'71 Commando, Rear Wheel Tilted? Offset (was: New Member, Introductions)

Background: '71 Commando Roadster. Bought it from a friend....ran like crap, handled like crap, everything is crap. Hopefully I can fix it. It came with 2 other bikes, a '73 Commando 850 that was seized up and a 1968 Honda CL350 (first year). First order of business was to restore the Honda and sell it. Mission accomplished. The proceeds from the sale paid for well over half of the purchase price of all 3 bikes...my conscience is clean.

I completely disassembled the '73 850 several months ago with the idea that some parts can be used on the '71 when I rebuild it and some parts can be sold. The '73 transmission cradle looked better than the '71 because it has the holes for the oil filter and the center stand holes look cleaner. The swingarm also looks more robust. Both swingarm spindles are in great shape, no drag, no play.

First picture....this is my methodology. Front end is tight, engine cases are in place (not tightened though), Z plates are tight and the trans cradle is tightened down.

The next 2 pictures are with the trans cradle and swingarm from the 850 installed. Picture 1 is the bike jacked up and no weight on the rear wheel. Picture 2 is the bike sitting on the rear wheel like a normal bike would sit.




The next series is the trans cradle and swingarm that came on the '71 (that came with it). Picture 1 is rear wheel off the ground, 2 is it sitting.




I realize that there may be parallax effect but in my opinion the '71 looks better. HOWEVER...there is still a pretty substantial offset of the wheel to the left. I've heard some say that is normal. That does not sound right....what say you?

Not normal, the wheel rim should be central in the frame. However, it is very common after 50 odd years of poor maintenance and rebuilding for such errors to develope.

hybridracer said:

Not normal, the wheel rim should be central in the frame. However, it is very common after 50 odd years of poor maintenance and rebuilding for such errors to develope.

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I have read in some places that the Commando rear wheel was laced up with the hub approximately 3/8" to the left. This would explain that fact that that center strip on the tire appear to be about 3/8" to the left of sight plane of the frame backbone.

IT looks like the swingarm is bent. If the front and rear iso mounts are level that should level the swingarm pivot( Front of the swingarm) and then check the level of the axle. I align and put the rear wheel /rim directly behind the front that is centered in the folks and not cocked to one side. You need to have true spokes on each wheel so it is not cocked by the spoking before you begin.

Banzaibob816 said:

I have read in some places that the Commando rear wheel was laced up with the hub approximately 3/8" to the left.

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Any offset was to bring it back in line with the centreline, the engine was over to the right.

kommando said:

the engine was over to the right.

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Left as you look from behind.

Mk3 swinging arm??

I'd be more concerened about the way the wheel leans to the left in your first two pics. My '73 *50 is like that when on the centrestand. Up to now, I've believed (and hoped) that it's just due to knackered Isolastic rubbers. I hope nothing's bent.

Here's what I know today:

This appears to be a common problem. The range of solutions appear to be "don't worry about it" to "throw money at it." At least on the '71 and other similar years/models the rear wheel apparently was laced up with about a 3/8" offset to the right side of the bike. This is not an uncommon feature for many bikes including some years of Harley/Italian, etc. I think that over the last 55 years, someone must've gotten in there and laced up a new rim perhaps. The spokes fit and are technically correct.....but they have a certain "imperfect" look about them.

The rear wheel was significantly out of true so what I did today was to put that offset into the wheel while truing it up. I'm pretty sure I've got it on the money.

The center tread line appears to be pretty close to the centerline of the frame backbone.....at least MUCH better than the pictures yesterday.


Also the "tilt" or slant is also a common lament. So far, many of the solutions have to do with installing new iso/rubber bits. As far as bent or damaged components, bends and damage show up elsewhere (cracked cases, bent forks, etc.) giving a general indication of a past accident. This bike DOES have that. If you'll notice the rear sub-frame loop, it was bent downwards but I straightened it. I didn't get it perfect but it will do for now, the seat hides that little bump. What is curious however is that yesterday the tilt was almost out of it (see yesterday's pictures). Today it is back...not as pronounced but still there. I am also leaving open the possibility that the wheel not being offset properly may have been hiding this.

