73 Commando frame repairs

Previously christopher_winsby wrote:

Previously david_watkins wrote:

Hi all, new member in NZ.

I have a 1973 Commando 850 (was a Hi Rider) that I have striped to the bone in order to restore it. I had planned to include some new design bits but mostly to keep it standard with Andover parts.

Sadly the frame is bent. The top tube is bent down 1/4" from the middle to the stearing head. Both front down tubes are slightly bent in a kind of cork screw mannor 'cause there were crash bars fitted. The rear loop is bent down as is common to these bikes. The swing arm is also tweeked, right arm up about 1/4". Also the right side zed plate is bent inward at the bottom edge a bit. So, a we bit of a mess.

Can this frame be repaired or should I dump it and sell the rest of the bike off in parts ?

I owned Commandos back in the early '70's, both new and used. As I'm close to retirement I am reliving my very mis-spent youth and trying to get some fun out of those fond memories on Nortons. I've owned so many other bikes, couldn't list them, and have good mechanical skills. So far it isn't looking too good, the motor is a mess as is the gear box.

I can do most of the work needed to restore the bike as they are rather simple devices and I have loads of 'English spanners' and equipment.

At the moment it's a love hate thing happening.

All advice welcome.

Have a look at Andover Norton web site. A new Frame is £845 then you have tax and shipping. They also show and list Frame tubes and brackets etc. So you can work out costs of repairing or replacing. There are a few parts that are unavailable for the bikes but most can be obtained or replaced with improved parts . It all depends on what you are prepared to spend. To repair the old frame you really need an alignment jig and a good welder.

I would price all the parts needed and list all the work required and then decide what to do. Costs can escalate if you are not carefull

Thanx Chris,

Costs, indeed the idea is to keep cost down. I saw the Andover site but am woried I'll get into more of a mess by cutting and welding in new tubes as no one down here has a Norton jig. And I want to keep the factory matching numbers. Food for thought.

Previously john_holmes wrote:

The top tube is bent down 1/4" from the middle to the stearing head. Both front down tubes are slightly bent in a kind of cork screw mannor 'cause there were crash bars fitted. The rear loop is bent down as is common to these bikes. The swing arm is also tweeked, right arm up about 1/4".

This is repairable. You need someone with a Motoliner, they may need you to bolt the cases and isolastics back into the frame to hold the swingarm in position so they can check all the datums, Motoliner of Kent have a jig for this so they may be able to provide dimensions to NZ or you fit the cases and Iso's.

Thanx John,

I will seek out the info you mentioned. Need new ISO rubbers too but don't want to spend if it can't be mend. Shipping down to NZ costs deep in the purse.

Previously david_evans wrote:

all Commando top tubes are bent down because they bend during the welding process, the rear frame loop can be straightened with an oxy-acetelyne torch ( parallel to the bottom frame loop tube is good enough) Take the opportunity to gusset the rear frame loop alongside the inner upper top damper plates. The front down tubes just need to be straightened and particular attention paid to the sideways distortion, If the front iso bolt slips through without a struggle it won't be far out. That should keep you going for a bit

Thanx Dave,

Interesting re the top tubes bending due to welding process. The small tube under the top tube is bent up at the ISO mount.

I have read about gusseting the rear loop, good idea. In part, that bent cause the Hi-Rider sissy bar was on the bike, with the Roadster seat, so a leaver it must have been. And the previous owner has a very fat wife leaning back on it. Interestingly, there was a serious tire mark under the rear mudguard at the top so the bike has bottomed out the rear suspension at some time.

I looked at the front ISO and found that there is uneven wear on the end cup the shims sit in suggesting it was out o whack. But then the rubbers are totally shot.

All the fun in the world. But why the swing arm bent is a guess.

To add to my previous post. The front mudguard has a large dent right where it would line up with crash bar mount on the frame. So this bike must have had a head on with something at some time. The front wheel is a Dunlop rim and the rear a Jones, suggesting the front wheel is off another bike. The front rim has more rust than the rear and the spokes look more corroded adding to my suspicion that I bought a lemon. Such is life.

