Topic: Thinking about buying my first CB750

[ThatUnknownGuy]

Looks like a good place to start. It's mostly there and ready to go.
I'm thinking a 74, maybe.
Hopefully the tank is not full of bonds.
Side cover wings are facing the correct way!!
Master cylinder is missing the boot at the connection.
Bars have the wires on the outside, at least I think that's what I saw.

Bar has definitely been changed, they are a replacement and that is written on the vehicle title itself.
That was a good catch, i didnt see anything wrong the first time.

K vs F

Thank you very much, i now see my original idea is not viable.

Can you go to the shop and inspect the bikes?

Do you feel comfortable buying a Project bike? Do you have mechanical skills and basic hand tools or have a friend with such?

Project bike is what Im after to be honest. I do own around 20 motorcycles and have mechanical skills but only on two strokes really

Cleaning carbs, diagnosing eletrical problems isnt the issue to me, what scares me is tinkering with the top-end. If work is needed there i'll just take it to a professional.

If you have 20 two-strokes, you have nothing to fear on working on a SOHC!  Most likely, you will only need to service the elec and fuel system to get that bike running.

What bikes do you have?  I have a few two-strokes as well, Kawasaki, Yamaha, Suzuki etc...

I should've explained myself better, they're two strokes but they're all ranging from 50-125cc, nothing major.
They're mostly what you'd call mopeds in the states, although they reach around 50'ish mph fairly easily. They're very popular in Portugal, brands like Zundapp, Kreidler, Sachs, etc. (i dont think these ever made it to market in the US).


Thanks to everyone for their comments and help.
I have bought the bike and also ordered a new copy of Hondaman's book.

Can't wait to get it delivered
Since I'll be asking for a period correct license plate, this process takes around a year, so I'm not getting it on the road anytime soon.
I'm thinking of buying some basic items for when it arrives, which would be:

• 10W40 oil
• Fuel filter
• Spark plugs
• Air filter
• Unsure about spark plug boots, i guess i'll wait and test those before commiting to buying new

Would you recommend I buy anything else?

[newday777]

Congratulations on your purchase.
Warning: use 20w50 above 21c/70°F or you will cook the valve guides.

[Stev-o]

Looks like a good place to start. It's mostly there and ready to go.
I'm thinking a 74, maybe.
Hopefully the tank is not full of bonds.
Side cover wings are facing the correct way!!
Master cylinder is missing the boot at the connection.
Bars have the wires on the outside, at least I think that's what I saw.

Bar has definitely been changed, they are a replacement and that is written on the vehicle title itself.
That was a good catch, i didnt see anything wrong the first time.

K vs F

Thank you very much, i now see my original idea is not viable.

Can you go to the shop and inspect the bikes?

Do you feel comfortable buying a Project bike? Do you have mechanical skills and basic hand tools or have a friend with such?

Project bike is what Im after to be honest. I do own around 20 motorcycles and have mechanical skills but only on two strokes really

Cleaning carbs, diagnosing eletrical problems isnt the issue to me, what scares me is tinkering with the top-end. If work is needed there i'll just take it to a professional.

If you have 20 two-strokes, you have nothing to fear on working on a SOHC!  Most likely, you will only need to service the elec and fuel system to get that bike running.

What bikes do you have?  I have a few two-strokes as well, Kawasaki, Yamaha, Suzuki etc...

I should've explained myself better, they're two strokes but they're all ranging from 50-125cc, nothing major.
They're mostly what you'd call mopeds in the states, although they reach around 50'ish mph fairly easily. They're very popular in Portugal, brands like Zundapp, Kreidler, Sachs, etc. (i dont think these ever made it to market in the US).


Thanks to everyone for their comments and help.
I have bought the bike and also ordered a new copy of Hondaman's book.

Can't wait to get it delivered
Since I'll be asking for a period correct license plate, this process takes around a year, so I'm not getting it on the road anytime soon.
I'm thinking of buying some basic items for when it arrives, which would be:

• 10W40 oil
• Fuel filter
• Spark plugs
• Air filter
• Unsure about spark plug boots, i guess i'll wait and test those before commiting to buying new

Would you recommend I buy anything else?

There was a  Sachs G3 that I wanted to buy for my daughter years ago but I ended up buying her a S65 Honda. Do you have a G3?

https://www.bike-urious.com/1980-sachs-g3-5051d/

Your list looks good, I would also buy an oil filter and the spark plug boots, unless you would rather wait and ohm them out?   I would also recommend points and condensers, but who knows, it could have electronic ignition? And of course you will need a battery [these bikes wont provide spark w/o one]

Be sure to start a thread in the "Project Shop" area of this forum once you get it so we can follow along and answer questions.

Congrats and welcome to the SOHC Honda Club!

[ThatUnknownGuy]

Congratulations on your purchase.
Warning: use 20w50 above 21c/70°F or you will cook the valve guides.