Anyway it is measurable. If you look at the picture, the builder's square sits square on the surface of my lift. Measured at about 2/3 up the rear wheel, it is tilted (top to the left) allowing a gap of about 1/4"-3/16"......maybe 1º? Maybe less....but it is perceptible.




This is obviously a very small margin. The question would be: All other things being equal, have a lot of guys with these old Commandos been running their bikes with this kind of imperfection with any problems (I'm sure there are some of you guys out there). The next question would be, since it is such a small margin, what could be done to mitigate this?

My preference? I would like this problem gone. I personally don't think it will crash and kill me but I don't like imperfections and shortcuts. What say you?

Banzaibob816 said:

Here's what I know today:

This appears to be a common problem. The range of solutions appear to be "don't worry about it" to "throw money at it." At least on the '71 and other similar years/models the rear wheel apparently was laced up with about a 3/8" offset to the right side of the bike. This is not an uncommon feature for many bikes including some years of Harley/Italian, etc. I think that over the last 55 years, someone must've gotten in there and laced up a new rim perhaps. The spokes fit and are technically correct.....but they have a certain "imperfect" look about them.

The rear wheel was significantly out of true so what I did today was to put that offset into the wheel while truing it up. I'm pretty sure I've got it on the money.
View attachment 125572
The center tread line appears to be pretty close to the centerline of the frame backbone.....at least MUCH better than the pictures yesterday.


Also the "tilt" or slant is also a common lament. So far, many of the solutions have to do with installing new iso/rubber bits. As far as bent or damaged components, bends and damage show up elsewhere (cracked cases, bent forks, etc.) giving a general indication of a past accident. This bike DOES have that. If you'll notice the rear sub-frame loop, it was bent downwards but I straightened it. I didn't get it perfect but it will do for now, the seat hides that little bump. What is curious however is that yesterday the tilt was almost out of it (see yesterday's pictures). Today it is back...not as pronounced but still there. I am also leaving open the possibility that the wheel not being offset properly may have been hiding this.

Anyway it is measurable. If you look at the picture, the builder's square sits square on the surface of my lift. Measured at about 2/3 up the rear wheel, it is tilted (top to the left) allowing a gap of about 1/4"-3/16"......maybe 1º? Maybe less....but it is perceptible.

View attachment 125573View attachment 125574


This is obviously a very small margin. The question would be: All other things being equal, have a lot of guys with these old Commandos been running their bikes with this kind of imperfection with any problems (I'm sure there are some of you guys out there). The next question would be, since it is such a small margin, what could be done to mitigate this?

My preference? I would like this problem gone. I personally don't think it will crash and kill me but I don't like imperfections and shortcuts. What say you?

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I would consider the advice in post #4 now that you have the rim true with the hub. I doubt that many swing arms left the factory perfectly parallel

I don't think you have the engine and cradle well supported or have a complete engine assembly and a top motor mount on. TO draw any useful info, I would temporarily mount the cylinder and head and install the top mount. Then see how it looks. Grab or pry and try to twist the wheel so it is straight or plumb. ( If it will move), You need to be sure the bike stays still. and doesn't fall over

Then if you did what I suggested earlier, you could tell if the swing arm is bent or it is out of kilter for other reasons. If you don't get it corrected the sprocket will also be tilted and affect chain wear. If it is not diagnosed properly. Isolastics sagged, bent something , or?? Right now, Or, Van Halen right here and now, and I'm going back to the video, Bingo

The swingarm can be checked by inserting the pivot shaft and axle and placing all on a surface plate on four blocks . Make sure the axle is the same diameter on both ends - same with the pivot shaft . A glass table top or machined tablesaw table will do as a surface plate.

