Topic: Sandcast #97 restoration

[markb]

I guess I agree with that. If I had enough of the rubber inserts to install in the original cylinder I probably would go that way. Before I do anything I am going to try to find some, again. Past experience was they are pretty rare, at least to get the right color.

[MauiK3]

If you can't find the right rubber bumpers (vibration attenuators?) you could document the change and put a newer set in so it's mechanically correct and sound, that would seem to satisfy the need for the bumpers and the need for historical correctness.
Number 97 now has a life of its own and should be somewhere where it will be preserved. Ridden as well but preserved.
If I were ever to rescue another it would be a K0 and maybe a sandcast if possible. As a design they were not perfect but as we all know, that's not the point, they were the first and as such they are awesome. As time goes by they will get harder and harder to bring back properly.
I'm getting excessively reverent here :-))
I'm not a habitual restorer like so many here but I really respect the process, I've just got too may things going on to do it very much. As a habitual DIY I seem to always get into stuff, like I'm about to start my kitchen over (again).
#97 is wonderful and I'd buy it if I could afford it. Keep up the stellar work.

[markb]

So I decided to go with the original jugs. I figured I would keep looking until I found the inserts. Here I am ready to put it back together.

Things are going pretty good and I took a little break and checked the SOOC website and one of the guys had a link for an eBay sale that had the inserts. Sweet. Now I feel good about my decision. So I got the jugs and head on and I’m thinking could things go any better. Well the answer to that was no. I torqued down the 16 head nuts and then when torqueing the 6mm screws under the pucks, one of them stripped out.   

That’s where I quit for the day yesterday so I could think about what to do. I decided to heli-coil it. I thought about trying to do it in place but decided the best is to pull the cylinder off and do it right. There isn’t a lot of room between the hole and the flange on the cylinder sleeve so it seems like the tap drill and tap may go into the flange. I think the sleeve is soft enough for that. My only other decision now is while I’m at it should I do all four?

[kmb69]

.....
My only other decision now is while I’m at it should I do all four?

Yes, heli-coil all 4.

Not sure what you were using but, you need to be real careful torqueing 6mm screws. I prefer to use a 1/4" beam type torque wrench for small screws versus a "clicker". Most "clickers" say specifically their quoted accuracy is "when they left the factory" if you get my drift.

[markb]

Seems like the thing to do doesn’t it. I do have the clicker type but I check it quite often. For 6mm bolts I try to stay around 80 lbs. in.

[MCRider]

Its always been my opinion that the 4 6mm bolts UNDER THE PUCKS, are there for convenience. To draw the head down in a uniform way before getting on the head nuts. The head nuts do the heavy lifting. 4 6mm bolts in soft aluminum can't be expected to do anything else of any value. In fact its my opinion that after torquing the nuts those bolts are immaterial and should only be tight enough to keep them from backing out and rattle around. Heck I think you could leave them out entirely, truth be told.

But its not my bike.   

[markb]

Heck I think you could leave them out entirely, truth be told.

I've thought about that too.  It does seem like they don't do much. However, I am going to put them in.

I been told that when tightening you need to do the nuts first then the screws otherwise the screws will be loose. When loosening do the screws first then the nuts otherwise the screws will get tighter. Seems logical to me.

[MCRider]

Righto.

AS to order, I tighten the 6mm down first to gently pull the head down against the friction of the dowels, stop at hand tight. Then yes, they will be loose again after the nuts, and will need to be hand tightened again.

The comment about order of removing, is VERY important. 6mm bolts first, then the nuts. Otherwise the 6mm will become so tight as to be often mangled or even broken off when removing.

One time I removed the nuts first and had to put them back on to get the 6mm out.

[markb]

I pulled the head and cylinders off and installed Heli-coils. I thought about doing the one in place but decided against it because of the accuracy and the chips. I looked at all of the 6mm holes and at least one more of them looked suspect so I did all four under the pucks.


They were pretty close to the sleeve flanges but the tap just barely went into the flange.


While I was at it I did the rear one too. I don't want to pull it apart again.

[MauiK3]

That looks like it should hold up fine. Those fasteners likely help the gasket to stay in place and not creep over time from heat movement.

[markb]

Finally, the cylinder and head assembled. The original cylinder and head. The 6mm screws torqued down just fine. I’m happy I went that route in spite of the extra work.


Here’s a shot where you can see the two small o-rings under the towers instead of four on later heads. I did that to document that the original head was in fact installed. 

[MauiK3]

Steve-O said I should do another bike.
I resist because of the other projects I have going, not bike related.
Seeing your #97, however, makes this hard to resist. I look through craigslist and cycletrader and see various CB750's, some very expensive and already done and some horribly molested at high prices. I guess if I ever saw one that looked right I'd have to consider it.
Yikes, this thread is dangerous!!
Keep up the good work, it's great fun reading it.

