Loudest was another Campbell, no type number, logo near the end, seamless outer shell, weight 2062 grams.
My favorit is the Campbell Z601, although it sure is a lot louder than the original GN400 muffler.

View attachment 114041
Click to expand...
Fun bikes those GN 400,s I had one given to me years ago
It had a high compression wiseco piston and a joy engineering cam
I had a commando pea shooters on mine but it was empty
And I cut it in the middle to crank it round the shock
It ran really well and I often wonder what became of it
As the bloke that bought it was around 9st and he couldn't start it !!!
 
quawk said:
Will be replacing the exhaust system on my bike. Will be removing the turnout type mufflers and head pipes that the PO had installed on my Hi-Rider, as I mentioned in previous posts. Want to install "peashooter"mufflers as most guys call them. There are a number of sources for these mufflers and would like recommendations or suggestions from others about sources. Do some makers offer some decent noise reduction as opposed to straight through design? Would rather have some that are a little more quiet as opposed to louder. Also suggestions on head pipes, as I'll be needing to install ones with the up bend ahead of the mufflers as those currently on my bike are straight with no bend. Any advice would be appreciated.
Click to expand...
good morning
just went thru this process, most vendors only are aware of the loud ones
quawk said:
Will be replacing the exhaust system on my bike. Will be removing the turnout type mufflers and head pipes that the PO had installed on my Hi-Rider, as I mentioned in previous posts. Want to install "peashooter"mufflers as most guys call them. There are a number of sources for these mufflers and would like recommendations or suggestions from others about sources. Do some makers offer some decent noise reduction as opposed to straight through design? Would rather have some that are a little more quiet as opposed to louder. Also suggestions on head pipes, as I'll be needing to install ones with the up bend ahead of the mufflers as those currently on my bike are straight with no bend. Any advice would be appreciated.
Click to expand...
Morning.....Just went thru this process
most vendors only are familiar w the loud ones
Andover Norton offers one that is noticeably quieter: 06.1978/X/SNL
make sure these #'s are exact
Super pleased w the result
 
You can ride with whatever noise level you can stand and over the years they will get quieter. That said, I can still hear the straight pipe on my G80 Matchless just fine. Wife? Not so much.

Balance pipe on my MKIII did improve mid range but not noise level IIRC. Leave one balance-pipe clamp loose on one end to accommodate temperature expansion and contraction, and use lots of anti-sieze on the joints then the pipes won't crack at the weld for the balance pipe. My theory that it's not the vibration but the expansion that cracks the welds seems to have been born out as mine haven't cracked these last 20 years. And that's the way I assembled many customer's bikes back in the day and didn't have come-backs.

The nicest sounding pea shooters I remember were on a Commando with high pipes. Those had been cut apart and the baffles taken out altogether, re-welded and re-chromed. Nice hollow sound I could hear well when following behind. Not quiet however.
 
ludwig said:
You could make doors in the muffler and stuff it with damping material.
Invisible when on the bike :

Muffler noise level
Click to expand...
I realize you could take such measures, but I'm not going to go to that extent. Was just asking for comments on what available new mufflers were quieter than others. Not going to pay the going price for a pair of mufflers just to cut them open and Frankenstein them.
 
Id throw early Domi, P.R., foist fastback style Things onit . tho they can foul the footrest hangers , P.R. upswept with P.R. footrest / muffle alloy thingamy arms .

Muffler noise level


WHILE WER'RE AT IT . The non Protruding sidestand bracket allows the tighter closer fit
PR headers , wot go up inside the chaincase lips . So you can go twice as fast .
Theres kinked top & flared top , I think I had kinked largwer bore . But never usedem .

Theyre the MUDFFLER , with good NORTON tradition up to the elbows . AND authentic ' Commando ' .
 
Hmmm - I have a road bike.
Would I prefer a safely functioning sidestand or extra LH cornering clearance and hotter primary cases?
To take advantage of that I'd of coarse also have to toss the centrestand.
What a difficult choice!
Bugger! I hate dilemmas!
 
You must log in or register to reply here.
Back
Top