Carl H said:

I don't think you have the engine and cradle well supported or have a complete engine assembly and a top motor mount on. TO draw any useful info, I would temporarily mount the cylinder and head and install the top mount. Then see how it looks. Grab or pry and try to twist the wheel so it is straight or plumb. ( If it will move), You need to be sure the bike stays still. and doesn't fall over

Then if you did what I suggested earlier, you could tell if the swing arm is bent or it is out of kilter for other reasons. If you don't get it corrected the sprocket will also be tilted and affect chain wear. If it is not diagnosed properly. Isolastics sagged, bent something , or?? Right now, Or, Van Halen right here and now, and I'm going back to the video, Bingo

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The only thing that I could get done today was the wheel. Other than where it was welded/joined, I've got up and down/side to side runout at 0.010". Tomorrow's project will be that (those) swing arms.

To be honest, I had not yet considered the top motor mount yet...glad you mentioned that.

The backstory on the engine cases: Frame numbers and present engine numbers do not match. However, the engine cases shown in the pictures DO match. Evidently years ago the original engine threw a rod and punched a hole in the cases. I welded them up and am going to build the new engine with the repaired cases. Tomorrow I'm also going to start on piecing everything together and tightening it down for a better mock up.

So.... Today I was initially going to trying rig some sort of fixture that would determine swing arm straightness. I don't have a surfacing plate. I have a pretty robust workbench with 8 or 10 gauge steel plate for a surface that may work for that. However.....

Was able to take empty engine cases, cylinder and head and bolt them all pretty firmly to all mounting points to simulate finished conditions. I didn't torque to specs or try to adjust shim thickness, etc. I also made sure that my lift was at least laterally level. I took some more pictures.

These are the empty cases bolted solidly in place:



Next is the level and a longer view so I'm not looking at a parallax effect:


....and a closer view of the straight edge against the wheel:



So....I'm not seeing any space at the top of the tire. We know the lift is level....by all accounts the tire appears dead nuts perpendicular to the surface of the lift. The BIG QUESTION: Am I missing something? In the first picture of the rear end it still sort of looks off. This actually could be the rear frame loop from a previous crash, etc. making it look askance.

Since this looks pretty successful, I'm going to assume that at least for now that there is no immediate need to look at the swing arms. If this is indeed still off, I would guess that this changes the discussion from "how do I fix this?" to "how straight does this actually have to be?" Your opinions?

You can just put it on a flat stone countertop and use the pivot pin clamped to a v-block. Then see if the axle is parallel by measuring height at each side. Mine is bent and I can see it easily.
(There is an earlier thread on this by lcrken that does a much better job describing his procedure.)
Russ

batrider said:

You can just put it on a flat stone countertop and use the pivot pin clamped to a v-block. Then see if the axle is parallel by measuring height at each side. Mine is bent and I can see it easily.
(There is an earlier thread on this by lcrken that does a much better job describing his procedure.)
Russ

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I still have the swing arm from the 850....I'm definitely going to do it to that one. My big conundrum right now is that with everything bolted down and tightened up, it looks pretty darn close. Should I keep going or declare some semblance of victory?

I think my '72 swingarm has been bent since new and I used to worry about it all the time. I bought an 850 braced swingarm and it isn't straight either. I don't have a sturdy flat bench with holes or mandrels to manipulate it. Yours looks pretty good. I'd leave it and find more problems.
Someone could have a very busy business just straightening Norton swingarms and packing them so they don't re-bend. Hint hint.
Russ

Banzaibob816 said:

I still have the swing arm from the 850....I'm definitely going to do it to that one. My big conundrum right now is that with everything bolted down and tightened up, it looks pretty darn close. Should I keep going or declare some semblance of victory?

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I get the Bingo, but there are many right now moments B4 you get to declare Bingo yourself. B sure your square is square like a 3 4 5 triangle.

Norton did not put all those bolts in fer nothing.

The more I think about things, the smarter I get. And the wiser I become.

What I know today:

The 850 swingarm is bent...not more than an 1/8" but it is bent. The 750 swingarm appears to be straight.

Also un-noticed until yesterday, both front and rear isolastics from the 750 are worn and visibly appear to be off axis. The isolastics from the 850 appear to be in much better shape and are centered in their housings. I would love to replace both front and back with the Andover kits but right now the money is not there to do that. (Keep in mind the engine is going to require quite a bit of money.) I'm thinking about trying to fit the 850 isolastics on the bike and setting things up the old fashioned way. Yes? No?

Use the 850 head steady.