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Hmmm. I could buy a new one from Norvil for 1200$

You don't think a good frame guy could cut out the bottom rails and weld in new sections? I guess finding a nused frame might be cheaper?

example of ebay not being too terrible except you don't list where you are so if out of the US it could be expensive.

http://cgi.ebay.com/ebaymotors/VINT...1621814QQptZMotorcyclesQ5fPartsQ5fAccessories

I don't know how fast you plan to have your project done. But it looks to me like you have plenty to keep busy on before you start bolting stuff to the frame. I would talk to a couple of frame guys about it. Keep your eye out for another at a good price. And in the meantime get stuff ready to bolt on. If you move at the same speed I do that gives you lots of time to look around!

I have been trying to visualize what would happen if that tube cracked while you were riding. I am not sure it would be that big a deal as long as you didn't keep riding it that way. Anybody have practical experience with that?

Russ

Old Britts has used frames for reasonable prices sometimes. You can trust them to tell you the shape it's in. Seems to me they are about $750. Keep your options open.

Dave
69S

britbike220 said:

you don't list where you are so if out of the US it could be expensive.

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Ooops. Thought I set that. Fixed it (I'm in Silver Spring, MD right next to DC)

rvich said:

But it looks to me like you have plenty to keep busy on before you start bolting stuff to the frame.

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Agreed - I'll look around and see what comes up.

That eBay frame is a good price - but would an 850 motor / cradle / swingarm work? Looks to already have had welding done at the head + it'll prob need more gusseting at the back, no?

It was very good of the previous owner to share that photo with you. I guess. The funny (as in ironic) thing is that had you not seen the photo you may very well have never known. Tubing is very strong for its weight. I am not an engineer but I know from practicle experience that you can bend a solid bar of equal diameter easier than you can a pipe. I discovered this using levers for various tasks and eventually got curious enough to read up on it a bit. It has something to do with surface area. Go figure. So my point is that it is very possible that tube will continue to do its job.

I think you should post that photo in a thread of its own and see what kind of responses you get. I am willing to bet somebody out there has broken a lower tube on their frame while riding. I would be curious to know how they discovered it. I am just guessing that the first thing you would notice is the vibration of the bike would change due to the isolastics being stressed in a new manner. Prolonged use would most likely start to stress things better not stressed, like primary transmissions, engine to cradle interfaces and such. However, I have a hard time seeing a total failure of the structure. There are photos around of frames that have had some extra braces and a few extra gussets added. I wonder if this wouldn't be a good avenue for you here. Spread out the stress and go ride. I would however, say you should get a more educated opinion than mine before deciding this.

On a slightly related topic. My '74 project was sitting so deep in the mud when I found it that I couldn't see if it had mufflers on it, which in fact had rotted off. I was more than a little concerned that the frame would be a wreck. As it turns out the paint was near perfect. The cradle looks brand new. So, what conditions exist for a frame to be that pitted? Not that this will help you sleep at night, but you gotta wonder if there were impurites in the steel to begin with.

Russ

Hi tocino
Check your frame for straightness using the Workshop manual under the Frame and Ancillaries section to make sure it did not have a bad crash. A look with a straight edge on the main tube and a 3 ft drill rod through the head bearings will tell you how things are. Note: Most main tubes have a slight bend to them. As I see it (looking at your bottom frame tubes in your picture) I would sand blast the area in question. Take it to a weld shop, which has a TIG welder and a welder who knows what he is doing, and have him fill the pits with wire. You can later use a file to radius the puddle welded areas to the same dimensions as the tube and then a final sand with sandpaper tape. I don't think this frame is a loss but you have to take it to the bare metal to make that decision.
my 2 cents
CNN

tocino said:

What really got me on this one, even though there's lots of corrosion and rust, was how un-bodged (to put it politely) everything was.

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Lucky you .... :wink: I just spend some "quality workshop time" drilling out the soldered lead "plugs" one of the FDPOs decided to put into the head oil feeds. I'm still undecided whether this or the rigid struts - 2" shorter than the shocks, must have been very interesting to ride in combination with the 3-4" longer Showa forks and Betors (without yoke end stops off course) - or the numerous holes he drilled in the frame to route the wiring etc. through is the worst bodge-job on that poor old motorcycle. Not that it couldn't be rectified but my forehead aches a bit from banging it against every solid object available.



Tim

Just got back from the welder - his recommendation is a new frame, or weld in new lower rails. He comes highly recommended and has worked on Commando frames before so I trust his opinion. Luckily I may have a line on a damaged frame with good lower rails. I'd rather go the "replace" route than a completely new frame. I'd like to keep the frame #.

Harbor freight sells number stamps, so frame numbers are no problem

Good choice salvaging lower rails off another frame. Easy welds and good as new. the lower rails aren't as stressed as any of the other members (between front iso mount and rear triangulated joint).

tocino said:

Just got back from the welder - his recommendation is a new frame, or weld in new lower rails. He comes highly recommended and has worked on Commando frames before so I trust his opinion. Luckily I may have a line on a damaged frame with good lower rails. I'd rather go the "replace" route than a completely new frame. I'd like to keep the frame #.

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Numbers aren't stamped on the frame.

tocino said:

I'd rather go the "replace" route than a completely new frame. I'd like to keep the frame #.

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Unless it is a very early Commando there is no frame no. in the sense of a VIN on them. I don't know how it is handled in your part of the world but replacing a FUBAR frame is legal here in Germany if the replacement is identical (read: sufficiently similar) to the original. The ANIL replacement frames come without the riveted-on plate so doing a replacement is straightforward.


Tim

swooshdave said:

Numbers aren't stamped on the frame.

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There is a frame production number stamped on the headstock. It is not a VIN (i.e. not identical to the engine number). In this (blurry) photo you can (barely) see it. I'd like to keep the fame number with the engine number.

Tocino, the number you are referencing is not the number that matches your motor gearbox. There should have been a number plate riveted to the front of the headstock with the frame number matching motor and gearbox.

Yes, the plate looks like this, they are available blank, I think about $10, and you can stamp them, I took it to a jeweler and had mine engraved. Your model should have a later style plate. Old Britts has them as well as a lot of others.



Dave
69S

Nice as a new birth certificate! I'm leaving Ms Peel in almost unreadable trashed state just for evidence of what she really is under neath, an old cast iron era push rod.

tocino said:

swooshdave said:

Numbers aren't stamped on the frame.

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There is a frame production number stamped on the headstock. It is not a VIN (i.e. not identical to the engine number). In this (blurry) photo you can (barely) see it. I'd like to keep the fame number with the engine number.

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That is not a sequential number. I think it's just a part number. Swapping frames with Commandos is extremely common, especially since they are so interchangeable.

According to http://atlanticgreen.com/commandoframes.htm my understanding is that this is a frame production number and not a part number, although maybe it's really the same thing. I *do* understand it's not the VIN and that the metal plate (which I have) carries the VIN so I could swap to any Commando frame. I just want to keep it as close to originally shipped as possible. Plus a new frame would probably be rather pricey!
My interwebs readings indicate that the 'F' in my frame # (*850* F11741) indicates an Italian made frame of metric dimensions, and that Norton had them stamped as a QA effort.

The sensible option suggested wins: it's a new frame. The guy I was going to buy a messed-up frame from for replacement rails has an good condition 850 frame for less than what it would ultimately cost to get mine repaired. Plus it's powdercoated.