My new mystery shed & buried find

ewazix

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Firstly, thanks for the join, I'm from Somerset UK and have a 1971 Laverda 750 sf, 2023 BMW R1250gs and just bought a CB750KZ RC01 shed find that has me scratching my head. I've searched the web but not found the answer.

The 'story' with the bike is that it was taken off the road in 2012 when the owner passed away and it was inherited by the vendor. Tax & MOT and condition support the low 7k mileage. Although very dirty and obviously needing a full re-commission, the engine and carbs are free, there is little or no corrosion and it seems to be remarkably original. Its a black cb750 engine #RC01E-1001483 frame RC01-1001462 twin front disc, but NO STRIPES on tank or side panels, I'm told by the vendor that's original. Firstly I can't find any reference to RC01 bikes with 100 numbers, they all seem to start 200? or bikes without stripes.

Now the really odd bit, it is DVLA registered with a 78/79 'T' plate, but log book says it was first registered in 1996! This is confirmed online and its been on SORN for years. It's not recorded as an import. My research suggests this means it was either unregistered in stock from 1978/9 until 1996 when it was given an age related plate, or had been registered in a UK non DVLA territory like the Channel Islands?

Any information on the identification VIN numbers, model/stripes/region and registration mystery would be welcome please.
 

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That is, at earliest, a 1979 cb750k. The top of the engine (valve covers) are protecting a dual over head cam (DOHC) set up that started in '79. Honda's last single over head cam was '78. Not sure if that helps.
My 1981 DOHC doesn't have stripes either, but I don't know if it had been repainted in the past.
 
That is, at earliest, a 1979 cb750k. The top of the engine (valve covers) are protecting a dual over head cam (DOHC) set up that started in '79. Honda's last single over head cam was '78. Not sure if that helps.
My 1981 DOHC doesn't have stripes either, but I don't know if it had been repainted in the past.
Thank you for the reply. Yes, it's a K, the RC01 numbers suggest it's a KZ RC01, but every resource I've found including the documents on this site start RC01 engine/frame numbers from 200..., not 100.. like mine.
 
I'm not well versed in engine numbers and matching those to frame numbers. Is it important to do that?
The bike has 7k miles and appears quite original, Im looking to recommission and restore to original spec if possible, but currently cannot establish what spec and colour etc it should be. Also since the KZ RC01 100... series numbers are not listed it makes parts ordering tricky.
 
as regards the 1996 part the dvla have done similar with my japanese domestic market 750fz import. they have date of first registration 1992 which must be when it was registered by the importer or buyer, they have given it an X reg but it is a 1979 , i sent honda uk docs off to dvla with proof of year of manufacture and they got stroppy wanting to know the month it was made. i wanted to get it a 1979 reg for historic vehicle and they refused. the frame number isn't on a plate it is stamped into the headstock RC041000--- and engine RC01E4000---. there is a facebook cb750/900 group and they first of all helped me to identify the numbers and year of bike and then honda uk.
 
as regards the 1996 part the dvla have done similar with my japanese domestic market 750fz import. they have date of first registration 1992 which must be when it was registered by the importer or buyer, they have given it an X reg but it is a 1979 , i sent honda uk docs off to dvla with proof of year of manufacture and they got stroppy wanting to know the month it was made. i wanted to get it a 1979 reg for historic vehicle and they refused. the frame number isn't on a plate it is stamped into the headstock RC041000--- and engine RC01E4000---. there is a facebook cb750/900 group and they first of all helped me to identify the numbers and year of bike and then honda uk.
Thank you, that's useful I'll check that out.
 
The new twin cam CB750K was actually introduced in Europe in 1978 at the IMFA Show in Cologne Germany as well as some other events. Maybe you ended up with one of the display bikes that ended up in the hands of someone that didn't register it. It might have been passed around till it finally was registered in 1996. Long shot but possible. These twin cam engines were based off the engines Honda was racing at the time. These bikes were offered for sale in Europe later in 1978.
 
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The new twin cam CB750K was actually introduced in Europe in 1978 at the IMFA Show in Cologne Germany as well as some other events. Maybe you ended up with one of the display bikes that ended up in the hands of someone that didn't register it. It might have been passed around till it finally was registered in 1996. Long shot but possible. These twin cam engines were based off the engines Honda was racing at the time. These bikes were offered for sale in Europe later in 1978.
Interesting, thank you. What I can't understand if it was an import to the UK is why the log book does not mention it, they usually do. I've had two bikes that were imported some years ago and both carried that note on the V5.
 