I do see Honda recommends 10w40 or 20w50, but everything I read says to run 10w40 unless it's a very hot climate, which is not really the case where I live.

There was a  Sachs G3 that I wanted to buy for my daughter years ago but I ended up buying her a S65 Honda. Do you have a G3?

https://www.bike-urious.com/1980-sachs-g3-5051d/

Sadly no, those werent popular at all in Portugal back in the 70/80s. Since we had a special rule about not needing a drivers license for 50cc mopeds, and also no power restriction, we had models with kickstarters, around 5-7 horsepower, etc. Those style of "slower" mopeds werent sold here sadly

Your list looks good, I would also buy an oil filter and the spark plug boots, unless you would rather wait and ohm them out?   I would also recommend points and condensers, but who knows, it could have electronic ignition? And of course you will need a battery [these bikes wont provide spark w/o one]

Be sure to start a thread in the "Project Shop" area of this forum once you get it so we can follow along and answer questions.

Congrats and welcome to the SOHC Honda Club!

I will start a new thread once I get her in  I will buy a new oil filter obviously, I wrote fuel filter instead 
Regarding the spark plug boots, I'll ohm them out first. Points/condensors wise, that's something I'll have to take a look at first as I'm fairly certain I'd be able to get them cleaned first and see if they're working fine previous to any replacement.

Regarding the battery, I know the original is the Yuasa 12N14-3A, but are there any newer alternatives? Like AGM or sealed batteries?
I have found a couple but the polarity is the other way around, im not sure if flipping the battery would be enough as I'm not sure about the slack on the cables

[Stev-o]

Yuasa makes very good batteries but I prefer sealed AGM so no spilled acid.  I've bought Scorpion and Mighty Max recently, I dont know if those are available to you?

https://www.amazon.com/dp/B01GEVSUJ6?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1

Get the correct battery, there is no slack in the cables.

[Bodi]

A bike from someone with a collection of them, that has several non matching parts for its stated model and year. Plus oddities like the serial number location.
To me it looks like the collector had a shed full of parts and put together a few bikes to sell. Maybe just for the money, maybe to get rid of parts not needed with a bonus bit of dosh?
This brings some worries for me. Why three at once - and does this cheapest one have the more worn or defective parts?
For a 50 year old bike with unknown provenance the speedometer mileage means nothing.
"Ran when put away" - 14 years ago - yeah. That story has been told too many times and although often true it leaves a lot of questions unanswered. Ran great or barely ran? Started once to see if it would, or was it a daily ride up to its last day?
Was it prepped for long term storage? Stored inside a heated space, unheated shed, covered outside, or parked open to the weather?
Personally I would wait for one with fewer questions.

[ThatUnknownGuy]

Yuasa makes very good batteries but I prefer sealed AGM so no spilled acid.  I've bought Scorpion and Mighty Max recently, I dont know if those are available to you?

https://www.amazon.com/dp/B01GEVSUJ6?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2&th=1

Get the correct battery, there is no slack in the cables.

I cant get those specifically, but since thats a standard YB14L battery, I can find plenty of options locally. Thank you.

A bike from someone with a collection of them, that has several non matching parts for its stated model and year. Plus oddities like the serial number location.
To me it looks like the collector had a shed full of parts and put together a few bikes to sell. Maybe just for the money, maybe to get rid of parts not needed with a bonus bit of dosh?
This brings some worries for me. Why three at once - and does this cheapest one have the more worn or defective parts?
For a 50 year old bike with unknown provenance the speedometer mileage means nothing.
"Ran when put away" - 14 years ago - yeah. That story has been told too many times and although often true it leaves a lot of questions unanswered. Ran great or barely ran? Started once to see if it would, or was it a daily ride up to its last day?
Was it prepped for long term storage? Stored inside a heated space, unheated shed, covered outside, or parked open to the weather?
Personally I would wait for one with fewer questions.

I understand your point completely.
Regarding the serial number, there's no oddity, its the way german models came, they still have the VIN on the steering column and an extra VIN tag on the downward tube. Everything is at it should be for a German model.
I've been waiting for some years now, it's not easy to find something under this price point and from a dealer, which is a plus when importing these old bikes, due to the import process.
I dont think I'd find anything better really, I know some parts are miss matched but the reality is, waiting for the perfect bike wouldn't be feasible. I'm happy with the purchase, let's see how this goes

[MauiK3]

Good bike to start with.
A reminder, these bikes can be an addiction and don't count on making money with one, it only happens rarely, like with sandcast versions that are purchased inexpensively and kept mostly original.

[ThatUnknownGuy]

So today my extensive reading let me down the rabbit hole that is "which oil to run".

