Topic: NewBie 1969 Honda CB750 project

[WaterBuffalo]

To start it off, I bought this motorbike from a Viet Nam Vet earlier this year and planned to work on it over the winter. I got it for $500 that came with a parts bike.
Having experience with motorbike before, to me this bike is in a good shape. The owner let it sat in the garage for year before I took over. Unfortunately the engine is seized as the owner said it wasn’t when he putted away. Through communication in person with him, I trust this man. I assume it is just because of the oil hasn’t been drained and long time hasn’t been running so the engine seizes.

Making this post is a way for me to keep the passion with this project alive and to learn from other people.

The first step in my plan is to strip down the bike and inspect the engine so I can unseized it.

Please let me know what you guys think, any recommendations on how I should tackle this project, tips and tricks to work on a project like this alone. Much appreciated.

Pictures attached below. Can someone teach me how to uploads the picture directly on the post rather than attaching. Thank you

[754]

 I don't think its a 69. If the frame is, you can sell it.
 Motor can probably be freed up without disassembly.

[SOHC4 Cafe Racer Fan]

The bike is far from original, but you should be able to free up the motor without complete disassembly.  What do you want to do with it? Restore it? Ride it as is? Modify it more?

[WaterBuffalo]

I don't think its a 69. If the frame is, you can sell it.
 Motor can probably be freed up without disassembly.

hm... so the registration of the motorbike said 1969, but the frame doesn't have its ID number that I can cross check. This is definitely my mistake as a buyer. *lesson learned*. The owner said as I was old, vintage bike, it doesn't require title as title didn't exist in its time. But I have the bill of sales though, from the original owner down to this man, and from this man down to me
For now, how can I get this thing on the road legally?

[WaterBuffalo]

The bike is far from original, but you should be able to free up the motor without complete disassembly.  What do you want to do with it? Restore it? Ride it as is? Modify it more?

For now I just want to unseized the engine and get it running.
I have tried to put some Marvel Mystery Oil into the spark plugs but it didn't work. It seems like the oil was leaking out from the exhaust area too.
Any recommendation?

[PeWe]

Later carbs, head, fork lowers. At least late K2, K3 or newer.

[BenelliSEI]

Even if the VIN tag is missing, the frame number should be stamped on the opposite side of the tag. Can you read it?

[calj737]

And the motor ID number is stamped on the cases, below the carbs. VIN is engraved on steering neck, behind headlight, right side as you look at bike.

[Bankerdanny]

I wouldn't be too concerned. $500 isn't a bad price even without the title. What state are you in? Rules vary from state to state regarding titles.

[Stev-o]

The bike is far from original, but you should be able to free up the motor without complete disassembly.  What do you want to do with it? Restore it? Ride it as is? Modify it more?

For now I just want to unseized the engine and get it running.

Any recommendation?

The motor most likely is not "seized", that term typically describes a motor that has had a mechanical failure.

Your motor is prolly "stuck", this happens when the motor has not turned over for a period of time and the rings rust to the cylinder, many of us have bought bikes like this, very common.

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

[scottly]

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

Stev-o, you forgot about the warning that when the motor does suddenly unstuck, there will be jets of ATF/acetone from the spark plug holes. IIRC, you have the distance record??

[WaterBuffalo]

I wouldn't be too concerned. $500 isn't a bad price even without the title. What state are you in? Rules vary from state to state regarding titles.

I live in NY state right now. Do you have any idea of how to get this thing running legally? any papers work that I can do (I have the registration and bill of sales. *the motorbike is missing the Vin tag itself*)

[WaterBuffalo]

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

Stev-o, you forgot about the warning that when the motor does suddenly unstuck, there will be jets of ATF/acetone from the spark plug holes. IIRC, you have the distance record??

The bike is far from original, but you should be able to free up the motor without complete disassembly.  What do you want to do with it? Restore it? Ride it as is? Modify it more?

For now I just want to unseized the engine and get it running.

Any recommendation?

The motor most likely is not "seized", that term typically describes a motor that has had a mechanical failure.

Your motor is prolly "stuck", this happens when the motor has not turned over for a period of time and the rings rust to the cylinder, many of us have bought bikes like this, very common.

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

Thank you both. I will give it a try since it is very hard to do all the lifting by myself. I live in Upstate New York and it is freezing cold right now. Do you think I should wait till the weather warmer and give this solution a try?
And also I have tried to use Marvel Mystery Oil before and it seemed like there were some leaking out of the exhaust area (where it contact with the engine) is this normal?

[Stev-o]

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

Stev-o, you forgot about the warning that when the motor does suddenly unstuck, there will be jets of ATF/acetone from the spark plug holes. IIRC, you have the distance record??

Hey Scottly...no, I didnt forget, I like the newbies to have a little surprise! 
And, yes, I believe I do have the record at 17'!

WaterB - I would start the penetration process now, you cannot do it too long.
Did you look for the VIN on the side of the steering neck?
I've bought a couple bikes from NY, they didnt title them back then, do you have a transferable registration? If yes, that will work.

