70 Roadster rebuild

I've owned my 70 Commando for three years, but seemed to have accumulated a lot of spares. Decided to make more room in the garage by using these to build another bike (if that makes sense).

Done some work on my 70 to upgrade it and keep it running over the last few years, but nothing major, so this will be a fairly standard rebuild.

Here's the pile including engine, trans (not shown), drum brake wheels and fenders, oil tank and carb (not shown). Frame, swing arm, side covers and a few other goodies from a member on here (thanks Cj).

Frame and swingarm. Wheels behind the lift


Engine


Timing gear looks good


Marzocchi forks will not be used:



Swing arm has been repaired at some point





Frame looks good



Any idea which year the frame might be?



Hint might be the bearing races that came out with the aid of some heat and a drift

The headstock tube looks to be in good condition



Rear ISOs not so good with lots of rust in the tube









Does the weld look ok? I cant see any cracks.



Swing arm gunk


Spindle coming out with the aid of the bolt from my clutch spring compressor




Spindle out. Quite pitted


Next step is to remove the swing arm bushes.

Questions:
Frame year?
Rust inside rear ISO tube - will this clean up ok?
Weld on engine cradle - what to look for in deciding the cradle can be reused?

Might be a '71 frame, but I'm not positive.

Rust inside the iso tube should clean up with some scraping then a small hone. Might result in too-loose fit unless you are able to try 2 or 3 variants of adjustable iso units. No guarantees.

I can't comment on the welds other than they look good from a few feet away.

Spindle has been errantly GREASED instead of lubed with heavy oil. New spindle recommended.

Looks like a decent project.

Nice trick for pulling the spindle. Will have to try that in a couple days after I get over the flu.

freefly103 said:

Frame year?

Click to expand...

1969-70 as it has the cross-member (with the centre stand mounting plates) beneath the gearbox.

Frame and swing arm are out for powder coating. Should be ready in two weeks.

In the mean time, time to get started on other stuff e.g. build front forks.

Delivery of some goodies today from AN and Minnovation (Falcon shocks).



Decided to go with a new tranny cradle. AN kind enough to provide their fork building instructions. Not sure where I would have started without these.

Building a bike from parts is a heck of an expensive way to do it.

(don't ask how I know this)

Tell me about it.

I have most of what I need. Not the forks obviously. Trying to find good used parts where I can. In the case of the forks, I couldn't find any decent second hand part except for the yokes which I bought on Fleabay for $100.

Now mostly need the missing fasteners, and

Inner primary and outer primary covers

Final drive chain and mudguard

Side stand

Petrol tank

Headlamp, tail lamp

Speedo and tacho.

Just another few bucks!

I have a decent speedo & tach that I'll sell cheap. Formerly green blob on one of them looks blue now, but they should be good to go.

Visited Malta Powdercoat today. Essentially a one man operation running out of a garage which is very common in this part of the world.

He had a few goodies waiting for me:





Looks like he's done a pretty good job. Frame has been blasted, primed and powder coated. I had to sort out a few frame issues before the frame was powder coated, however.

This included removing the head steady bolts from the main frame tube.

One snapped. Managed to retrieve the snapped end but now need to run a tap through there.

What is the thread of that head steady bolt?

freefly103 said:

What is the thread of that head steady bolt?

Click to expand...

Assuming you mean the holes for the AV mounts?

5/16 - 24 UNF.

Hi.
The cradle has the stock welding.
You can see on all this item if you sand bladt they.
Is a special league welded.
Ciao
Piero

freefly103 said:

Trying to find good used parts where I can. In the case of the forks, I couldn't find any decent second hand part except for the yokes which I bought on Fleabay for $100.

Now mostly need the missing fasteners, and

Inner primary and outer primary covers

Final drive chain and mudguard

Side stand

Petrol tank

Headlamp, tail lamp

Speedo and tacho.

Just another few bucks!

Click to expand...

I have some spares off my bike I just stripped down, in various states. Fork tubes with minor pitting, headlamp bucket with same,fasteners, etc.