Let's start by saying that I've read HondaMan's comments about the translation errors of the manuals, and that 20w50 should be used instead of 10w40 in my climate.
We usually get over 15celsius/60F all year round, around summer time 30celsius/90F or more, so i think 20w50 is more adequate.

After reading that chunk of information I come across the issue of newer oils not having enough Zinc in them.
Sadly in Europe there's not as much choice as in the US, so I was thinking of running Motul 5100 or Castrol Power 1 (both in 20W50 and naturally JASO MA2 compliant).
Maybe someone in Europe can give me some feedback on a good oil without starting a new thread? 

What about a first flush? That oil will be 14years old at least I'd say.
I was thinking about buying a cheap 15W40 diesel oil as recommended in the forum, and letting it idle for 10-15 minutes, and then putting the good oil in.

My plan:

• Take out old oil and filter
• New oil filter
• Cheap 15W40 diesel oil
• Let it run for 15 minutes
• Take out oil and filter again
• Another new oil filter
• Good 20w50 oil

Does this sound like a solid plan?

[carnivorous chicken]

Don't see that anyone has mentioned this, but CMS in the Netherlands has a lot of vintage SOHC stuff, similar to David Silver Spares in the UK, and they're in the EU. They're frequently referred to as CMSNL. They've got parts fiches with lists of available parts -- you can just google them to find them. Not sure how much 750 stuff is there -- I've had a few but not lately, mostlye 350Fs and 550s.

e... Bem-vindo. Falo um pouco de português porque trabalho em um país que era uma colônia portuguesa, Timor-Leste. Agora moro na Cidade do México, então meu português é mais como... portuñol.

[kyle750]

My plan:

• Take out old oil and filter
• New oil filter
• Cheap 15W40 diesel oil
• Let it run for 15 minutes
• Take out oil and filter again
• Another new oil filter
• Good 20w50 oil

Does this sound like a solid plan?

Congratulations on buying your CB750.  I really like the look of the bike. 

You were in a very similar situation to me in Thailand.  Not many bikes for sale and they were either restored with huge prices or fixers. Buyers in the USA have a big advantage as there are many CB750s for sale to choose from.  It took a long time until I found my CB750 - it was running but needed a lot of cosmetic work and replacement parts.  Not everyone will agree with some of the choices made by  the previous owner but IMO your bike cosmetically is in good shape. A huge plus considering the high prices for many CB750 parts. 

I noticed your plan includes running the bike for 15 minutes.  Are you that confident the bike will start up?  If you get it started remember it is air cooled and if stationary perhaps set up some fans to help with the cooling.

Let the fun begin 

[ThatUnknownGuy]

Don't see that anyone has mentioned this, but CMS in the Netherlands has a lot of vintage SOHC stuff, similar to David Silver Spares in the UK, and they're in the EU. They're frequently referred to as CMSNL. They've got parts fiches with lists of available parts -- you can just google them to find them. Not sure how much 750 stuff is there -- I've had a few but not lately, mostlye 350Fs and 550s.

e... Bem-vindo. Falo um pouco de português porque trabalho em um país que era uma colônia portuguesa, Timor-Leste. Agora moro na Cidade do México, então meu português é mais como... portuñol.

Yeah I've been browsing a lot on CMSNL, thanks for the heads up.
Your portuguese is pretty good 

Congratulations on buying your CB750.  I really like the look of the bike. 

You were in a very similar situation to me in Thailand.  Not many bikes for sale and they were either restored with huge prices or fixers. Buyers in the USA have a big advantage as there are many CB750s for sale to choose from.  It took a long time until I found my CB750 - it was running but needed a lot of cosmetic work and replacement parts.  Not everyone will agree with some of the choices made by  the previous owner but IMO your bike cosmetically is in good shape. A huge plus considering the high prices for many CB750 parts. 

I noticed your plan includes running the bike for 15 minutes.  Are you that confident the bike will start up?  If you get it started remember it is air cooled and if stationary perhaps set up some fans to help with the cooling.

Let the fun begin 

I am not confident it will start up, before any of that takes place I'll be cleaning and rebuilding the carb and whole fuel system, flush the tank, clean petcock etc.
Then move to engine, remove spark plugs, check cylinder walls, put a bit of oil in it and spin it by hand.
Clean points, check timing, and if it all looks ok, I'll follow the steps I've listed previously.

And yes I'll point some fans at it 

[jlh3rd]

keep the original Keihn carb internals, stay away from the aftermarket .

[Stev-o]

So today my extensive reading let me down the rabbit hole that is "which oil to run".

I use Shell Rotella diesel, not sure if it if available there?  Before making a plan to change the oil multiple times, I would drain it and see what it looks like. If the bike was stored indoors, which it appears like it was, the oil may look fine and 1 change may be all that is needed.

[MauiK3]

Maybe attempt to start it before all the work, that way you will eliminate some possibilities as to whether a non start is something you did or something else. One step at a time.