SANDCAST VS DIECAST ALUMINUM INSTRUMENT BODIES

[1941wld]

I see a lot of tach and speedos on eBay for sale. Please tell me the difference between the aluminum instrument bodies. When did the diecast instrument first appear on the scene?

This must be a CB750 versus CB750 K0 stuff.

I want all who read this forum to understand this difference and be more knowledgeable. eBay vendors think all are the same and I don't think they are.

Thanks for spreading the information.

[1941wld]

I'm talking about the aluminum drive body screwed to the bottom of the instrument.

[1941wld]

I asked Vic W. and he confirmed there was a change in the cable drive gear housing from sandcast to die cast in late 1969. So when I'm looking at gauge for sale I can now tell if it is correct for my application.

Anyone out there has a picture of a die cast cable drive gear housing to compare?

Thanks, Conrad

[1941wld]

Just got an email for the man selling the speedo and tach on eBay. item #280536608894. He as confirmed that his are die cast. So these never came on a sandcast. Mystery solved! It's hard to keep up with all this information. Thanks to all you guys on this forum for recording this information.

[kp]

My diecast VIN 11970 came with sandcast drives so they were on all bikes up to at least that VIN. Vic is probably correct in that anything made in 1969 most probably had sandcast drives KP

[CB750faces.com (Lecram)]

After reading this topic, I investigated my 9 K0 gauges and discovered that two of them have the sand cast drive/cable connection, one miles speedo and one tacho.

How rare are these?

This is a sandcast next to a diecast:





The tacho and speedo:

[Steve Swan]

Thanks for posting these additional pics.  

A few years back, i put pictures in "Production Models" in the website with these 2 different sandcast drive bodies.

as well, i   think there might be a thread on this topic elsewhere in this BB.......

As i understand it, the earlier type has a machined right angle and the later type drive has the champfered edge.

The champfered edge type drive body was used beginning somewhat early vin "K0's."

[CB750faces.com (Lecram)]

I received a message from another member (I don't know if he wants to mention his name) and he said this, very useful info:
I suppose you are informed that the first sandcast had a sandcasted gear without bevel. Later (about #2000 and up to K0 around #12000) had a second kind of sandcasted gear with bevel. Later K0 had a diecasted gear and this gear was also used on K1 with another kind of housing/cover.

I also found a picture of the first one, until 2000:



This one is supplied from 2000 until 12000:



And this one from 12000 and later:

[vnz00]

Hi all, happy new years!

Regarding the sandcast drive change from square shoulder to bevel edged shoulder, my #1853 has the later bevel edged shoulder. So they would have started being used pre-2000 VIN.

I know Mark B bought #1553 recently which gave us a 300VIN range for the 2 hole recessed and non-recessed airbox. Mark, if you see this can you pls confirm you speedo drive too?

Regards, steven.

[markb]

Steve,
Here's some pics of the gauges that were on 1553.  I'm still learning about the differences here so I'm not sure what I've got yet.  Hopefully you experts can enlighten me.  They're not faded too badly but the speedo shows over 27,000 miles.  The chrome on the bottom covers was badly pitted so maybe these are originals.  Here's the speedo:








And the tach.

[vnz00]

Hi Mark,
Thanks for posting pics. The area we are looking at is just below the machined thread on the sandcast drive housing. Notice the bevel edge directly below? On early models this bevel didn't exist. It was a square shoulder.  Steve Swans post in another thread shows comparison pics quite clearly.

I see #1420 on eBay at the moment. I wonder what those drives are...

Regards, Steven.

[CB750faces.com (Lecram)]

I received some pictures from Bo-Göran who is also restoring K0 gauges and he sent me this picture, that shows exactly the differences between the first and second sandcast series. The gauge of Mark's bike is clearly a of the second series.
The inner gear of the second sandcast and third diecast seems more equal and exchangeable. The wheels of the 2nd sandcast ODO are of aluminium and of the diecast plastic.

[Steve Swan]

Hmmm............

I'm probably missing something blatantly obvious in the above picture, but I don't remember ever seeing a gauge frame as shown on the LH side on any sandcast (or "K0.")  I've had quite a few of these gauges and drives apart..........  

The RH frame is the type of frame i am accustomed to seeing on sandcasts (and "K0's.")

The LH gauge's frame appears stamped steel.........    

IF frame is stamped steel (not cast) aluminum, then the frame and gauge is  later  than K1.

I do reserve the right to be wrong, but i don't think i am.........  (but, would not be the first time )  

Unless, there is just something obvious i am simply overlooking or i do not understand what is written, the frame on the LH side looks like frames i have seen on K2-onward gauges......  

[Riccardo]

I agree with Steeve.

Never seen the left gear with conic screws.

The same for the counter frame, w/o alloy plate to install on the cup frame.

I can wrong, but.............?!!!!!

[kp]

I agree with Steve. Whilst anything is possible I prefer to go with what we already know unless we can identify what bike these instruments shown in the last picture can be identified. The instruments off Mark's 1553 are clearly bevel type sandcast and add a little more to pinning down type to which VIN.
I've added some pictures to add clarity for the information of members
Hope this helps fellas KP