Honda CB750 Sandcast

1969 Diecast/ K0 restoration

UK Pete · 135 · 78497

UK Pete

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I have gathered all my engine component markings, and have read other peoples posts on date markings,  what i can gather is 44 is the year 1969 and the next two numbers the  month and day, as i am documenting the whole build i might as well gather all my date markings together, it really pleases me that the bottom of this engine was totally untoched, the top had only had the head off, everything that was put together in 1969 is in tact and re-usable, obviously i will replace all the usuall serviceable items


Clutch basket 01/10/1969


cam carriers the  07/10/1969  first 4 is partly worn away




Rocker cover  29/8/1969


Crank cases  26/09/1969


UK Pete

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Gathered the bottom end parts together, took them apart and gave them a good clean and inspection, i have to say the condition for 43 years is amazing, very little wear, the only parts that need replacing are the primary chain tensioner and cam tensioner wheels as these are rock hard and starting to loose bits off them,and of course the chains will be replaced, i will change the output shaft outer bearing even though mine is smooth running and reusable, i am only changing it as i had already ordered the new bearing before checking the old




Output shaft has had an easy life by the looks


Started putting the parts together and back in the engine, it took me about 5 minutes to remember the easy way of reinstating the kickstart spring, i was scratching my head for ages trying to remember how the f--k  i did it last time, i put in the new primary chain tensioner,



Then the rest of the parts



It will stay like this for a while, till i get the rest of parts for the engine build, nearly there though, i have recieved most of the parts i ordered here they are , just need gaskets and a few more orings





Bowswell

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Hi Pete,on picture of primary chain,chains should not be exactly side by side, but one should be advanced one tooth. Often one is slightly longer than the other then the longest side will embrayage.Sorry for my English
cb750 k4-06/74
cb750k4 01/74
cb350f 1973
cb400T 1978
vulcan meanstreak


UK Pete

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Hi Bowswell, not quite sure what you mean, as far as i can see if the cogs are side by side then the chains will be side by side, thats exactly how they were when i took it apart, however i noticed a green and brown dot on the chains but i can find no mention anywhere as to what they are for

If anyone has any info on this subject please chime in as i dont want to mess up
Pete


Bowswell

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please check this and compare with yours picture.
cb750 k4-06/74
cb750k4 01/74
cb350f 1973
cb400T 1978
vulcan meanstreak


UK Pete

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What i see in your picture is the link plates are offset rather than side by side , is that what you meant, if so where did you find out this info, i have read everywhere i can, and googled the subject but not seen anything, i will see if i can find a Honda manual to download and check there next
Thanks for the information
Pete


Bowswell

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Yes,I can't find tread in soch4 forum or in HONDAMAN book.Something about harmonic noise or vibration in hi rpm.
cb750 k4-06/74
cb750k4 01/74
cb350f 1973
cb400T 1978
vulcan meanstreak


UK Pete

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Wish me luck as i am starting my gauge restoration, it is amazing just how much money there is in getting hold of a decent set of restored gauges, even the cost of home restoration on old gauges is high, with the potential to f--k it up as well
Anyway here goes

First of all snap of the rear plastic lip



Next carefully prise off the needle, this is the part where i wonder if i should be doing this myself


I got myself a small philips screwdriver which fitted the two face plate bolts and removed them, to reveal  beautifully preserved internals, even the light shaft rubber boots were intact and looking good,


The damping all seems fine, so i dont think there is much else to do in here, so i stick the the new jewels to the new face plate


Dab of paint on the needle tip, put it all to one side , let the paint dry and i come back to it for reassmbly later
« Last Edit: December 18, 2012, 03:22:50 am by UK Pete »


mcrider

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Yes,I can't find tread in soch4 forum or in HONDAMAN book.Something about harmonic noise or vibration in hi rpm.
This has been discussed many times at SOHC.net and is a pet of mine. I have reviewed many pictures of virgin lower ends and there is NO consistency from the factory as to whether the chains should be synched or staggered. Many people have stated that they should be one way or another, but there is no verifiable back up to either position. I am open to anything scientific one has to say.

I received this as a PM from HondaMan: "I'll make a post of this when I can get my picture, later, but...I just disassembled a virgin 750K7 engine and found painted-on timing 'marks' on the primary chains, and they align the plate-to-plate setup we were kicking around earlier. So, it looks like Honda aligned them instead of staggering them, when new." With his permission. "We were kicking around earlier" refers to the conversation he and I had on the subject.

