New Member with 1970 Commando

pierodn · May 31, 2015

Hi Rivera,
dont forget to mount the shock absorver bottom chrome covers.
Ciao
Piero

rivera · May 31, 2015

Hi Piero!
I am sorry, I don´t have any!

cjandme · May 31, 2015

rivera said:
........If you haven´t dissasembled the bike yourself it is difficult to put it together..........The chain oiler is also blocked of on my bike. ( thanks for the hint, didn´t know were this pipe goes so far!).
Here is the assembly

./quote]
I must have missed your thread before, but I Ithink your making great progress. I have a '69 basket case in my garage back in Houston. I always did like the look of the halo ring headlight mount on the early bikes. My central oil tank in in far worse condition than yours unfortunately, (loads of rust on it from sitting outside before I got it) . Anyway , looking at your oil tank /battery tray/ air filter assembly, it makes me think of going a different route with mine, because the oil tank will be heating up the intake air before it goes into the carbs ( what were they thinking when they put this design together. Thanks for posting all your pictures and progress. Cj

Matt Spencer · Jun 1, 2015

what were they thinking when they put this design together

o0norton0o · Jun 1, 2015

I have a '70 roadster myself... just a few things you should do to it.

The early swingarm cradle tube only had a single fixing bolt for the swingarm shaft. They allow a lot of latteral slop in the swingarm. Some guys drill 2 holes in the swingarm cradle tube and weld 2 nuts onto the tube over the holes so they can thread a bolt into them and secure the cradle tube/pivot shaft connection solidly to eliminate play. I did the "kegler" modification to my bike which accomplishes the same thing, and looks like this...

It's 2 clamped collars that have a threaded hole over the hole you drill in the cradle tube to pin you pivot shaft in place. It improved my bike's handling exponentially. Early bikes really need this modification. Later bikes had cradle tubes which had threaded nuts welded in place in the area where the collars in the picture are located to accomplish the same thing.

The other thing the early bikes had is the camshaft breather, which works OK...., but I think it puts a lot of strain on the gaskets, joints, and seals of the bike. Adding a crankcase breather is easy for a '1970 model. I added one here...

I also drilled holes from the timing side into the crankcase to let the crankase pressure escape to the timing chest, and a hole down low behind the oil pump to let timing side oil drain toward the oil pickup in the crankcase... It's helped my bike stop leaking...

... And lastly. Do NOT have a key fob attached to your key if you have the key switch mounted in your left side cover. It chews the paint off as it dangles in the breeze as you drive, and you'll be forever repainting that side cover...

rivera · Jun 1, 2015

o0norton0o said:
I have a '70 roadster myself... just a few things you should do to it.

I keep to the original design with the top screw.
There is one end with a thread in the swing arm pivot shaft. Does this go to the left or right side?
Makes no sense when pointing towards the primary case.
I guess it is for pulling out the pin with a tool.
On the other hand the recessed side is better for filling the oil in.
So how should it be mounted?
I fitted mine to the right side with the threaded end.

There is still a lot to do until I can put a key in the into the switch on the left side panel...

o0norton0o · Jun 1, 2015

rivera said:
o0norton0o said:

I have a '70 roadster myself... just a few things you should do to it.

Click to expand...

I keep to the original design with the top screw.
.

If you are going to ride your bike rather than just enter it in shows as a restored "stock" commando, then the swingarm/cradle modification is a vast improvement to the bike's handling. In later nortons, the cradle was modified to have these threaded holes on the cradle tube as part of the stock set up.. Even Norton figured out that there was a lot of play between the cradle tube and the swingarm shaft and made the modification to improve handling... Feel free to ignore my suggestion or ask the forum members here who have early commandos if they agree... Good luck on your bike. It's looking great so far.

I believe the reverse bevel on the center pin goes toward the timing side so the oil can flow toward the hollow pin center. I also put a clear tube on the oil fitting and point it upward and have it filled with 140 wt oil so it automatically drains down into the swingarm... another modification ...

pierodn · Jun 2, 2015

o0norton0o said:
I have a '70 roadster myself... just a few things you should do to it.

The early swingarm cradle tube only had a single fixing bolt for the swingarm shaft. They allow a lot of latteral slop in the swingarm. Some guys drill 2 holes in the swingarm cradle tube and weld 2 nuts onto the tube over the holes so they can thread a bolt into them and secure the cradle tube/pivot shaft connection solidly to eliminate play. I did the "kegler" modification to my bike which accomplishes the same thing, and looks like this...

