travel trials

Well another rally trip in the books. 1640 miles one way. My daughter Hannah got the long distance female rider award after riding the distance on my 1985 FJ1100.

I had a little problem on the way when the electrical system went dead at the motel in Green River Utah. I though it was just a bad fuse connection when I cleaned the green stuff off the fuse and everything worked again. Then about 40 miles later it did it again and left me setting along side of the highway. A little wire wiggling showed the problem was actually in the LI battery. It had a broken bus strap inside. A wedge beside the battery put pressure on the connection and lasted until I got to the rally and borrowed a torch for a more permanent repair.

Then about 350 miles from home on the return I had a little bigger problem when the RH exhaust thread let go. I had not done inserts when I installed the new Fullauto head around 13,000 miles ago thinking that, since my pipes are secured under the motor so there is very little load on the thread, it would last for some time. I should have known better. So "some time" amounted to 13,000 miles and the Norton finished the trip in the bed of my daughters truck. I rode the last 350 miles on the FJ.


There is a gland nut with packing to allow movement between the muffler and headpipe.



Here is a link to the head rebuild video I showed at the rally.

Looks like 5 threads holding it.
Maybe take some material off the down tube to give the head threads some more engagement? The down tube flange, It looked kind of thick.
You got home and that is important.
Cheers,
Thomas

everyone, get your heads over to Jim now!!. he'll be doing a run of exhaust threads very soon

CanukNortonNut said:

Looks like 5 threads holding it.
Maybe take some material off the down tube to give the head threads some more engagement? The down tube flange, It looked kind of thick.
You got home and that is important.
Cheers,
Thomas

Click to expand...

The flange is a little thicker than a single wall pipe but considerably thinner than the conical washer and collets used with a crossover exhaust.

If you look at the threads in the head you will see they are pulled all the way down to about 1/8th inch from the gasket. The outermost threads are not stuck to the nut.

They are the same flanges that were used for many years with the inserts in my old head and I am sure they will work fine after I install inserts in the new head.

madass140 said:

everyone, get your heads over to Jim now!!. he'll be doing a run of exhaust threads very soon

Click to expand...

I already do exhaust inserts in at least a couple heads a week, but yeah, send them on over...

The flange is a little thicker than a single wall pipe but considerably thinner than the conical washer and collets used with a crossover exhaust.

But you are not using the collets and crossover exhaust system?
Why did it fail?
My humble response
CNN

"I already do exhaust inserts in at least a couple heads a week, but yeah, send them on over"
yes Jim, you already have done one for me. Maybe this could of been a good addition in the Fullauto
head production, along with inserts for the 3 x 3/8" studs

CanukNortonNut said:

The flange is a little thicker than a single wall pipe but considerably thinner than the conical washer and collets used with a crossover exhaust.

But you are not using the collets and crossover exhaust system?
Why did it fail?
My humble response
CNN

Click to expand...

No crossover type collets or washers.

I had checked the nuts when I prepped the bike for the trip. They had never come loose.

The nut could not have unscrewed as it was retained to the pipe flange with 2 radial socket head setscrews, but it obviously wore the threads enough due to expansion and contraction that it began to move a little with the exhaust pulses. Once it started moving it would have taken the threads out pretty quickly.

It had been ~250 miles since I had gassed up so it obviously went from not noticeable to wiped out in that amount of miles. I make a habit of starting the bike and listening to it at each gas stop before I put in my earplugs.

Since I was wearing earplugs, I did not hear it until the nut and pipe [which were still clamped together with the setscrews] were blown completely out of the hole.

madass140 said:

"I already do exhaust inserts in at least a couple heads a week, but yeah, send them on over"
yes Jim, you already have done one for me. Maybe this could of been a good addition in the Fullauto
head production, along with inserts for the 3 x 3/8" studs

Click to expand...

Yes, it was mentioned.

oh well history now.

That is the third known failure in 230 heads, including my own. I was planning bronze inserts at some stage, but, it all adds up, and, as you all know, something flashy to hang off your bike is much more important than an improvement to reliability that can't be seen.

I wouldnt say a failure Ken . if the threads are good from the start then its something else. If new threads are
looked after then they should last a lifetime. not sure what happened to Jim's here

Bummer. And I said no to inserts when you did my FA head...

"There is a gland nut with packing to allow movement between the muffler and headpipe."

I'm trying to accomplish the same thing by backing off the stock clamp just enough to allow such movement. Will that not work?


Sorry to hear the bike didn't make it all the way, Jim, but that's a heck of a trip. Congrats on making it as far as you did! So close!

Had the inserts installed in the head Jim recently did for me, just have to send it out for combustion chamber coating, but I'm really looking forward to getting this puppy installed in the new engine

The trip was still a great adventure! Back in the late 60's/early 70's when we rode these things around I never saw an exhaust thread failure. Of course the heads were off 2 or 3 times a season for some other problem.....

acadian said:

Had the inserts installed in the head Jim recently did for me, just have to send it out for combustion chamber coating, but I'm really looking forward to getting this puppy installed in the new engine

Click to expand...

Hope you know what you’re doing... I had my combustion chamber ceramic coated and chunks came off and took the bore with it !

Atlas Commando said:

The trip was still a great adventure! Back in the late 60's/early 70's when we rode these things around I never saw an exhaust thread failure. Of course the heads were off 2 or 3 times a season for some other problem.....

Click to expand...

My first Norton failed in the 70's. It was an N15 and the nut came loose on a little ride out of town. I didn't have a real wrench with me so just tightened it with pliers as best I could. About the 3rd or 4th time I stopped to tighten it there was nothing left of the threads.
I sent the head out to Schultz tooling who cut oversized threads in the head and sold me a pair of oversized stainless nuts. He did this to a lot of Norton heads through the 70's and 80's.
I would say that around 30% of the heads I repair have had at least one previous repair using aluminum inserts. Comnoz

Everyone has different experience, but those exhaust nuts have been causing trouble for a long time.
A local machinist here, Chris Timberely, set up to do Commando inserts back in the late 70s, so the bikes were quite new then.
He still does a few every year, less and less. He commented to me that " not many are really riding very far on them these days"
Probably some truth in that.

I have to admit that it was nice to pack up the modern bike for a 4 thousand km trip and not worry about bringing tools and spare parts...
On the other hand a too short wiring harness did act up, so even a mass produced modern is not immune to trouble.
I refuse to carry spares and tools for either of the modern Triumphs. If there is an issue on those bikes, I doubt it can be sorted roadside anyway.

Still, its more fun on the old stuff if you go with like minded people.
If you tour with riders who are on modern bikes, best ride a modern.
They don't understand the occasional need for " roadside maintenance"

Hey Jim, it was great to see you at the Elma rally and share stories around the propane fire ring.
Strange you would lose the threads on the head. I always thought the threads pound out because people rode the bikes with the nuts loose, which clearly isn't the case here. Makes one wonder what caused the failure.

Stephen Hill