What's the difference between these two? Was looking at complete exhaust from Commando Specialties for my 850.
I see that they don't have the balance pipe between the two headers. Does this make a differnce in tuning or idling or anything else?

I also don't see how they mount without the built in brackets that accept a bolt. Can anyone help me out with these questions before I decide if this is a wise purchase.

Many, many thanks.

That's a good question. I've been told that the exhausts with balance pipes are more dificult to install. I've also heard that the balance pipe helps performance. I've heard it hurts performance. Lots of automotive applications use a balance pipe for performance gains to control exhaust backpressure between two banks of cylinders.

I went with no balance pipe although my 1973 Roadster came with them.

The balance pipe was introduced on the 850 models purely to reduce noise levels. This subject has been discussed before, and the general consensus was that there is little, if any, performance benefit between either system.

Blue noser wrote:I also don't see how they mount without the built in brackets that accept a bolt. Can anyone help me out with these questions before I decide if this is a wise purchase.

The pipes are secured to the head by the finned exhaust rings and there are two lugs on the silencers/mufflers that bolt to plates which fit to the passenger footrest plates with metalastic bushes.

The lugs appear to have been positioned out of sight in the Commando Specialties photos, but their reflections can be seen, so they are there. Apart from those lugs there are no other fixing brackets. http://www.commandospecialties.com/

Ages ago , when my balanced oipes needed replacement , I asked myself the same question .
So I made a valve in the balance tube that I could open and close with a choke lever on the handlebar .
Riding at different speeds , but keeping the throttle in a fixed position , I opened and closed the valve .
If the balance pipe would have made any difference in power , I should have seen the bike accelerate or decellerate .
I felt NO difference whatso ever !
Only a little difference in sound : not quiter , not louder , just different .


If someone is interested to repeat this test , I'll be happy to send him the valve .

This has probably been conquered now but friends who had the balance tube seemed to have more pipe and flange problems. In theory it is a good idea but I'm not sure it worked well on Nortons.

I thought it depended on the type of silencers used, ie, reverse cone no balance pipe, non-reverse cone use balance pipe, that's how i've always understood it for my '73 850 Interstate,
Dave.

Hi,
You may or may not experience some sort of gain with the balanced pipe, BUT you certainly WILL have to look at it and compared to an unbalanced pipe it is UGLY. That is of course my humble opinion, others are welcome to form their own opinion no matter how wrong they are.
GB

daveparry wrote:I thought it depended on the type of silencers used, ie, reverse cone no balance pipe, non-reverse cone use balance pipe, that's how i've always understood it for my '73 850 Interstate,

All 850s originally had the balance pipe system, and for peashooters it doesn't seem to make any noticable difference to the power, (I changed to balanced pipes from unbalanced pipes and couldn't tell if there was any difference in power) however I believe the black cap Annular discharge silencers do need the balanced pipe system in order for them to breathe properly.

daveparry wrote:I thought it depended on the type of silencers used, ie, reverse cone no balance pipe, non-reverse cone use balance pipe, that's how i've always understood it for my '73 850 Interstate,
Dave.

That"s possible .
I should have added I did the tests with peashooters .

daveparry wrote:I thought it depended on the type of silencers used, ie, reverse cone no balance pipe, non-reverse cone use balance pipe, that's how i've always understood it for my '73 850 Interstate,

This is a bit of a myth. From the Norton Owner's Club website:

http://www.nortonownersclub.org/support ... -silencers

I quizzed Phil Radford at Fair Spares years ago about this, and he said no way. I bought a set of black cap silencers from him for my MKIII along with unbalanced pipes. I needed everything from front to back on the bike, wanted the black caps, and knew Phil wouldn't steer me wrong. I have no idea what the problem was with the bike mentioned on Mr. Patton's post. But I can say in my case, my MKIII has plenty of top-end and is deceptively fast, as a friend of mine with a Vincent Rapide found out. I have heard mention of the later black caps being different and possibly not as quiet as the early ones, so that may enter into some of this.

don. w

Thanks everybody for the helpfull replies. Especially L.A.B., he seems to know all and see all. I'm looking over my shoulder right now.

When I'm wrenching on my bike, I can hear him say, "no, you idiot, that's wrong!"

One thing to keep in mind is the balance pipes need to use split collars to install the nuts.This takes away approx. 1/8" of thread from the nuts which usually means sooner or later the ports are stripped. When I originally started to repair them many years ago they were 850's with the balance pipe.They replaced there exhausts then with single pipes without the balance.Nobody ever had any tuning or power issues.I would have to say of the hunreds of ports I have repaired 75% were 850 ports. Also use the norvil bronze nuts.They don't come loose.
Bruce

So what I'm picking up from the previous post is that my 850 has split collars under the exhaust nuts (which I found) but I also found two copper looking circular gaskets setting in the exhaust outlet (one so squashed that I could barely tell it was there). Should I leave out the collars during the reassembly so as to get more thread contact?

Diamondjet wrote:So what I'm picking up from the previous post is that my 850 has split collars under the exhaust nuts (which I found) but I also found two copper looking circular gaskets setting in the exhaust outlet (one so squashed that I could barely tell it was there). Should I leave out the collars during the reassembly so as to get more thread contact?

The collets should not be necessary if you're using the 850-style exhaust nuts on 750-style pipes. Check to make sure the nuts don't run out of thread without them. The copper washers seal the exhaust pipe to the head. Sometimes folks put two in to get a better seal - sometimes the old one is left in by mistake, and a new one put in on top of it.

The split collets are what holds the 850 pipes in the exhaust port. Because 850 pipes have the 'Y' for the balance pipe, the only way to install the exhaust nut was to use the collet. The downside of this is the fact that the 850 pipe and collet arrangement is deeper that the simple flange on a 750-style pipe, leaving fewer threads in the head available for the exhaust nut.

Another disadvantage of the balance pipe is cracking at the 'Y' due to vibration. I went through two left-hand pipes before going to the 750-style pipes. I did notice a few decibels increased sound when I changed to the unbalanced pipes.

The only positive thing I can say about the balance pipe is that I lost a few miles per gallon in fuel economy when I switched to 750 pipes. Commando exhaust has always been a trouble spot for me, and the cross over pipes just make it that much more aggrivating. Not a fun thing to deal with.