Topic: Purchased a cheap CB 750 for restauration

[Teddyhoeg1982]

2021:
Update 3rd of October
Update 14th of October
Update 19th of October
Update 31st of October

2022:
Update 3rd of August

Got this very cheap. Engine turns over and it does not look too bad, though several things are missing. I plan to see if it technically is ok - and if so, prepare it for a paint job and get the missing trim pieces bag and return it to 80-90 % original condition. Don't want to end up investing a fortune. I am not so familiar with Honda CBs, so I have a bit to learn about them.





On the (Danish) registration papers it says 1976, but from what I can see this should be a K4? The first serial numbers are 24xxxxx.



Looks like everything is there. Gas tank looks very good on the inside, but the paintjob is just not my taste. Would love to bring it back to orange metallic - there is a guy in Germany that specialize in re-creating the original paint and emblems. New replacement side covers where included in a box of parts, since the original ones are very broken. If the bike turns out technically very sound, perhaps I will invest such a paint job, since the tank is in such great condition on the inside. There are also no big dents.



Assume the back shocks are not original. Also as far as I know, the 4-2 exhaust would also not be original. I do though not plan on finding an original 4-4 exhaust, since they are too expensive for this project. So I will see if it runs well with this exhaust - it seems to be in good condition.
The seat is definetely not my taste, would this be original for this model? I would prefer the more flat style.



Original headlight was included, but unfortunately all indicators are missing... But seems they are easy to find.
Front forks look like they are in ok condition, would this be the original bottoms, just painted red?



Carb choke lever looks a little odd. Otherwise things look reasonably clean.



Do not know about the wiring, looks like most of it was taken apart at some time. Former owner got in as part of a trade, so he claims he never had it started and do not know anything about it. Well...



Wiring mess, hope most of it is there. I will get a Haynes book and a workshop manual and take a look..


It is odd that it is mph here in Denmark, so must be an imported bike, or the gauges were replaced with mph. Things are not that rusted, so look reasonable. If it is really 23xxx miles, this would be very low such a machine in Denmark. Could perhaps also be 123xxx... Or maybe the gauges were replaced.



I do not know if it can be verified whether the engine is the original, since as I understant it, they would normally not be matching numbers.



This is a little weird. Would there normally be en emblem here? Looks like the frame was painted at some point of time, but at least the frame serial can be read on the other side, and matches the registration papers. It was registered last time in 1995...



Brakes do not look too good, and also does not work. Will take everything apart anyway.

Any advice or input welcome, since Honda CB is new for me. But also there is plenty of information available, which is great. I have worked on various Suzuki GS models before, which was also easy to get information about. 

[bryanj]

Complete front end is wrong as is back wheel, on us model there would be a vin plate where the paint is missing.
Europ models have different serial numbers to us which is what all the lists are based on.

[newday777]

You'll have your work cut out on that one to get to 80% or more.
Here is a good reference site to know what to get to have it correct.

http://www.honda750expert.com/

[ekpent]

Numbers show the frame is a 1974 and engine 1973. Wheels both front and rear not original,forks possible 1977-78 F models with the calipers backwards,dash lights/ignition off later model. Seat might be off a 1981 or later. Shocks not original. Choke lever correct. See if you can get it running then take it from there. Good core to make  more of a resto-mod. I kinda like the paint scheme. That bare spot on the frame neck would of had a riveted data plate.

[Teddyhoeg1982]

Numbers show the frame is a 1974 and engine 1973. Wheels both front and rear not original,forks possible 1977-78 F models with the calipers backwards,dash lights/ignition off later model. Seat might be off a 1981 or later. Shocks not original. Choke lever correct. See if you can get it running then take it from there. Good core to make  more of a resto-mod. I kinda like the paint scheme. That bare spot on the frame neck would of had a riveted data plate.

Very useful, much appreciated. That is a lot of non original parts. Will see if i may reduce my ambition level about how original it should become. Here in Denmark and Germany it is quite easy to find 750 parts, so I will look around after i can confirm that the engine is ok.

