Mistery CB750F or K?1974 or 1978? I need help!

[Pokernico]

Hi everybody, I'm new here in the forum, I'm Italian but I live in Mexico; I need your help because I felt in love with a CB750 (see picture , I know there still is a lot of work to do ) but there's a problem and I don't know what to do.
Basically the papers say that it is a 1974 HONDA CB750F (CB F did not even exist in 1974) but the frame number is from a 1978 CB F, the frame number on bike and papers match, simply it is not from 1974 as reported.

The Bike papers are the 1999 import invoice from US to Mexico.

On contrary, the engine is a CB K from 1974 according to its serial number (different from the frame one and not reported on papers).
So I have a 1978 CB F frame with a 1974 engine, while the papers report a 1974 CB F with frame matching numbers: what do you think?Should I buy it or I could get into problems?

 

[BAHNST]

Hi;
My general thoughts are:
I would think that if the papers match what's on the bike, ie frame and/or engine numbers it will not be a issue to register it/show ownership.
Many places only record either the frame or engine number.
Having said that local laws (Mexico) will dictate if you will have red tape (problems) to sort out...e.g. Locally they might deem it a "modified vehicle" even though it "essentially the same engine" and frame through the years...
By essentially the same I mean the later F frame had different tube diameter/lengths from memory.

Maybe other members who lived in Mexico will be more help.....

Good luck

edit:
In Australia (Vic specifically) putting in another engine that isn't identical/a original factory option makes things more complicated as its classed as "modified" and you need an engineers certificate costing up to a few thousand dollars.....you need to check local laws....

 

[Pokernico]

Hi, thanks for your answer, in Mexico, from what I know (I live here since only 3 years) the main document is the invoice of when you bought a car or a bike, If you buy an used one, the owner will give you the original invoice (or a copy when original is not available) and you will fill with him a private paper that say "Mr X buy this bike from Mr Y for the amount of $xxxx date, sign" and that's it.
The document of this bike is the import invoice from 1999, so, the bike entered in Mexico with that frame and numbers and Mexico reconized it as a legit one, probably is not easy for someone at the custom to realize this problem frame number/year.

4 more questions, didn't know the frame tube diameter was different, could it be a problem for a 1974 engine?To me it looked pretty well fixed.

Would it be difficult to find in the future a buyer with this kind of problem?Should I sell as a 1974 as from papers or as a 1978 as from frame?

Would it be easy to find spare parts?There are some problems with carburetors

The guy that sell it just lowed the price and I could buy it for $1800USD, do you think it's a good deal?

Thanks

 

[dirtdigger]

Not sure what you mean about the frame tube diameter being different? Mine are all the same size...

In the US the frame is what is titled because the engine is removable and has different serial number from the frame. If the engine case is damaged beyond repair and has to be replaced then the serial number would no longer be valid on the title, thus the frame is title as engines are a replacable/wear item that may not be with the bike its whole life.

Parts are very easy to find. Carb parts are available from cb750supply.com, 4into1.com and other places depending on what is needed. Everything can be found easily in the US not sure how in Mexico.

$1800 is a pretty good deal as long as the engine is in decent running shape mechanically. If it has engine problems then it is not a good deal.

 

[Pokernico]

Hi dirtdigger,
I was refering to this state by BAHNST in his previous message "later F frame had different tube diameter/lengths from memory." so I was asking, I have no idea about.

The engine turns on, all speeds work, clutch looks good, they recently opened the engine head and registered the pistons position.

But, I'm not a magician and the bike is pretty old so, you never know.

Thanks for the links and tips, know I'm between this CB750F (or K?) that I love but with this frame/year problem and a lot to work to to and a 1978 Suzuki GS750 that has everything right, documents are ok, conditions are much better, basically nothing to do except cafe' racer conversion plus, the price is lower, $1700usd and probably could be a little less. I won't post a picture of the Suzuki in respect of this forum.

 

[BAHNST]

Re the frame...i am happy to be corrected...the engines are easiliy interchangable..i VAGELY thought I remember some differences around the steering head and backbone.....
Havent had a Sohc apart for a while.

