Restoration of Sandcast #97

[markb]

Didn’t get anything done over the Thanksgiving weekend except pick up another bike.  I got an early VIN (15xx) that has the shortneck petcock and 2-hole airbox that I’ve been looking for.  The brake lines are better than the ones I have but I don’t know if they’re good enough yet.  So my list is getting shorter but I’m still missing one big item, the smooth oil filter cover.  Anyone have too many laying around and would like to sell one?     And I might use engine parts like the cylinders if I end up needing that.  I still haven’t decided what to do.  Also I haven’t decided what to do with the new bike.  There are a few smaller bits I’m going to use for now and maybe this will end up being my next project and I’ll have to start looking all over again.  Probably won’t be able to make it as correct as I’m trying to make 97 but for sure I’m going to keep the cases and the frame together.

[ashimotok0]

PLease, Please, Please, don't let me ever get a Sandcast!! It's been a nightmare sourcing bits for my K0 and I think something like a 'Sandcast' would 'tip me overthe edge' with obsession. It seems that once you guys get one Sandcast you then become serial SC collectors  

On the airbox, why don't you all  get together as a group  and approach LPM in the UK for him to reproduce you a few Sandcast airboxes from his prototype style tooling. I approached him a couple of years ago to produce small quanties of  'can crusher' body mouldings, which   I designed for one of my customers  and he was really receptive. He told me he spent his life designing and producing automotive mouldings, when he worked for Rover cars. From memory the owner is John and his son is Martyn. They were fairly large mouldings and he was busy at the time so I went with a rapid prototyped sample from 'The Product Workshop' in Rotherham UK (not too far from ChrisR) They made me silicone tooling from the original RP Chinese sample I had, which yields betwen 10 and 20 products. The latter process produces a surface finish which will even reproduce a fingerprint from the original moulding but the product is 'cast' and hence rather brittle. LPM use a form of hard polyurethane I believe.

Of course, if the part has to be original and in the fragile Styrene type plastic, then non of the above is of any use to you. Just a thought!!

Cheers

Ash

[markb]

Ash,
Yes my wife thinks I have a disease.  Fortunately she's a pretty good sport about it.
I like your idea on the airbox.  I've been satisfied with their 3-hole airbox.  I might try to contact them.  If someone beats me to it though I wouldn't have a problem with that.
Mark

[kp]

Fellas,
I contacted him last year and he can make a 2 hole version of his current air-box so there is no problem there it would seem. I didn't ask him about rigid plastic but I agree it would be great if he could produce one in a similar material and look. The biggest problem we have is that there are 3 versions of the K0 airbox. Early, middle and late. Bottoms are all the same but the tops differ significantly
KP

[markb]

I've started a separate thread about the 2-hole airbox to see if there's any interest to get together and get some made.  Here's the link:
http://cb750sandcastonly.com/smf_forum/index.php?topic=386.0
Mark

[markb]

I just had a huge surprise.  I knew the bike I picked up had a 2-hole airbox.  I never even looked to see if it had the reliefs because I assumed it wouldn't because it's a later number (1553).  I took it off tonight and it doesn't have reliefs!!  Even better it's in incredible condition.  I was kind of bummed out when I got home from picking it up all the way from New Jersey to Minnesota, because our house had been broken into.  This doesn't make up for that but it helps. 
One thing I need input on.  The center part is stuck to the top.  I didn't try very hard to separate them.  Does anyone have any suggestions for getting them apart without damaging them?
I don't have my camera with me but I will post pics as soon as I do.

[Steve Swan]

How about trying some AeroKroil....... ?  Or, WD40 ?   Both these penetrants should be benign and not cause damage.   Not sure what other fluid or solution i would feel comfortable using, without fearing damage...........  Hopefully the paint is just sticking the parts together and the center is not "glued" to the top from gasoline vapors.  Goes w/o saying, the plastic material the body parts are made from is BRITTLE.

[kp]

Caustic soda will dissolve the paint and not affect the plastic. Try a mild solution first. This usually unsticks the stick. If you are afraid to do that try straight white spirit vinegar, or straight hot water 

[markb]

Here’s pics of the 2-hole, no relief airbox.  I don’t think I’ve ever seen one in this good shape.  Too bad it’s the wrong color.  Minor detail.  By the way it’s much greener than the pics show.


Closeup of the corner with no relief.


I haven’t tried separating the middle from the top yet.


There are a couple of small cracks here but very repairable.


Bottom half.


Doesn’t show up in the pic well but the bottom is slightly warped.

[Wayne]

WOW! It looks to be in awesome shape Mark. Again, nice find!

[hondasan]

I'm guessing those two marks on the upper were caused by the frame tubes? That's why they relieved them, even if only to make it easier to fit them new in the factory without damaging the paint.

Chris R.

[markb]

Chris,
You are correct, that's exactly where the frame tubes are.
Mark

[Riccardo]

Mark,
also i've an air box without relief.
After repainted i've protected it with 3M clear film to prevent it by damages from frame.
Mark, dont try to remove the separator, it was cemented with the upper part from factory.
Infact you cannot find it in the part list as spare part available.
In the part list you can find the upper and the lower part only.
Dont try to extract,  there are many possibility of cracks.
I've repainted it with the upper part, togheter.

[markb]

Hi Riccardo,
You're right, the separator is not listed until K1 models.  None of the hardware inside the upper half is shown either supporting your observation.  I looked at it again and it is loose on one side.  I think I might try soaking it warm water just to see if the glue separates but if not I think I will follow your advice.  Thanks for the heads up.
Mark

[markb]

I hesitated posting this because I figure I might get some “I told you so’s”.  But maybe someone will have some good input so here goes and I know I’m not the first one this has happened to.  I had some time over the weekend so I decided to work on getting the starter motor out and tackle the studs.  I took it slow and worked on the motor for about an hour and finally got it out.  On to the studs.  I already had one out and had been heating and soaking all week.  A couple were a little stubborn so I heated and soaked them and moved on to the next ones.  After about another five hours, everything was going good until I got to #14.  I use a vice grip and if it slips I know the stud is still too tight.  This worked on my last two projects and never had a problem.  This one actually moved about a half a turn and SNAP.  Son of a….


Here’s a close-up.  It broke off about an 1/8” above flush.  That’s the good news.  I’m still thinking about what to do but I think I will make a bushing that’s c’bored on the bottom the diameter of the stud and a smaller hole drilled through the top so I can get a pilot hole exactly on center.  Then drill out the stud using an 8mm x 1.25 tap drill and then pick out the threads.  I’m thinking I might not keep track of my hours anymore.