[bryanj]

As its in europe no vin/id plate also numbers are different sequence e.g. UK were ALL all K2 with K2 frame numbers but advancing engine numbers up until K6 i think

[Stev-o]

First off, welcome to the forum.

We call that bike a "bitsa", has bits from this bike, bits from that one!  Not saying that is necessarily a bad thing but does reduce the value, hence you got it cheap. This bike is 45+ years old, no telling why parts were changed out.

Get it running and move forward to enjoying a CB750!

[MauiK3]

Might want to get Hondaman's book if you plan on getting into it.
The fuel filter on the fuel line will give you fits, none should be there.
Best of luck, it's a good learner bike.

[Don R]

  Someone loved that bike, they spent a lot of effort and money on it. I would rotate the front forks to the rear caliper position and leave them on it. They may be difficult to bleed the way they are, not sure. Those forks were black on the 77-78 F super sport they came on.
  I'm a fan of resto mods, especially when starting with a modified bike.

[Teddyhoeg1982]

UPDATE 3rd of October.

Ok so here is an update from the last two weeks of hunting used parts. Many km's of driving and getting in contact with people who know about these bikes in Denmark. 
I am now missing the front and rear chrome fenders, otherwise I think I am close to only be missing small parts that I can probably pick up from CMS.
Since most of the parts on my bike where from an F2 model, I now will try to sell that stuff and get some money back.
My current frame is 1974 and engine 1973. Do not know yet if the engine will start, but also found a guy with a used engine on his shelf that I could take over, if it comes to that..
If I can make the bike functionally in nice condition, I will probably send fuel tank and covers to Menno Dek in Germany, who gave me a reasonable quote to paint it Candy Gold.

For most of the parts I scraped together, I think most are approx. correct for what would an american K4 spec. As far as I understand so far, in Europe all K3-K4-K5 shared similar specs. I do not yet understand if that means they would all correspond to a K2? I am a little confused how the Euro models should have specs in 1974.


- Got a complete front fork which I think is period correct. Top of fork tubes are not pretty, but will be covered by the headlamp brackets and rubber boots. Springs are probably shot, but I will go through to overhaul it later.


- Got the collector for the brake lines on the front fork (I do not know what this part is called in English..)
- Found the rubber strap for the battery.. 
- Front brake caliper in good condition, check. I am actually a little in doubt if this is the correct version, but it seems to fit the front fork.
- Got the handle for the rear seat. It seems this part would actually be K6, and that for K4 it should be a couple of smaller handles? But this also looks fine for now I think.
- Found the bracket for the rear light and license plate, but I think this may also be for a K6 rear fender? The light itself is a smaller Euro version, which I think may also be K6.. Glass is missing.
- Headlight chrome brackets are actually in pretty good condition, which is nice.
- Found the plastic inner mudgard for rear


- Found a set of rear struts which I think may be original and correct. Don't know about functionality of these...
- Found the small tray for under the seat..
- Got the bracket and lock for the seat. My existing key works, probably because the lock is so worn?
- Original style Iginition cover in ok condition
- Four new indicators with alu housing. I am not sure how period correct they are, but they look pretty good. Also got the front chrome arms for the indicators used, in ok condition.
- Cockpit with lights for handlebar mount seems to be correct and in pretty good condition
- Got the left mirror which may be original, but could for some reason only find a bunch of left - no matching right mirrors.
- Ignition for under tank including key, to replace the F2 cockpit that is mounted on my bike now.









- Found a seat in ok condition... Appears to have metal body. It does not say Honda on back of the vinyl and there are two small holes in the front at the fuel tank. I will probably look for a new seat cover, or maybe I will try to clean it and repair the two holes. There is a small plastic cover under the seat, which I think may be for keeping small stuff?





- I think these rims could be period correct? The chrome is not in great condition, but also not terrible. With new spokes and tires it may look ok after cleaning up the alu and chrome. Brake disc seems in pretty good condition.



- Have a set of new covers and the missing emblem ready for paint. Will be interesting if I can get the emblems off. The old covers are glued in many places.