It's 2 clamped collars that have a threaded hole over the hole you drill in the cradle tube to pin you pivot shaft in place. It improved my bike's handling exponentially. Early bikes really need this modification. Later bikes had cradle tubes which had threaded nuts welded in place in the area where the collars in the picture are located to accomplish the same thing.

The other thing the early bikes had is the camshaft breather, which works OK...., but I think it puts a lot of strain on the gaskets, joints, and seals of the bike. Adding a crankcase breather is easy for a '1970 model. I added one here...

I also drilled holes from the timing side into the crankcase to let the crankase pressure escape to the timing chest, and a hole down low behind the oil pump to let timing side oil drain toward the oil pickup in the crankcase... It's helped my bike stop leaking...

... And lastly. Do NOT have a key fob attached to your key if you have the key switch mounted in your left side cover. It chews the paint off as it dangles in the breeze as you drive, and you'll be forever repainting that side cover...

Hi.
Good idea to mount another breather valve, but not all the 1970 right crankcase have the blanking plate.
I would not very happy to make holes on the shell.
Ciao
Piero

pete.v · Jun 2, 2015

pierodn said:
Hi.
Good idea to mount another breather valve, but not all the 1970 right crankcase have the blanking plate.
I would not very happy to make holes on the shell.
Ciao
Piero

It all depends on your comfort level.

rivera · Jun 2, 2015

OK, my Commando has a blanking plate. When I convert it, what will I do with the original breather opening ?

pete.v · Jun 2, 2015

rivera said:
OK, my Commando has a blanking plate. When I convert it, what will I do with the original breather opening ?

If you are speaking of the end of the cam timed breather, many simply plug it. Some leave it alone.

o0norton0o · Jun 2, 2015

I left mine intact because in my mind there's no disadvantage to having air and oil pushed in the direction of the camshaft bushing located at the port.

Here's some of the issues related to that... which I learned here from other people..
You need to drill at least one 3/8 inch sized hole from the timing chest into the crankcase. My bike already had a hole that size near the cam sprocket, and having 2 holes is what is recommended. so I just drilled 1 hole. (although, I left the cam breather intact, so I think I am getting help from both systems working together) I also drilled a 1/4 inch hole into the crankcase from the timing side down low behind the oil pump to let any accumulated oil on the timing side drain back towards the crankase, so it could be pumped out by the crankcase sump.

The old britts website shows where to drill the 3/8ths holes. I guessed on the lower oil return hole based on using the search function here and finding advice from Comnoz to add this oil return hole

I actually did this modification while my bike was assembled with my timing side cover off. I used a shopvac vacuum that I modified to suck up the chips while I drilled with a homemade inverse funnel tip that I made from a long funnel taped to the hose. Then I started the bike, ran it for a few minutes, and changed the oil twice to get any stray chips. I was glad I did that because there definately was some fine aluminum chips in the sump plug. My original blanking plate was dish shaped, so I ordered a flat one from old britts... here's the link:

http://www.oldbritts.com/n_c_case.html

I have to see if I have any pictures to post to make it more obvious

DogT · Jun 2, 2015

Then I've seen some articles where they blank out some of the holes, I saved this from Jim a while ago. I'm thinking about breaking mine down to re-seal the flanges and do the breather mods on my Apr '69 production model. Here's the note I have from Jim. Plug holes? I saved some pictures.

"The number and position of the holes varies from year to year. The earlier models may only have one hole to plug.
Regardless -you plug all the holes except the cylinder head drainback hole and drill a new drain hole next to the oil pump. Jim"

There were several threads about this and I'm still confused, except maybe about the hole down by the oil pump. I got Jim's sump breather several years ago, but we didn't know then the frame brace was in the way of it, so I sent it back.

rivera · Jun 2, 2015

The hose from the breather connects to the top oft the central oil tank(in my case)?
There is a pipe with a smaller diameter than the breather pipe coming out.

o0norton0o · Jun 2, 2015

the way I understand it from my research here is that the optimum situation would be to breath directly off the actual crankcase, BUT for us early model commando owners we don't have a bolt on option like Jim's sump plug breather or use of the combat breather location at the back of the crankcase. SO,... even though the timing side breather isn't as efficient as the crankcase style, it's still better than the stock breather which is marginal.

