Replacing Header Pipes.

Bonzo

Bonzo

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If you were replacing the headers on an 850 Mk2 with peashooters, would you go with the flange type or the flared? I guess I'm asking, which are the easier to fit?

And would you stick with balanced or take the opportunity to go for unbalanced pipes?
 
Bonzo said:
If you were replacing the headers on an 850 Mk2 with peashooters, would you go with the flange type or the flared? I guess I'm asking, which are the easier to fit?

And would you stick with balanced or take the opportunity to go for unbalanced pipes?
Click to expand...
'headers' ? 🤔
The unbalanced down pipes are easier to fit and are surprisingly louder imo
Also they are known to produce a bit power
The downside is modern pattern ones rarely fit properly
The flared type give you more of a chance
I'm guessing Andover or RGM would be the best choice for getting accurately made pipes
 
baz said:
'headers' ? 🤔
The unbalanced down pipes are easier to fit and are surprisingly louder imo
Also they are known to produce a bit power
The downside is modern pattern ones rarely fit properly
The flared type give you more of a chance
I'm guessing Andover or RGM would be the best choice for getting accurately made pipes
Click to expand...

Headers. Header pipes.

Don't really want louder to be honest, although the balanced work out quite a bit more ££'s esp with the extra connectors & tube.

AN's 13.2046 has the same p/n for the Mk2A and the Mk3, but I thought the L/H Mk3 pipe was a different shape?
 
Bonzo said:
AN's 13.2046 has the same p/n for the Mk2A and the Mk3, but I thought the L/H Mk3 pipe was a different shape?
Click to expand...

According to the Mk2/2A parts supplement the LH pipe was the same part number as the Mk3 (065257) on Mk2A and apparently this exhaust was fitted to the Mk2/2A from 317312 according to Norton Triumph Service Release NTE 15/N3/77 December 1974 although it doesn't specifically mention Mk2A like the parts supplement does.
 
I recently compared some balanced pipes, you might find helpful

jimbo

Thread '850 Roadster balanced exhaust pipes examples'

What I have here, are four examples of cross over pipes
1. MK3 original :note it is missing the machined steel end piece , only a flared tube, they fit closer to the head than the non MK3's
2. Non MK3 original :note the machined end piece is brazed onto the pipe, makes for the nice clean look, with a decent cross pipe weld
3. Non MK3 replacement :note the machined end piece is now welded,, believed to be supplied by AN
4. Non MK3 Wassel aftermarket note: 15 yr old stock
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My early MK2a came to me in early 80's with balanced pipes but the headers were flanged, I could not get direct replacements so went with flared MK3 pipes and spherical seats. Never noticed the bigger gap on the primary side and liked the extra flexibility given by the flared ends onto the spherical seats.

As for the balanced pipes header welds splitting, just leave one balance pipe clamp loose and the headers will not be under strain.
 
Further to this I don't use silencer clamps
I use stainless pea shooters from RGMs and they are good sliding fit onto the downpipes
 
FYI, the flange and the flared type cannot be mixed as one comes out of the exhaust port farther out than the other, so the balance tube would not line up.
 
Is there any evidence that balanced produces less power than unbalanced on the same engine and silencer combination. I may be wrong, but I must admit that I have a hard time believing that.
 
ilikevelos said:
Is there any evidence that balanced produces less power than unbalanced on the same engine and silencer combination. I may be wrong, but I must admit that I have a hard time believing that.
Click to expand...
As far as I can remember, the balance pipe was all about noise reduction for the U.S. market. Nothing to do with power. It was used in conjunction with the plastic airbox, and a change in the (second?) gear ratio, as noise testing was mandated and measured at a certain RPM / speed as the motorcycle passed sound measuring apparatus.
 
No the balance pipe was introduced on the 850 Mk1 so before the plastic airbox and change in second gear ratio but it was done to reduce noise. The change to the black plastic air box, annular discharge silencers and second gear was originally made for the European market (850 Mk1A).
 
Last edited:
L.A.B. said:
No the balance pipe was introduced on the 850 Mk1 so before the plastic airbox and change in second gear ratio but it was done to reduce noise. The change to the black plastic air box, annular discharge silencers and second gear was originally made for the European market (850 Mk1A).
Click to expand...
Thanks @L.A.B. , I stand corrected.
 
On my 74 850 I have had the best luck with the EMGO header pipes. The problem I was having was clearance on the side stand lug on the frame.Both sides ended up fitting very nicely.
Mike
 

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