- This stuff was included with the bike. Looks ok to me, but do not know if the brake shoes are for the F2 rims currently on the bike or they may fit the new used wheels I got. Also do not know if the gaskets are of good quality.



- Does anyone know what model those headlight brackets are from? They were included with the bike.





- Headlight is not very pretty, but I think it may be original? If so, paint and perhaps a new chrome ring could make it look good.

[seanbarney41]

Those headlight brackets are a popular aftermarket universal design.  The headlight bucket you posted is for a Kawasaki of similar vintage...correct K1-K6 bucket is plastic.

[Alan F.]

Wonderful progress, this is going to be a fun one.

[69cb750]

CB750-2400002 to CB750-2406000+ are JDM K4 models sold in Japan.
Your bike was sold new in Japan. somehow made its was to Denmark.

[grcamna2]

I like that blue paint,subscribed.

[Teddyhoeg1982]

CB750-2400002 to CB750-2406000+ are JDM K4 models sold in Japan.
Your bike was sold new in Japan. somehow made its was to Denmark.

That is interesting. I got the papers that say it was registered first time in Denmark in 1976, so two years after production.

[Teddyhoeg1982]

Those headlight brackets are a popular aftermarket universal design.  The headlight bucket you posted is for a Kawasaki of similar vintage...correct K1-K6 bucket is plastic.

Yes for sure the brackets could be reproduction.
I am surprised the correct light bucket would be plastic, but i will look for an original. Thanks.

[Stev-o]

"There is a small plastic cover under the seat"

The "doc holder" is useful, I keep my proof of insurance in there.  The owners manual would have come in it from the dealer.

That is a nice seat, I would use it.  You could paint the logo on the back.

[jlh3rd]

wheels are not D.I.D. stamped on the side so those would be correct for an original issued '75 factory wheel.

[bryanj]

One front fork tube is definately shot(deep and large pitting just above alloy slider top) and seals wont hold, its an early caliper bracket, not sure about sliders,

[PeWe]

Good idea if you can find other stock K2 bikes in Denmark to see how they look like. Maybe as the Swedish CB750 K2?

CMSNL and David Silver have not the setup for Swedish K2's that were delivered 1972-75.  Engines followed the years as the US types.

Swedish rear fender and lamp as K1, except the fender had more holes for mudflap. Tricky to find.
My K2 build got NOS K1 rear fender. Blinkers as K1 too. Grab rail, the early small one side.
Fork as the K6  (late K2 -72 and forward) except for upper tree (unicorn yoke) for the K2 gauges which is a must if your intention is to bring it back to a stock K2.
K6/ F1 gauges easier to find for not that much, different yoke and bracket.

It will be easier if you can locate some stock bikes and have a look. Bring your camera/telephone.

Most people will not see the difference if you'll use K6 parts where missing. Except for oil tank, late K2 engine cases from 1975 still have the thinner spigot for the earlier oil tank, K6 got thicker.

[BenelliSEI]

Your green face tach and speedo only came on the ‘76 K6 in North America. Probably originals to your bike. Low mileage?

[Teddyhoeg1982]

Your green face tach and speedo only came on the ‘76 K6 in North America. Probably originals to your bike. Low mileage?

My bike is a 74 from Japan it seems, so I believe the gauges would not have been green originally?

[Teddyhoeg1982]

Update 14th of October



Small update, found a set of ok looking original fenders for front and back, as well as a Euro small style rear light. Also an original chain guard and an original headlight is on its way. Further I found a set of period correct gauges with the "unicorn" triple tree which I will pick up soon.
With those remaining parts in hand, I should be close to having all parts ready to do a technical mock-up of the bike and see if it runs.. At least then it will be complete and relatively original.

[Teddyhoeg1982]

Update 19th of October



Finally recieved a correct original headlight and an original chainguard. Just missing the original gauges and triple tree, which I have schedules to pick up from a guy 30th of October. Then it will be interesting to start assembling everything and see how many small parts I am still missing...