IF your choice is to use the timing side case to breath, then you need to add some holes to let air flow, you also need to add an oil return hole so oil that travels into the timing chest has a way to reach the crankcase sump... (I believe that was one of jim's comments about using the timing side breather method and it made sense to me, so I did it)

Here's my picture: I found it...

green arrow was the breather exit
red arrow by the cam sprocket is the existing hole to the crankcase
red arrow above the oil pump is the 3/8ths hole I drilled
Yellow arrow is the 1/4 inch hole I drilled down low behind the oil pump

The picture below shows where I drilled the hole for the oil return better than my other picture. it's the hole circled in red

DogT · Jun 2, 2015

Yeah, that second picture is from Jeandr, I have the original and in french the yellow lines at the top all say 'trous bouches' and it looks like they're all blanked shut. The bottom arrow says 'Nouveau drain de distribution', new drain hole, sort of. Of course that's a later model crank case too. I have some pictures from Jim where there's a lot of blanked off holes too. That's where it gets confusing to me.

Your first picture may be the best option for the pre-71 bikes as near as I can tell, especially if that's what Jim says.

o0norton0o · Jun 2, 2015

DogT said:
Yeah, that second picture is from Jeandr, I have the original and in french the yellow lines at the top all say 'trous bouches' and it looks like they're all blanked shut. The bottom arrow says 'Nouveau drain de distribution', new drain hole, sort of. Of course that's a later model crank case too. I have some pictures from Jim where there's a lot of blanked off holes too. That's where it gets confusing to me.

Your first picture may be the best option for the pre-71 bikes as near as I can tell, especially if that's what Jim says.

I wouldn't have a clue why anyone would blank shut air passages if they were using the timing chest as part of their breather modification. It seems to me that blanking them closed would be a modification for breathers that DONT include the timing chest volume in the route to the actual breather valve. Hopefully someone will correct me if I have that wrong, but that's what makes sense to me...

The only part of my modification that incorporated anything jim said, had to do with drilling an oil drain hole below the oil pump, because when you start pushing volumes of air (and oily mist) into the timing side, you don't have a means to pump oil that settles there out of the timing chest cavity. If oil built up in there, it was speculated that oil could be whipped into a froth by spinning of the timing gears and timing chain. Adding the hole down low lets the oil drain back to the crankase and get pumped out of the sump.

DogT · Jun 2, 2015

It may be that they blanked the holes for the engines that had the sump at the back of the engine. I'm just not clear on it at all. If I did anything I think I'd clear it with Jim, but your setup seems reasonable. I also think one has to be careful not to drill into one of the thick supports on the inside of the crank for the air breather hole. That's another reason to take the crank cases apart to do it, which I'd have to do to re-seal the flanges. I also don't have the cover plate where the old points went on the timing case like Piero showed.

Danno · Jun 3, 2015

I remember Jim spoke of drilling a timing chest drain/level hole lower than the factory did to reduce the amount of oil trapped in the case, but what is the purpose of the small hole behind the oil pump? Seems like that would allow almost all the oil to drain out and make for some very dry starts with regards to the timing chain.

o0norton0o · Jun 3, 2015

Danno said:
I remember Jim spoke of drilling a timing chest drain/level hole lower than the factory did to reduce the amount of oil trapped in the case, but what is the purpose of the small hole behind the oil pump? Seems like that would allow almost all the oil to drain out and make for some very dry starts with regards to the timing chain.

If that's what you deduce from a timing chest breather modification that has holes drilled into the crankcase to allow atomized oil and air to travel into the timing chest, then what do you think about crankcase breather modifications that plugs the timing chest holes??? Surely that modification doesn't oil anything in the timing chest since there's no provision for oiling, nor is there any atomized oil from the crankcase traveling to the timing chest.... ???

I drilled the 1/4 inch oil return hole because I didn't want the timing chest to fill with oil since there's no provision to scavange oil from the timing chest, so drilling the hole allows the oil to flow back to the crankcase... I've already stated that above btw.

Also, there's no doubt that it's a risky proposition to drill this on an assembled engine for a couple of reasons, and if I was taking my engine apart, modifying the crankcase to use a crankcase breather (like the combat breather) is a more efficient breather system, and a better choice.

Anyway, sorry for hijacking this thread. I actually didn't think the breather modification was as important as the cradle/swingarm shaft modification for early bikes. I lived with a timed breather and an oily bike for 40 years without it bothering me as much as the sloppy play in the swingarm did.

New Member with 1970 Commando

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