Send me a pm if interested.

Decided to put the swing arm together today. New bushes and spindle went in with the help of a little heat and cold, the clutch spring compressor and front pulley puller.

Had some time so then put the swing arm and shocks in the frame.

Looks ok, with cafe seat supplied by a Vietnamese co selling cafe seats for Commandos (fit is with standard tangs per Norton seats):







Frame looks straight but now with the swing arm in, will take a few measurements.








Lessons from today:
Put the oil tank in first, then the battery tray before the swing arm and engine cradle.
Assume nothing fits without checking and adjusting, and some times modding.

Questions:
After copious reading on here, have decided to ditch the 850 yokes and buy matching 750 yokes for this 70 750 frame. Has any one have actual experience with 850 yokes in a 750 frame?
There is light rust inside the central oil tank. YouTuber's vids suggest soaking the inside with apple vinegar. Any one tried this? Other solutions?

Next:
Install yokes, steering head bearings, forks, tranny, engine (when its back from Steve Maney).

I wouldn't install shocks with the damper at the top, unless they are designed to work in that orientation.

Will check the install instructions, but the Falcons installed on my Seeley (by NYC Norton, i.e. with much more knowledge than me) came that way, so assumed that was the correct orientation:

Not all shocks are alike.

The inverted but standard-looking rear shocks for the '79 Triumph 750 Bonneville T140D Special will fail if installed with the dampers on the bottom!

freefly103 said:

............ Frame, swing arm, side covers and a few other goodies from a member on here (thanks Cj).

Frame and swingarm. Wheels behind the lift

Questions:
Frame year?
Rust inside rear ISO tube - will this clean up ok?
Weld on engine cradle - what to look for in deciding the cradle can be reused?

Click to expand...

Glad everything arrived okay Joe. I was told that it was a '69 frame and I believe that those are the original welds /Brazed joints on the cradle. You are making great progress! Really nice sealy you've got there :mrgreen:

Some more progress:

Forks and yokes assembled. Fork stanchions not fully seated yet in top yokes. Still waiting on instrument cups before I do that:



Went with a sealed bearing at the top and a taper bearing at the bottom. After a lot of reading on here, seems that there is no clear and correct choice of bearings to replace the cup and ball races that are original on this frame. Also chose to use 70 yokes to match the 70 frame (I sold the 850 Ang yokes on F_Bay - thanks to who ever bought those):



Lower end back from Mr Maney for a freshen up and to install a CNW breather. Second transmission lollipop adjuster installed, as this bike will have a belt drive fitted:






Transmission also in:




When I removed the timing cover and oil pump to send it to AMR for their mod, the oil pump gasket has been installed upside down, partially covering one of the feed/return holes. Upon checking the bearings that were replaced, it didnt seem to have been a problem. Good to have it sorted though.



The bearings don't look original to me, so it seems that the bottom end must have had some attention at some time in the past, and this may have been when the oil pump gasket was inverted. Theyare in good condition:

Starting to look like a Commando again:



Cylinder head attached, not without some fiddling with locating the push rods. Dave Taylor head steady installed. Single Mikuni attached. CNW head light ears on (forgot to put them on as I was installing the stanchions and yokes, so a bit of unnecessary re-work).

Wheels back on. Am going with a GPS speedo so KC of NYC Norton is making a spacer to replace the self expanding speedo drive which is no longer required.

Ordered a Norvil tank and a few other bits a pieces today, so that should be about it for the major parts, but I can see there is still a lot of small fiddly stuff to do, not the least of which is a new chain on the 19 tooth sprocket, Tri-spark, wiring harness etc.

The crappy centre stand has to go, decided to install the newer version that swings off the tranny cradle since the cradle I bought has those holes drilled in it already.

Still waiting for the timing cover, trans cover and outer primary to come back from polishing.

Is that Vietnam Cafe seat for the Interstate tank?
I've been eyeing the Interstate version on eBay to go with my India Interstate tank and was wondering how it looked mounted with the tank.