Previously john_holmes wrote:

I have put straight edges on both undamaged and front end accident damaged frame top tubes, All are bent but the accident damaged one more than the undamaged one, the damaged one showed 5/16" and the undamaged one 1/8" so 1/4" would signify a damaged frame IMHO.

Thanx John,

It looks more likely that I will be selling the bike off as parts; maybe. The gear box is totaly shot too, case is split between the bearings and all gears are eroded beyond help. Will cost too much to restore, with non matching numbers the value will fall. Motor nees a total rebuild too. Such fun !

Previously david_evans wrote:

I wouldn't expect the small tube under the spine to be bent, so you suspicion of a crash are probably well founded, The combination of a large pillion and a bent down rear loop is going to give the witness mark on the rear mudguard you describe. I wouldn't be surprised if there were two odd wheel rims as the factory probably just used what was in stock at the time, the rear would be less likely to corrode because it's normally well inhibited by chain grease. The front one that is in view, is popular for cleaning. The big issue for this frame would be any signs of damage where the large spine tube joins the headstock. That is a substantial joint, any damage there and I would be tempted to seek another frame. (There was a frame advertised in the classifieds)

Thanx David,

I couldn't detect cracking of the top tube to stearing head weld but it could be there. So, I will get it magnafluxed to make sure. The bend in the small top tube does it for me. As the forks were forced back into the frame the small tube took the brunt at the point where the head steady connects. I guess the energy forced the weakest point to give. If I do decide to restor this lemon I will prob buy a new frame. Don't want to buy and ship a frame all this way being unsure of its condition. Andover got any deals on frames ?

Previously john_holmes wrote:

Try

https://f1e.nz/Services/ChassisS.htm

Website is difficult to get to in Chrome as its security cert is invalid but go advanced and accept the risk.

Steve Bridges in Hamilton, and he has done Commando frames.

Thanx John,

I will contact him.

Kind regards,

Dave.

Previously martyn_watson wrote:

Hi David,

Whereabouts in NZ are you? I'm in Swanson in Auckland.

Regards

Marty

Hi Marty,

I'm down in Kapiti mate.

Cheers,

Dave

Previously martyn_watson wrote:

Hi Dave,

If you get stuck Ihave a mate up here with a frame jig that does frame repairs.

If you decide to abandon the project, let me know, I'll be interestedintaking it off your hands.

Regards

Marty

Hi Marty,

Just found this message.

After much cursing and agro I have decided to carry on rebuilding this bike. Now that I have sorted the frame it seems the waters are somewhat calmer. I've made a new contact locally who can help with restoring the gear box and other bits. There are so many amazingly tallented guys here who can do all sorts of wonders to keep old bike on the road.

I hope to have this bike on the road by spring.

Going to paint it Aubergine. My wife wants me to paint it hot pink.

By the way, I live a mile from the place where they make the gears for TTIndustries.

Chocks away,

Dave

Previously martyn_watson wrote:

Whilst it seems like a daunting task rebuilding the bike can actually be therapeutic, i try to think of it as a series of small victories, hopefully the victories outweigh the persistant problems....

The gearboxes are a piece of doddle to rebuild, invariably they all suffer with the same faults and the support is good and while not inexpensive, the bits are easy to get.

If you need any help, don't hesitate to post on here or pm me. I prefer to figure things out for myself rather than employ self professed experts.

Hi Martyn,

Nothing I like better than rebuilding a motorcycle to a good standard. Trouble is that I am almost OCD about it, so everything has to be spot on. I can't stand shabby work or burried 'treasure' under paint etc. I clean everything and make sure it all goes back together right. Otherwise why do it ?

My dear wife thinks I put too much into it but I usually think I haven't done enough. I polish alloy by hand to a mirror finish.

Thanx for the kind offer of help.

I sometimes do make parts to improve on things that I think the factory had to ecconomise on. All brands, not just Norton.

Chocks away,

Dave

Finally the bent Commando frame is square to the world. I took it to a friends brother who has a tool makers table. With a tweek here and there the sucker lined up. Cosmetic frame injuries have been cleaned up. Looks as good as it's going to get. Will paint it black with clear coat. A local mechanic wanted 850 bux to do the job. I love rubber hammers.