Possible a different engine was put in that frame at some point? Or could it have been imported by a private owner and never recorded? Spit balling here.
 
I think the engine and frame are original, both have the unusual RC01-100.. numbers. I just can't find a document that mentions RC01 numbers starting with 100

Anybody got an RC01 with a 100... number?
Possible a different engine was put in that frame at some point? Or could it have been imported by a private owner and never recorded? Spit balling here.
 
With everybody's help, in particular Mark from David Silver Honda Spares UK it's narrowed down the KZ RC01 '100....' series numbers from their records as a Japanese domestic market model. Some web sleuthing also confirmed this with a Japanese language original workshop manual. It looks like it was a very short production run in this spec and there are few about. I've found only one example with the exact same configuration of footpeg position, rear tail/light, TWIN front discs, gold badges and a side reflector (which were apparently optional, but commonly factory fitted in Japan), this was an example sold by Bonhams ten years ago, although they were not sure of the original country of sale and speculated USA.

I have now confirmed it appears to be largely original apart from the front mudguard, which Mark points out is aftermarket (and nasty!) and the paint job / missing stripes. A close examination of the tank shows it's always been black, but has been repainted a long time ago. So I can now get on with the recommissioning and restoring it to original...... depending on what I find of course :)

Thanks again, I'm sure I'll be asking more questions!
 

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i think to be sure it started life in japan you have to have a frame number stamped on the headstock and not on a plate riveted on the frame. all the writing on the fluid reservoir tops will be in japanese as well as the chain adjustment stickers etc. the speedo should be in KMPH. my imported 750FZ has all these things as it started life in japan.
 

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ewazix these pics are off the bike . also my DVLA document has nothing about it being imported. it does say date of first registration in uk 1992 and they registered it as a 1982 W reg , i had a fight with them because they would not recognise the fact it was made in 1979 and i had sent them proof of this from honda uk. in the end i had to wait and get mot's and tax until they made it historic. DVLA a law unto themselves.
 

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i think to be sure it started life in japan you have to have a frame number stamped on the headstock and not on a plate riveted on the frame. all the writing on the fluid reservoir tops will be in japanese as well as the chain adjustment stickers etc. the speedo should be in KMPH. my imported 750FZ has all these things as it started life in japan.
Thank you for the information, more to check out 👍
 
ewazix these pics are off the bike . also my DVLA document has nothing about it being imported. it does say date of first registration in uk 1992 and they registered it as a 1982 W reg , i had a fight with them because they would not recognise the fact it was made in 1979 and i had sent them proof of this from honda uk. in the end i had to wait and get mot's and tax until they made it historic. DVLA a law unto themselves.
Thank you, yes I'm anticipating a tussle with DVLA when I come to apply for historic status, who did you contact at Honda UK please?
 
sorry can't remember a name but i had to join honda owners for them to produce the document that DVLA wouldn't accept , 35£ down the drain years ago. so i didn't renew the membership and don't have the information . Sarah Dolby on honda facebook page found my bike info before the bloomin owners club for free, but as i say DVLA are hard work .!
 
I emailed Honda Uk at info.uk@honda-eu.com for a dating certificate, to get my 1985-registered CB750F correctly listed as manufactured 1983, to enable Historic status.
They will email back to confirm if they have the info you require, at which point there is a fee for the dating cert. I then sent the cert to DVLA along with a covering letter, the old V5c and a self-addressed stamped envelope with a request that they return the dating cert afterwards.
DVLA returned everything, saying their records had been updated and that I now had to take the new V5c to a vehicle licencing Post Office to declare it as Historic taxation class - but there was nothing on the replacement V5c to say the date of manufacture!
I went to the Post Office (armed with dating cert, MOT exemption declaration and V5c) expecting an argument, the lass scanned the barcode and obviously something on the DVLA system had been altered even though there was nothing about date of manufacture on the V5c, as she just accepted it and processed the application. 2 weeks later I got the new V5c through the post with the bike now listed as "Historic" taxation class.
 
sorry can't remember a name but i had to join honda owners for them to produce the document that DVLA wouldn't accept , 35£ down the drain years ago. so i didn't renew the membership and don't have the information . Sarah Dolby on honda facebook page found my bike info before the bloomin owners club for free, but as i say DVLA are hard work .!
Thank you my friend, that's helpful 👍
 
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