Restoration adding modifications, butchery or?

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I wonder why he labeled it as a Triton when there is clearly not a single Norton part?
 
madass140 said:
well I've done the Old Britts mod already,...

... which wouldn't really stop you from putting Jim's breather on the crankcase if I'm not mistaken. The big advantage of the Jim/CNW version is the fact that it doesn't abuse those tiny holes connecting the timing case and the crankcase for breathing.



Tim
 
I knew a guy years ago named King Miller who restored bikes and cars for Jay Leno and others. He had a barn full of way cool stuff from an old Ner-a-Car, to old prewar Indians. One of the bikes he had was an old Harley JD which he had bought new in the 1930's I think. He had made so many additions over the years that he used to joke about the Johnny Cash song "One piece at a time" in reference to the bike. He did it his way with the mods of the period. I never thought of it as butchery.
He was a very colorful character who had an old stearman airplane and a private landing strip as well. I used to buy military parts from him.
I guess my feeling is that as long as it is still a Norton and not all buggered ( chopper) up with a Honda engine or another powertrain which clearly doesn't belong, it is up to you. On the subject of Choppers and bobbers, if I even see the words in the descriptions of listings on eBay I pass right by them. Why would a company spend thousands of dolars to make a great motorcycle only to have some ex con take a torch to it. Just sayin.
 
Tim,
It might pay if you made yourself familiar with the breathing on late 850s which is basically the "Combat mod" as recommended by Old Britts and, before Fred Eaton, by an under-cover service information from John Hudson that seems to never have left the factory.
We have modified endless 1972 crankcases to that condition- every other 750 in Germany seems to be "Combat" era one for some reason- and now they work. In our "family racer" Commando we have the same mod and, again, it simply works- and that is in racing, i.e. high revs, high loads, over about 15 seasons. Why this isn't good enough for a road bike, or what the disadvantages are in your opinion I do not know. I suspect they are purely theoretical. The holes in the t/s crankcase are not a problem in practice. The drive side crankcase is what falls apart in racing, being highly stressed, never the timing side.
Joe Seifert
 
illf8ed said:
batrider said:
Some feel the Old Britts mod to the Combat crankcase is butchery. Controversial. There is a danger that circulating chunks of metal could get sucked up right into the oil pump gears.
The stock '72 condition before the Old Britts mod has the potential to suck metal bits into the oil pump gears. That's the condition mine was in when I bought it before doing the oil pick up and breather mod.

Mine sucked up something too about 30 years ago and I sure wish this Forum was around back then because I probably would have split the cases and had a more informed look inside. I fished some metal out of the passageway to the sump (unrecognizable - maybe part of the tab) and replaced the oil pump. Also flushed the sump vigorously with solvent but nothing else came out. Bike had never missed a beat -- just found it when I decided to look at the pump. My oil plug never had the magnet but it is a good idea and on my list to get one.
 
madass140 said:
ok, I'll stop caling my project a restoration , its just another butchered rebuild, I can sleep easy now.

boyer analog would not go on my combat or EStart only std 850 or std 750

The term butchery has as much a financial connotation. Any of your mods that can be easily reversed with little cost should be OK and yet adds reliability or ease of function. The OB/INOA mod is not easily or cheaply reversed and while it might aid oil removal does not improve chunk filtering. To me the main goal of the OB/INOA case is to put money in their coffers = IMO cost/benefit is just not there. The mod that Windy or I do "IS" easily reversable, cheap to do and just as effective if not moreso.

I would NOT buy a 72/73 with the OB/INOA mod and would advise a friend against buying one if offered for sale.

your bike = your call
 
ZFD said:
It might pay if you made yourself familiar with the breathing on late 850s ...

Joe, I am perfectly familiar with that - it's just that Jim's setup is better IMHO. There will be pumping losses due to the connection holes and I have no doubt when Jim claims that he actually saw a partial vacuum only with his device. Granted the 850-OB-JH-breather is better than the foamy Combat breather-of-death but a light cold is also better than a severe pneumonia.


Tim
 
Tintin said:
The big advantage of the Jim/CNW version is the fact that it doesn't abuse those tiny holes connecting the timing case and the crankcase for breathing.

My understanding is that once the engine is revving, a GOOD reed valve, no matter where it's placed, will allow the crankcase pressure to remain relatively neutral and doesn't require a great amount of cross-sectional free area along it's path. The size of the exit hose may actually be the limiting factor at any speeds in the power band.

The "tiny holes" connecting the crankcase & timing chest are ample in cross sectional free area.
 
grandpaul said:
The "tiny holes" connecting the crankcase & timing chest are ample in cross sectional free area.

No, they aren't - and that's why I consider Jim's crankcase mounted Reed valve to be superior.