Edit: I did find this forum discussion on frames for interest tho' this is secondary to the main focus of the original post (being "mismatched" engine and frame).
I do not guarantee the content of the linked thread tho.....
http://forums.sohc4.net/index.php?topic=19753.0

 

[Pokernico]

I was thinking about the frame/year problem, let's imagine in 1974 I buy a CB750K , in 1978 I have an accident and I destroy the chassis but not the engine, I buy a newCB750F chassis with a different serial number and I put the 1974 engine on it, then I change the papers/documents to match with the new serial number.
Could it be possible?

 

[dirtdigger]

The new frame would come with its own title, you wouldnt use the title of the wrecked frame because it is now wrecked and no longer a vehicle.

 

[Pokernico]

Yes, this could explain a 1974 engine with a 1978 frame, in the documents I would cancel the 1974 original and destroyed frame number for the new 1978 frame, right?

 

[dirtdigger]

More than likely it was just pieced together because the guy didnt have a complete bike or the 78 had a bad motor and he just found a different motor. Its done all the time, its not a big deal.

 

[Pokernico]

I understand, but in that case we would have a 1978 frame with 1978 as year on papers/documents but with a 1974 engine, not a 1978 frame with 1974 documents

 

[dirtdigger]

Well I guess do what you like. If you like the bike buy it, if you have concerns move on. Looks like a decent bike from photos, if there was a licensing issue im sure it would have shown itself by now in Mexico. If its can be licensed there whats the issue???

 

[Pokernico]

You're right, the only problem in my mind is that this kind of bikes are for people that have a great passion and who knows what they are looking for, so my fear is that this frame/year problem could be a great issue to those people if one day I decide to sell it.

 

[BAHNST]

You're right, the only problem in my mind is that this kind of bikes are for people that have a great passion and who knows what they are looking for, so my fear is that this frame/year problem could be a great issue to those people if one day I decide to sell it.

If you are going to buy it for investment....maybe avoid
If you are aiming to restore to concourse condition....maybe avoid
If you are going to keep it for a few years....and have set a budget for what you will do...consider it.....you'll enjoy the bike.
If its been licenced before in Mexico...then you have little to b concerned about in that regard ..
Thats my take on it....others may differ......
Maybe if you are already considering resale value.....you might need to take a step back and see what else is on the market

 

[Pokernico]

Hi, thanks for the message and all suggestions, I would like to get an opinion because I'm between 2 bikes, this Honda CB750X and a Suzuki, I don't know if I can post a picture of a suzuki or other brands, since this is a dedicated forum, if the amm. or a moderator say that there's no problem, I'll post some pictures to get an opinion from you an maybe others here in the forum.

 

[BAHNST]

The CBX750 is rarely offered for sale...here at least...local Honda Techs tell me its a good bike...but youll need to be confident its mechanically sound.Imho...if its mechanically sound if you buy it...youll keep it.
What Suzi??.....

 

[BAHNST]

An afterthought...google common problems on the models you are considering...that will give you a prompt bout what to look for..
E.g. if its cam chain tensioners....listen for telltale rattle.
Edit...sorry moderators if these comments are out of line.....do we have an " off topic " forum thread here??

 

[Pokernico]

I post a couple of pictures of another Honda CB from 1977 I think a 750cc (black and gold one) for sale now near were I live, I would change colors, cut the tail10/15cm and change seat, they ask $2900usd but I think you can take it for $2500usd, and then there's another one for $2700usd (orange one) also with some changes to do.

 

[verdeva]

both appear to be f models with the accelerator pump carbs. from pics, the black one appears to be the one with better maintenance. blackie is weird though, with wrong tank and gold wire wheels, no f model came with in 77 that i know of. f models were the best engines after some of the real early ones.

 

[verdeva]

The CBX750 is rarely offered for sale...here at least...local Honda Techs tell me its a good bike...but youll need to be confident its mechanically sound.Imho...if its mechanically sound if you buy it...youll keep it.
What Suzi??.....

in my book by wyatt, original honda cb750, there is no mention of a cb750x.