1961 CB72 Project

[sarals]

Nice to see you back to your project. I've missed your informative posts.

So have I!!!

[G-Man]

Sara

This year is going to be a tricky one, work-wise. I will try to make progress but it could be slow.

You need another project. 😊

G

Nice to see you back to your project. I've missed your informative posts.

So have I!!!

[G-Man]

After a couple of weeks of travelling I was really looking forward to some time in the workshop. I have been carefully planning how I would go about my first kickstarter cover transplant and decided to bolt each cover in turn to a wooden fixture so that I could mark out the same cut line on the donor and recipent covers.....



I drilled some holes and bolted each cover on and used the same center-mark to sweep my dividers in an arc.

The second cover got the same arc drawn...



Once I had them marked out it was pretty easy to pop them in my small bandsaw and cut along the lines. One part was cut slightly inside the line and the other slightly outside so that I would have an even gap into which to run the aluminium solder.

Here are the parts awaiting cleaning up.



I followed the instructions in the Techno-Weld site and cleaned everything up with wet-or dry paper and stainless wire brush.

http://www.techno-weld.co.uk/home.html

As per the instructions the first job is to heat up and 'tin' each piece. I lagged the bigger piece to stop heat loss but the smaller part could be heated up with ease. You warm the part wth the gas torch and keep testing the rod on the part. When the rod melts on contact with the surface you are good to go. Run a small pool on to the part and then scrape through the puddle with the stainless steel abrader to break up the oxide layer. Once you have practised (I have used this a lot over the years) it is quite easy to maintain the temperature and swap between torch, rod, and abrader. You really need three hands so there is no photographic evidence, I'm afraid.

Here are the donor and recipient covers after the welding and subsequent fettling processes. I used my small mini grinder / sander to clean up the join and because the two castings were not identical in profile (early / late types) I had to use extra filler rod to join the two profiles smoothly.



Overall I'm quite pleased with the way the parts went together and now have them strongly joined.

Here is a close up of the outside after initial grinding.



And here is the inside...



You can still see the semi-circular joint but that won't really show up when it has been sanded and painted.

It's nice to think that I have recovered this rare early cover to go on my project. I have another one to do but that should be simpler. :-)

G

[G-Man]

After this morning's success I though I might as well do the second cover while I was in the 'sweet spot'. This one needed a different technique as the generator 'rim' had two chunks broken out of it. It seemed like the best option woukld be to cut out two slots in the miller, then cut mating pieces from the donor part and let them in after tinning both halves.



This worked pretty well, but the castings were, again, slightly different sections so it was impossible to make a perfect repair without using some filler rod to take up the slack. Even so I was quite pleased with the alignment I got.



With a bit of fettling with my grinder / sander. It was looking pretty decent inside and out.



Here it it aslongside the donor again. Still plenty of useful stuff on my 'donor' so It will be put somewhere safe....



And there we are. Normally my first day in the workshop after a trip is spent just trying to remember where I got to and just cleaning things. I hit the ground running today and happy that things fell into place.



Three broken covers turned into two good ones and a donor with plenty of life feels like 'a good day at the office'.


G

[LOUD MOUSE]

Looking good G. ................lm

After this morning's success I though I might as well do the second cover while I was in the 'sweet spot'. This one needed a different technique as the generator 'rim' had two chunks broken out of it. It seemsed like the best option woukld be to cut out two slots in the miller, then cut mating pieces from the donor part and let them in after tinning both halves.

[G-Man]

Thanks LM!

I have two burned fingers and managed to catch two more on the sander. Apart from that, a good day..... :-)

G

Looking good G. ................lm

After this morning's success I though I might as well do the second cover while I was in the 'sweet spot'. This one needed a different technique as the generator 'rim' had two chunks broken out of it. It seemsed like the best option woukld be to cut out two slots in the miller, then cut mating pieces from the donor part and let them in after tinning both halves.

[OldScrambler]

Great Save!................Now I am inspired to do something with my broken covers..........The possible solution to get the rod-metal to match the cover is to make rods from a throw-away cover. That technique worked on a friends restoration of an early rotor-cover for a sand-cast CB750.