1970 Commando

Seems I should just buy the bearing puller for the box job. What size tap did you use?
 
The one that fit. I have a cheap set I got off Alibaba, and I just pulled the one out that fit. I dont have the old bush anymore, so I cant measure. Ping @Madnorton on the forum and he can give you the ID of the kick start inner bush.
 
Just to confirm with those who have been there. I have read that a reed valve on the timing case blanking plate would be mostly useless unless larger holes were drilled into the crankcase. I have no intention of disassembling the engine to drill these holes.

Jim Comstock screw in breather it is then?
 
NPeteN said:
Just to confirm with those who have been there. I have read that a reed valve on the timing case blanking plate would be mostly useless unless larger holes were drilled into the crankcase. I have no intention of disassembling the engine to drill these holes.
Click to expand...
Not true in my experience of installing a dozen of them, and selling 3 dozen more. 100% satisfaction.

They DO NOT "fix" oil leaks. They DO stop minor weepage from being such a nuisance, and help significantly to de-puke your crankcase when/if your bike wet-sumps.
 
Any tips on removing the sprocket/mainshaft left hand thread nut? Thing is on there TIGHT.
Additionally, swingarm shaft will not budge. BFH bearing no fruit.
Other than that I have both inner and outer cases rebuilt, waiting on the sprocket nut to remove remaining gears to get at bearings.

BONUS PIC:
1970 Commando
 
Come on man!
Of course I removed the bolt! Hah
BFH and heat gun yielded fruit, just got the spindle out. I don't know why I keep asking questions, the answer always seems to be hammer, heat, repeat. Haha.

And yes, sprocket is locked with collar removed and I'm turning to the right. These nuts usually this stubborn?
 
NPeteN said:
Come on man!
Of course I removed the bolt! Hah
Click to expand...

Well, the question had to be asked. :)



NPeteN said:
And yes, sprocket is locked with collar removed and I'm turning to the right. These nuts usually this stubborn?
Click to expand...

Not always. You just have to devise a means of locking the sprocket (often by using the drive chain as mentioned in the manual).
 
instead of BF hammer you are allowed to use an impact gun , especially if you already have chain off ....
 
NPeteN said:
Jim Comstock screw in breather it is then?
Click to expand...

NO, Your bike has a frame member that blocks the Comstock sump breather from being used... As you know, I use a blanking plate breather (with 1 extra 3/8" drilling for air movement and a 3/16" drilling behind the oil pump for oil drainage) I also us the Jim Schmidt breather on the '70 model's camshaft breather port. So I have 2 breathers working together. IMO, the lack of a reed style breather was one the biggest flaws in any parallel twin. Having a pair of twin breathers, really eliminates the possibilities of oil leaks.

A few other things I wanted to mention to you, since I'm here....

The wings on the frame that hold the fuel tank often bust off because they weren't welded so great, Inspect them now and see how solid they are. Also when you go to mount the tank, there should be a rubber support bearing some of the tank weight between the tank's tunnel and the backbone of the bike frame. This way those wings don't bear the entire weight of the heavy fuel tank bouncing along as you ride. (yes, I know from having one break off prior to supporting the tank correctly...
 
i think there should be two rubber/foam pads .... there is on mine and really not sure on other years .... should show on parts list
 
o0norton0o said:
NO, Your bike has a frame member that blocks the Comstock sump breather from being used... As you know, I use a blanking plate breather (with 1 extra 3/8" drilling for air movement and a 3/16" drilling behind the oil pump for oil drainage) I also us the Jim Schmidt breather on the '70 model's camshaft breather port. So I have 2 breathers working together. IMO, the lack of a reed style breather was one the biggest flaws in any parallel twin. Having a pair of twin breathers, really eliminates the possibilities of oil leaks.

A few other things I wanted to mention to you, since I'm here....

The wings on the frame that hold the fuel tank often bust off because they weren't welded so great, Inspect them now and see how solid they are. Also when you go to mount the tank, there should be a rubber support bearing some of the tank weight between the tank's tunnel and the backbone of the bike frame. This way those wings don't bear the entire weight of the heavy fuel tank bouncing along as you ride. (yes, I know from having one break off prior to supporting the tank correctly...
Click to expand...

Frank- he makes one that screws into the existing Port on the left side where the existing breather is located as well, was referring to that one.
If you look at the beginning of this thread there is a bad weld on the right hand fin, definitely from a break that happened to a PO.
Currently investigating breather options, thinking maybe an in line flashback arrestor to catch can. Or the reed valve route you and others have pointed out.

I've got all the mounting foam on the fiber tank I've got here.

70 tank has a strap mount back correct??
 
I wasn't aware that Jim Comstock's breather screws into the camshaft port... I know that Jim Schmidt's breather does do that because I have one on my bike. You should check to be sure you have your info right regarding that.

My original 70 roadster tank was fiberglass and had the 2 buttons facing the seat that captured the loops of a rubber strap that wrapped the backbone of the bike. That held the rear of the tank in place. I replaced the leaky glass tank with a steel roadster tank that had a pair of threaded fixtures in the rear of the tank, similar to the front mounting fixtures. After that I switched to an interstate tank because 2.5 gallon tanks don't work for me since I don't put ethanol fuel in my bike.

Fiberglass tanks are temporary at best... If that's all you have for now, keep your eyes open for a decent metal tank.
 
You are correct! Got my Jim's mixed up, thanks for pointing that out.

Been looking for a steel tank, got my hands full at the moment. Really looking forward to assembly.
 
Nice, unlike me you'll avoid the 30 years of riding your bike as it snakes down the road, wondering why other people always bragged about commando handling. Somewhere along that line I concluded that it had to be bad bronze bushings, so I removed perfectly good ones and replaced them with no improvement. It never dawned on me that the single bolt swingarm tube was the cause til I saw the kegler clamps, read about them. Since then, I added cast wheels and new avon roadrider tires and I know how well a commando can handle...

I'm psyched for ya pete. The '70's are a little different here and there as we've discussed, but once you get it all together, you'll need to be hit with a brick to wipe the smile off your face after your first real ride... (if everything is right...)
 
NPeteN said:
Rear isolastics out, PB did it's job. Waiting on clutch puller tool to remove primary covers to instal verniers.
Still deciding on options with collars, choking up on the tube yielded no results. Don't want to grind away at it, may bring it to machine shop or something later today.

So, in my somewhat stalled out state I started investigation colors, this model was numbered a roadster but sold as an S and has flat blue original paint on the inside side covers. Bike had been painted purple in the late 70s, previous owner had the blue matched and bike repainted before I bought it from him.
Anyone seen a blue like this before? First photo (which appears a bit greenish) is believed to be original paint that was matched for the second photo.

1970 Commando


1970 Commando
Click to expand...
The backside of the side covers on my 70 Roadster had the same blue color. Mine was and is a Roman Purple. Maybe it is some sort of primer?
John in Texas
 
Just a quick recap.
Got the swingarm rebuilt with clamps in place.
Much stiffer than it was previously, feels good.
Outer and inner gearbox covers are rebuilt with new bushings and bearings, spring, pawl etc..
Layshaft bearing removed and replaced, old bearing was French.
Overall, not too difficult, knock on wood.

Still stuck on the sprocket mainshaft nut. Sprocket itself doesn't look TOO bad and the main bearing feels fine. Do I just skip em.....? Hmm.

Never expected to strip this thing to the frame so I'm a bit apprehensive about reassembly, mostly cable routing.

I'd like to to do something practical with the old chain oil spout other than just plugging it, ideas?
1970 Commando


Any idea what this thing is? Came loose with the bike.
1970 Commando


1970 Commando
 

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