Tim
 
Tintin said:
No, they aren't - and that's why I consider Jim's crankcase mounted Reed valve to be superior.

Although I also consider Jim's breather to be superior to any other on the market, the simple reed on the timing chest is a huge improvement over the stock breather, is very easy to fit up in-situ, and cost just a few bucks.

Ample, and PROVEN effective by MANY happy Norton owners. It's hard to argue with sucess, yet some folks just insist on doing so...
 
once again it look's like you fail to read and understand Jim Comstoc's posting about what he has actually RESEARCHED and MEASURED crankcase pressure. once again YOU FAIL THIS CLASS

grandpaul said:
My understanding is that once the engine is revving, a GOOD reed valve, no matter where it's placed, will allow the crankcase pressure to remain relatively neutral and doesn't require a great amount of cross-sectional free area along it's path. The size of the exit hose may actually be the limiting factor at any speeds in the power band.

The "tiny holes" connecting the crankcase & timing chest are ample in cross sectional free area.
 
bill said:
once again

After I retire, I'm going to spend a couple of weeks rounding up all the posts from very happy Commando owners who have installed Mike's XS, mine, and other similar simple reed valves and reported back with nothing but happiness and praise for the simple modification and the immediate solution to thier oil dribbles. I can assure you that there are dozens on this very forum, and supposedly only a hundred or so Commandos represented as a relative cross-section on this same forum.

Pretty darned good proof, yet some people just won't take "yes" for an answer.
 
grandpaul said:
Pretty darned good proof, yet some people just won't take "yes" for an answer.

Did it ever occur to you that if something works well there might still be something that works better? And did you ever come across the saying that better is the enemy of good? :roll:

To me that is one of the fundamental failures of "pragmatist" trying to bash "theorisers".


Tim
 
below is the wording from a post from Jim about what he found with PROPER research NOT "well it seems to work " thinking . does the reed valve work no matter where it is put, yes BUT there is a better mouse trap and you keep professing the the old way of thinking as in ITS GOOD ENOUGH!!!


Jean,
Increasing the crankcase volume didn't increase the power. What made the power increase was larger holes reduced the pumping loss from moving air back and forth from the timing chest to the crankcase with each revolution.

Moving it in and out through 3 -1/2 inch holes took the most power.

Moving it in and out through 6- 3/4 inch holes took less power. Drilling more holes resulted in a fracture.

Plugging up all the holes except a single 1/4 inch hole for oil drain was by far the best. That way no power was wasted moving air in and out of the timing chest.

Reducing the volume of the crankcase by plugging the holes and moving the reed to the crankcase made a substantial difference in the crankcase depression. The most depression I ever got with the reed on the timing chest was 2 to 3 inches. After plugging the holes and moving the reed I was seeing peek readings of 8 inches. The amount of depression was dependent on rpm as the reeds would resonate at certain frequencies. I tried several different reed sets to find one that worked well in the normal operating range of a Norton. Jim

PS: I like that black cylinder head.
 
Tintin said:
Did it ever occur to you that if something works well there might still be something that works better? And did you ever come across the saying that better is the enemy of good? To me that is one of the fundamental failures of "pragmatist" trying to bash "theorisers".

Did you even read my reply, agreeing that Jim's is the best solution? (In other words, I agree that it works better).

I just fail to see the logic in arguing with a preponderance of the evidence that for 95% of the Commando owners, a simple reed valve on the backside of the timing case is an excellent solution.

Excellent is certainly better than good (the stock setup).
 
Tintin said:
And did you ever come across the saying that better is the enemy of good?

Actually, EVIL is the enemy of good. The other is just a saying, or else "better" would be evil.
 
Let's see...

Is all this "good vs. evil" discussion considered restoration, modification, or butchery of the Original Poster's question?

Sorry...
 
it depends what you are going to do with it, show it or ride it. if you are going to ride it then they need updating, as they should have been in the 70's
 
Hello to all. I have a much modified 1970 Fastback that runs well and does not leak oil. It has the older timed breather at the cam and I installed a "check valve type breather at the timing chest. The timing side has the additional holes but my only concern there is oil build up in the timing chest. I do not want any odd hydraulics going on :lol:

I also believe that improving mechanical equipment/bikes is important. Many "correct" show bikes are indeed never run and that to me is a waste. "Ride em, don't hide em" 8)

I like all of Jim's work and the concept of installing a transducer/o scope to really see what is going on inside these beasts! His latest breather is a no brainer for me.

This forum is the best and I enjoy the good insights from everyone. I do wish that everyone would consider the friendship and respect that we have for all those who ride before they post derogatory comments to "brothers" :lol:

Mike
 
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