[markb]

Well, things were going good. I got the camshaft holders and cam installed and when I torqued the 56mm screws for the caps three out of four of them stripped out.    It’s the holes with the pins (circled in red).


So the head is back off. Three steps forward, two steps back. These are going to be a little bit trickier because of the counter bore for the pin. Fortunately the O.D. of the Heli-coil is smaller than the 8mm pin hole. Not much choice as to what kind of insert to use here.

Some of you may be thinking that I’m maybe just over torqueing the screws. They weren’t even close when they let go. To make sure I checked my torque wrench again and it is right on. This is the first time assembling this cylinder and head since they came apart. And you probably recall that they came apart hard. I’m guessing the threads were damaged then. The other thing is that the 56mm screws could be a little longer. In fact on later K0s the screw is a 60mm. If you subtract the washer and the thickness of the holder and cap and the 8mm depth of the pin hole and actual length of the screw you’re lucky to have 8mm of thread engagement. With a 60mm screw in would be 12mm engagement which would be a significant improvement.

I’m also going to be checking all of the tapped holes for the valve cover before I put the head back on.

[markb]

I’m almost ready to put the engine back in the frame. 


I Heli-coiled the holes with the pins under the cam holders. As long as I had to do it I did all four. Then I assembled the cam towers before mounting the head to make sure everything else would torque down. I also checked the valve cover. I’m glad I did. I had three of the 63mm pan head screws that were about 0.5mm from tightening, even with the gasket. Almost didn’t notice it. I thought they were tight but they were bottoming out in the tapped holes. I thought about just regrinding the screws down for those holes but if and when it comes apart again it might not be noticed. Just the kind of stuff that previous owners do to mess us up. I was able to run a tap in those holes and get just enough thread. I checked the cam chain tensioner too. I stripped out a hole for that years ago (and I Heli-coiled it). The early parts book calls out a 36mm screw and later it was changed to 40mm. I checked and there wasn’t much of the screw sticking out with the 36mm. The tapped holes were just deep enough to use the 40mm screws. So I decided it was better to be safe than correct.

I got my rubber inserts for the fins. Just started putting them in when I ran out of gas. They go in pretty tight. The last thing I want to chance is cracking a fin. I think I’m going to trying heating them or boiling them in water to soften them up a bit.

[Tews19]

Wow, you are moving fast now that you are back at it! Shoot, How much do you charge to assemble a K0 engine!??

[markb]

Basically putting top end together three times in a week does make it go a little faster. To answer your question, it depends on how much rework.    I couldn't have afforded this job if I had to pay someone to do it.

[MauiK3]

Looking great, this one is worth the work.

[MauiK3]

How is #97?

[markb]

Really good. As of yesterday she is finally together again. Once I got the engine together things went pretty good. So now in addition to the original cases it has the original cylinders and head along with the original valve cover.

I also found that the front brake was sticking so I had to pull the caliper apart and while I was at it I cleaned up the master cylinder and flushed the rest of the system. It had sat for quite a while. Works good now.


Here’s some pics of my setup for installing the engine.


Of course it helps to have a nice hoist.


Start to finish about 45 minutes and no nicks.


And I forgot to mention I now have the correct spoke nipples installed. I have a few more details to correct but she’s getting close to being as correct as humanly possible.

[MauiK3]

Beautiful
So it is now like a Vic World sandcast, maybe better. What a great example. It needs to be preserved somewhere.

If I may pry, what is the shop you are in used for? It's so clean!!!!

[MoMo]

Beautiful
So it is now like a Vic World sandcast, maybe better. What a great example. It needs to be preserved somewhere.

If I may pry, what is the shop you are in used for? It's so clean!!!!

and quite large to boot,  envious

[fastbroshi]

And I forgot to mention I now have the correct spoke nipples installed. I have a few more details to correct but she’s getting close to being as correct as humanly possible.

What's so special about these spoke nipples?

[markb]

Beautiful
So it is now like a Vic World sandcast, maybe better. What a great example. It needs to be preserved somewhere.

If I may pry, what is the shop you are in used for? It's so clean!!!!

Thanks for the compliments.

It's my company's shop. I have a little area where I work on my bikes. It's a bonus to have all the other resources available.

[markb]

What's so special about these spoke nipples?

The correct nipple is on the right. See how it’s turned down on the end.

[markb]

I took some time this weekend to go the Minneapolis Motorcycle Show.


The local chapter of the Antique Motorcycle Club of America asked me to bring 97 to display.


That’s why I needed to get it back together.


I answered a lot of questions. It’s amazing how many people have at least heard of a sandcast.