[MauiK3]

Rear brake pedal looks odd. Big upswing, I wonder if it’s bent.
Carbs and front fender are post K0 for sure.
Tank and seat and taillight are

[BenelliSEI]

Did you find the frame number in the left side  (sitting on the bike) of the head stock? The instrument cluster is from a 1969-72 bike. Also, the oil tank has a smooth finish. Unless it’s been smoothed with body filler prior to painting, it’s 1969 or ‘70. The later ones all had recesses for the side panel badge pins/clips. The frame number will tell all! Let us know.

[lash]

Idiot lights are a 72, gauges are at least 73 or newer, frame has the helmet holders on the rear bracket, so it is at least a 72...

[WaterBuffalo]

And the motor ID number is stamped on the cases, below the carbs. VIN is engraved on steering neck, behind headlight, right side as you look at bike.

Even if the VIN tag is missing, the frame number should be stamped on the opposite side of the tag. Can you read it?

Did you find the frame number in the left side  (sitting on the bike) of the head stock? The instrument cluster is from a 1969-72 bike. Also, the oil tank has a smooth finish. Unless it’s been smoothed with body filler prior to painting, it’s 1969 or ‘70. The later ones all had recesses for the side panel badge pins/clips. The frame number will tell all! Let us know.

I suggest you remove the spark plugs, mix up a "cocktail" of 50/50 Acetone/ATF and pour a couple oz in each bore. Let it penetrate for 24hrs or so and then put the bike in 4th gear and rock it back and forth, the motor should "unstuck".
If yes, great, if no, repeat.

Good luck.

Stev-o, you forgot about the warning that when the motor does suddenly unstuck, there will be jets of ATF/acetone from the spark plug holes. IIRC, you have the distance record??

Hey Scottly...no, I didnt forget, I like the newbies to have a little surprise! 
And, yes, I believe I do have the record at 17'!

WaterB - I would start the penetration process now, you cannot do it too long.
Did you look for the VIN on the side of the steering neck?
I've bought a couple bikes from NY, they didnt title them back then, do you have a transferable registration? If yes, that will work.

Sorry for slow response guys as I am busy with work and school. But I am much appreciate your helps.
As your recommendations, I look for the frame number and unfortunately it was wear down badly as I barely able to see the first number
But I found the engine number though. Will that helps?
Engine number is: CB750E-235225
My goal with this project is to have a Honda CB750 to ride down the street. So I don't really care about its production year so much. Hope you guys won't upset for this as I know some people really care about its history and would like to restore it to its original shape.
For now, my number one concern would be unseize the engine (Stev-o has gave me a recommendation and I will try it soon) and do the paper work for this motorbike.
Please let me know what I can do to get this motorbike down the street legally *without Vin Tag and without visible Frame number*
Much appreciate

[Johnie]

That engine number indicates it's a 1974 motor. Someone could have put this 74 motor into a different frame, but without the frame number you won't know. Not a big deal. Maybe the previous owner could tell you. This is your bike so do with it what you want. Now if it was a 69 sandcast or 70 KO you were going to chop up then the board would probably try to kindly persuade you to restore it. But this looks like a nice project for you to get your first taste of the CB750. We are here to help and answer questions so don't be shy

[Don R]

Your registration should have the frame number on it, it will start out cb750-XXXXXXX,  X being the unknown numbers. It may have just been painted over on the frame neck.  The frame number may be within a few hundred of the engine number. They never match and if it's way off it's no big deal, just indicates an engine swap.  It looks like a fun project.  Enjoy it.

[Gurp]

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Great start man!

[Bankerdanny]

That engine number indicates it's a 1974 motor. Someone could have put this 74 motor into a different frame, but without the frame number you won't know. Not a big deal. Maybe the previous owner could tell you. This is your bike so do with it what you want. Now if it was a 69 sandcast or 70 KO you were going to chop up then the board would probably try to kindly persuade you to restore it. But this looks like a nice project for you to get your first taste of the CB750. We are here to help and answer questions so don't be shy

The engine swap isn't a big deal, but there is no reason at all for the engraved VIN on the neck to be worn down. Nothing touches that part of the frame. I get after that with some paint remover and a wire brush to see if you can get it readable. IIRC the Vermont title route requires and inspection and the local cops might have a problem with an obscured frame VIN if they think someone tried to grind it down.

[Stev-o]

 there is no reason at all for the engraved stamped VIN on the neck to be worn down....

Unless it is stolen!

[Johnie]

Agreed...hopefully that frame number is just caked full of dirt. Try some WD40 which is basically a solvent to clean the area good and see what you find. Maybe use a tooth brush if it's hard to reach.

[scottly]

Many years ago I bought a 1953 BSA 650 basket case. The PO had done some smoothing with bondo on the frame, and as I was mostly interested it getting it running and on the road, I rattle-canned the frame over his work and got the bike running and registered.
A couple of months later, I got pulled over by a CHP, who noticed there was no VIN stamp on the frame. I thought I was in deep #$%* as he walked back to the cruiser and got on the radio, so I took my pocket knife and started scraping the paint and bondo off the area where the cop said the number was supposed to be. To my relief, the numbers were there, intact, and the cop sent me on my way.