Author Topic: GTR/GTO production dating mystery  (Read 6168 times)

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Offline BRT-GTR

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GTR/GTO production dating mystery
« on: September 23, 2014, 03:04:50 PM »
 This is one for Graham Weeks,
 Hi Graham,
   I've often wondered if the machine VIN, '21N'  06800 shown on your dating list is a 46 year old typing error by BS or Rockford. It stands in splendid isolation as a single 21N bike on the list with no other identified production for at least 6-8 months either side of it. It doesn't look right.  I assume you picked up this VIN from the BS Service Bulletin for the float pin mod.

     Should it have been shown as '21H'  (AUG 68) ??,  it makes more sense sequentially and the two letters are adjacent on the keyboard. It also fits in better with other reasonably reliable production dates posted on this site.  Did someone in the past simply get it wrong, the other dates on my Service Bulletin print are a bit fuzzy and not clear.   What do you think?

MODIFICATION:-  Just noticed the Service Bulletin actually says Serial No 21...6800 with the date (Feb 14, 1969). It doesn't show an 'N' but would be N based on the date.  Did BS send out this information which was then transposed incorrectly by a typist at Rockfords to produce their Service Bulletin. Who knows??

Brian the Brit.
« Last Edit: September 23, 2014, 03:57:58 PM by BRT-GTR »
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Offline disc_valve

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Re: GTR/GTO production dating mystery
« Reply #1 on: September 25, 2014, 06:19:59 AM »
Hi, Brian,

You are correct in your assumption that I got "6800" from the Dealer Service Letter. I think I must have gone down the same logic line as you in deciding it was "21N", but I do also have "21W6962" listed for Nov '69. I'm not sure where I got that one from - it miight have been from a bike advertised on eBay as I tend to harvest any numbers I see to keep the list up to date.

I do know that Bridgestone made the GTR and GTO in separate batches, with a considerable gap between them, so it's hard to be absolutely sure where "6800" came in the sequence. According to the serial numbers I have seen it could have been anywhere between July '68 and November '69, but the only sure way to tell is if anyone out there there has another 350 with numbers in that gap to help pin down the true date. the Feb '69 could indeed have been "finger trouble" when producing the Service letter.

Good call - it's now over to 350-owning site members.

Graham

   

Offline BRT-GTR

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Re: GTR/GTO production dating mystery
« Reply #2 on: September 25, 2014, 04:07:07 PM »
Hi Graham,
              Thanks for reply. I wrote up my own 350 dating list, when I rejoined the BS community 12 months ago, before I saw yours. Used the Bulletin dates and my own two machines so I could see when the various modifications were made. Could add mods to your list if you would email me a copy. Makes interesting reading, (the barrel mods were announced only 2 months after full production began and must have been planned ahead of production but they obviously had 1100 pairs of the early barrels in store, which they used.)

 I don't have an issue with 21W. Would think this was the first batch (500 or 1000 or more?) specially made for Rockfords which they would have received and sold in 1970. Now, were they all gold GTO's as suggested by 90vfr750 and Kotaro or were some GTRs included. I am sure you are familiar with the post below :-

http://bridgestonemotorcycleparts.com/index.php?topic=152.0

Were any GTRs produced after July 68? at approx 7000 machines.  New member, Sye's 1970 GTR may help solve this one (could be registration date but certainly a late one).
The latest/highest  Vin that I am aware of is 9668 on a March 1971 GTO, claimed to be one of the last built. This is a bike owned by a Dave Livingstone as reported in an article from Japanese Classic Magazine(UK), Aug 92, available on the net. Did production exceed 10,000 as you suggest on your list ??