 This is not conclusive as I have seen at least 2 virgin bottom ends where the chains were staggered. This leads me to believe Honda didn't care.  The chains in my current project are synched. FWIW.
Ron


UK Pete

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Quote from: bowswell link=topic=832.msg5821#msg5821 date=13548[color=red
[/color]20878]
Yes,I can't find tread in soch4 forum or in HONDAMAN book.Something about harmonic noise or vibration in hi rpm.
This has been discussed many times at SOHC.net and is a pet of mine. I have reviewed many pictures of virgin lower ends and there is NO consistency from the factory as to whether the chains should be synched or staggered. Many people have stated that they should be one way or another, but there is no verifiable back up to either position. I am open to anything scientific one has to say.

I received this as a PM from HondaMan: "I'll make a post of this when I can get my picture, later, but...I just disassembled a virgin 750K7 engine and found painted-on timing 'marks' on the primary chains, and they align the plate-to-plate setup we were kicking around earlier. So, it looks like Honda aligned them instead of staggering them, when new." With his permission. "We were kicking around earlier" refers to the conversation he and I had on the subject.[/color]

 This is not conclusive as I have seen at l[/color][/color]east 2 virgin bottom ends where the chains were staggered. This leads me to believe Honda didn't care.  The chains in my current project are synched. FWIW.
Ron

Good imformation Ron, for what its worth i have lined up the green dots on the chain, this makes it link to link


Ok so here are pictures of the gauges back together, there is still more work to be done, i will put new shrink tubing on the wiring, as it is getting a bit hard , also i wont seal up the bottom with silicon until the clocks are up and running on the bike, other than that here they are for know, all the hard work done











The rear chrome plates are ok but not perfect, thing is that the replacement ones from Honda are not the same as the originals, so its either keep as is , rechrome or replace with modern alternative


Here are the originals



here is an original left, next to the new style  right



UK Pete

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I was about to reassemble the bottom end the other day when i realised that the engine bolts were looking a bit scruffy , having gone to the trouble of restoring all other bits on the bike it would be a shame to leave out the engine bolts, so i spent a whole day yesterday blasting each bolt, then cleaning the threads followed by zinc/ nickle plating, i finished at about 9 in the evening,  i even did all the washers

Here are some pictures, i think a combination of passivating too long and the temperature gave mixed results, they have a sort of yellow hue to them which is exagerated by the flourescent lights, but on the whole i am very pleased i did it now, another job out the way
Upper and lower case bolts and washers seperated






kenhan

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Excellent! I am waiting for LeCrams gauge covers and I will doing this work soon.
When I was restoring my K2 gauges I used a fork to take off the needle. I worked perfect! Let the fork press on one of the (or both) small screws and it will be quite easy to get it loose.
I attach a picture!
/Ken
1969 CB750 Sandcast #5084 - running
1969 CB750 Sandcast #5128 - Running
1970 CB750 next project
1975 K2 (K3-5 donīt exist in Sweden) - Running
1981 Goldwing 1100 Interstate


Steve Swan

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The shaft the needle fits on to has a taper; as is the hole in needle which fits on shaft.

My experience, having restored around 20 sets of these gauges, give the needle a gentle anti-clockwise upward twisting motion, the needle comes right off. 

To re-install, give needle a gentle downward anti-clockwise motion.


nmbr12

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Greetings Mr Kenhan/Ken!I noticed you have no high beam/indicator lights on your spedo gauge-is your tac/rpm gauge also missing oil+neutral  idiot lights as my ko are?  Merry Christmas!  Tim


kenhan

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Hi nmbr12,
No itīs no problem, the example picture was from restoring my gauges for my K2 CB750. For my Sandcast I have the old gauges with plastic covers, beam and flasher lights and so on.

Merry Christmas to all of you!! In Sweden our Christmas day is dec 24 so at present it looks like a Disneymovie outside, lots of snow and new snow pouring slowly down!

/Ken
1969 CB750 Sandcast #5084 - running
1969 CB750 Sandcast #5128 - Running
1970 CB750 next project
1975 K2 (K3-5 donīt exist in Sweden) - Running
1981 Goldwing 1100 Interstate