Bought original type balanced ext

Well, I know we've done this to death on other threads but I decided I wanted to personally experience the balanced exhaust that would have been on my 850 Commando originally. So I got the parts via ebay - pipes and cross connector - for 140 bucks. Pipes are like new, connector is in good condition but some discoloration. It'll be two months before I'm back in Mexico where the bike is located, but I'm looking forward to the "test." I may find, like everyone else, that they are too annoying and prone to cracking and end up going back to the 750 type exh but I just had to try it.

I'll be anticipating the big HP boost that Dunstall claimed the balanced pipes provided.

Anticipated failed threads in the head.

Let us know if you notice a difference in enging tone. I notice an obvious hollow box kind of precussion sound coming up from in front of tank when idling or at low speeds. I attribute this sound to the pipes until I can determine otherwise.

Will do!

As far as the heads - they were sleeved/threaded back before I bought the bike. Maybe they had to be because of the original crossover pipes!

Mike, I thought Dunstall claimed a little more torque but not more hp or am I wrong?

I believe that Norton added the crossover in 1973 in an effort to meet the new decibel restrictions in the US
testing going through second gear (raised for that reason) at 3500rpm?

I remember my 73 850 had the cross over and felt like it had more low down grunt than my 72 Combat,
and with only some 75 more cc's it had to come from the cross over

mike996 said:

I'll be anticipating the big HP boost that Dunstall claimed the balanced pipes provided.

Click to expand...

Pick up a copy of Morrison and Smiths' text on exhaust and intake design. Back in the day everybody who was anybody probably read it, including Dunstall. Now it's like reading Harry Potter meets Thomas Edison.

I think a possible explanation to why the pipes break the way they do is in how some of them are finished. The last set that I had break had the window cut into the header much smaller and miss-matched to the spigot that connects to the balance pipe. That section that sits out in the hot breeze on both sides compared to the adjoining metal has to be much hotter and have different thermal expansion action going on putting a stress on things. I found a source for that flexible tubing that Dunstall used. 1.5in ID minimum purchase 25ft.

I just had to replace my exhaust which was balanced to a non balanced set. The tone is much louder and higher pitched with a rapping sound on deceleration with is kinda cool but it is not as throaty as the balanced ones.
Mine lasted almost 40 yrs until the flaired end at the flange broke. I guess I was lucky. The balance tube was also left loose one one end which allowed it to flex a litted which may have allowed it to last so long. Never a exhaust leak or popping from it being left loose.
I just like the sound and look of the balanced pipes over the single ones but they're growing on me.

Balanced pipes have been fine on my bike for the 7 years I have owned it. I have made an effort to keep the nuts torqued down while hot to avoid stripped threads in the head. Bike has gobs of torque and runs great but I don't have anything to compare to so cannot comment on balanced pipes versus individual pipes.

About 47000mi on my MK3 with it's original balanced pipes. One exhaust nut loosened and dropped out of the head around 1977. Put it back with a screw driver and a stone and then a propper tightening of the day with a hammer and drift. About 15 yrs ago left header developed a 2" crack at the elbow. The best finessefull welder I ever met welded it up with no problems to this day. The chrome even flowed throughout the weld so it didn't even rust. When I've had to put them back on after removal for head or other work, I just tighten the big nut (now with a proper wrench) run the motor to get hot. tighten it again, ride the bike a bit, put some miles on it, and tighten it once more, done. I use anti-seize on the nuts and the threads in the head are original and perfect. I used to work at small brit shop and restored a couple of Commando's totaly and put a lot of new pipes on customer bikes. The non balanced sets seemed a bit harsh sounding compaired to the balanced. I can't speak for the torque plus or minus with either style. The balanced are a little harder to fit but the bell mouth of the header and corresponding hardware allow them to be a bit more flexible for adjustment. If I ever need a new set, balanced is what I would go with.

The universal effect of cross overs in twins to V8's, fairly close to head is increase in low power band torque via two exits for each exhaust pulse and a distinct but mild lowering of high freq note towards a softer deeper one yet no top end total hp help but nil subtraction off top end. A flex tube across the headers might stop fractures if the other methods don't. I got similar softer deeper note and more low down grunt response in Peel by the two into one Y pipes and definitely a help in high throttle off idle low rpm lugging w/o detonation or acceleration into chugging choking while climbing steeps loaded to the gilla on loose pebbles or grass where as my normal Combat with separate pipes tends to choke down stall or rev spin out so don't do that much on it no more.