[richmagee7]

You're pretty good at locating parts Teddy.  Looking forward to seeing how this turns out.

[desertrefugee]

You're pretty good at locating parts Teddy.  Looking forward to seeing how this turns out.

No kidding.

[Teddyhoeg1982]

Thanks for the support. Yes and also about 1200$ has so far been invested in parts, with a lot more to come. Now i need to get the engine checked soon, to see if I also need to source an engine.

[Teddyhoeg1982]

Update 31st of October 2021


Found a pair of okayish gauges. I think these are 1974 period correct? With some rust removal, polish and paint I think they will look okay for a decent overall cost.


There is a bracket that makes it quite easy to seperate the pieces of the gauges. Somehow I think not all years had this?


These tripple trees are not easy to find. This one looks ok with no cracks, but there is a broken bolt in the top, which I need to extract. It was accompanied by two re-chromed brackets which look quite good.

[PeWe]

Look OK for Swedish K2 that was actual between 1972-75.
Probably same in Denmark

USA got other gauges from 1973, model called K3 and look like our K6 except for petcock still as K2.

[Teddyhoeg1982]

Update 3rd of august 2022

So finally I got some work done to replace the wrong components to make the bike “almost correct”.
Note that the bike is a K4, but in Scandinavia this would have US K2 specifications.
I replaced wheels, forks, shocks, fuel tank, triple tree, front brake valider, seat, fenders, headlight, rear light, gauges, mirrors, side covers, ignition and some smaller stuff. Still have a set of indicators to mount, but am missing the seat bracket. Still a long way to go… Look forward to sort out the wiring and see if it will start.

[Shtonecb500]

wow, nice work!

[PeWe]

That bike reminds me about the first version of my CB750 K6 (avatar bike) at its comeback on the road 2014
A really nice feeling to ride it again after 24 years. (parked 1990)

The upgrades continued  after that and still coming. This forum is a dwell of knowledge, good ideas and other good builds!

[Teddyhoeg1982]

That bike reminds me about the first version of my CB750 K6 (avatar bike) at its comeback on the road 2014
A really nice feeling to ride it again after 24 years. (parked 1990)

The upgrades continued  after that and still coming. This forum is a dwell of knowledge, good ideas and other good builds!

Yes this was parked since mid 90's...
This bike seems to be Japan produced 1974, which is not the model sold in Denmark during that time. So it must be imported. Also first registration happened in 1978 in Denmark, so somehow it was imported then.
I am a little in doubt if I should go for correct K2 or K4 specifications. K4 would be easier, but I like the look of many things from K2 better actually.

[PeWe]

K2 speedo and tacho plus the upper triple tree are not cheap.
You need kmh speedo too that is not that common for sale either.

K2 version has different battery holder with additional electrical stuff. Only 1 fuse.
K4 different, as K6 in Europe.

But the K2 look might be tank graphics only, right?

[Bankerdanny]

I wish I had seen this sooner. I know you are trying to get back to something closer to original spec, but you could have retained the superior twin disk front end and still used the wire wheel that you have on it now. With the forks properly installed with the calipers in the back, you can use CB500/550 rotors with the standard wire wheel (the hub is already set up to have 2 rotors) and then just need to shim the calipers a bit to get them properly centered. I upgraded my single disk 750F to dual disks this way. Here is a picture. I have Lester rims, but the spacing is exactly the same as the wire wheels. Strip the black paint off the lowers and they would look very similar to the original fork.

[grcamna2]

I wish I had seen this sooner. I know you are trying to get back to something closer to original spec, but you could have retained the superior twin disk front end and still used the wire wheel that you have on it now. With the forks properly installed with the calipers in the back, you can use CB500/550 rotors with the standard wire wheel (the hub is already set up to have 2 rotors) and then just need to shim the calipers a bit to get them properly centered. I upgraded my single disk 750F to dual disks this way. Here is a picture. I have Lester rims, but the spacing is exactly the same as the wire wheels. Strip the black paint off the lowers and they would look very similar to the original fork.

Which year 750F is this one Danny ?