                 Assuming approx 7000 GTRs were built to July 68, we need another 3000 machines to bring us up to 10,000.   The numbers don't quite add up at the moment.    Where are those missing bikes ?  ???    (Could there be a thousand GTOs  sat in an abandoned warehouse or containers somewhere in the US ??, I wish). :D :D :D

Brian the Brit
« Last Edit: September 25, 2014, 06:16:45 PM by BRT-GTR »
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I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

Offline moonpup

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Re: GTR/GTO production dating mystery
« Reply #3 on: September 25, 2014, 04:28:09 PM »
For what it's worth, my 2 gold/chrome GTO's are 6962 & 7032.
Confucius say... "Better to have Bridgestone than Kidneystone"

Offline slawsonb

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Re: GTR/GTO production dating mystery
« Reply #4 on: September 25, 2014, 04:49:43 PM »
Brian, stranger things have (and are) happening! If we find them I bet they all have damaged clutch covers.
 ;D :o ;D
...bert

Offline BRT-GTR

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Re: GTR/GTO production dating mystery
« Reply #5 on: September 25, 2014, 04:59:04 PM »
Hi Bert,
          .........and missing chainguards, but I could stretch to 10 machines if you do.  ;D ;D ;D

Hi Moonpup, Thanks, they were probably on the production line at the same time. Lucky you, if you ever want to sell one...........

  Brian.
« Last Edit: September 25, 2014, 05:08:14 PM by BRT-GTR »
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I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

ziggy stardust

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Re: GTR/GTO production dating mystery
« Reply #6 on: September 25, 2014, 05:34:01 PM »
Hey Brian I know where there's a GTO if you want one.

Z

Offline BRT-GTR

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Re: GTR/GTO production dating mystery
« Reply #7 on: September 25, 2014, 05:43:20 PM »
Hi Z,
        You did give me a link a little while ago but I never followed it up. Going to collect a new, to me,  GTR ( the Kent one) on Saturday. Don't think the wife's allowance would stretch to yet another at the moment.
Brian.
Unspoiled by progress.
I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

ziggy stardust

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Re: GTR/GTO production dating mystery
« Reply #8 on: September 25, 2014, 06:24:02 PM »
Oh Mick's bike, I know him very well from our Suzuki RE5 days. To be honest Brian I think there's next to nothing wrong with the engine.

If worse comes to worst and you should need a con rod kit I have one. ;)

Z

Offline BRT-GTR

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Re: GTR/GTO production dating mystery
« Reply #9 on: September 25, 2014, 06:32:42 PM »
Cheers Z,
              I know we're digressing but its my post. Crank is not moving, barrels free, primary drive free, crank bearing, cheek seal or discvalve, I guess. Knowing my luck it will be an indestructible alien craft, sucked into intake and jammed between crank and cases, it happens all the time - way up there on the 'stuckiness' scale ;D ;D

Anyway to get things back on track, Graham here's my numbers :-         21 S 00918   -   July 67
                                                                                                  21 F 06003   -   June 68  
Can also give you , seen and verified at dealers                                   21 S 00974
                                                                                                  21 S 01374
All above GTRs. Can I suggest GTOs are indicated on the list , maybe with colour if known.
                  Brian.
« Last Edit: September 26, 2014, 03:55:16 AM by BRT-GTR »
Unspoiled by progress.
I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

Offline BRT-GTR

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Re: GTR/GTO production dating mystery
« Reply #10 on: September 26, 2014, 05:05:46 AM »
Graham and Guys,
                      Thinking about this in a bit more depth, how does this sound.
 Assume 6800 was built in July 67 (probably the last one in that run), then production stopped till Nov 69, we know that. However, by late 68 BS were receiving dealer feedback about wear on the float pins. They devised an after market solution with Mikuni and issued the mod in Feb, 69, not knowing whether production would start again. Maybe, that is why the mod issue date and the machine VIN don't match up datewise, so BS left the production month letter 'H' out. It's sheer coincidence that the two possible month letters are next to each other on the keyboard. Make sense ?

Keep the VIN numbers rolling in, guys, there's not many of them on Graham's list considering how many member we have.             Brian.
                
« Last Edit: September 26, 2014, 07:50:42 AM by BRT-GTR »
Unspoiled by progress.
I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

Offline disc_valve

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Re: GTR/GTO production dating mystery
« Reply #11 on: September 26, 2014, 09:51:34 AM »
Hi, Brian,

Yes, Dave Livingstone's GTO is the latest 350 I've seen, dated march 1971. I made a guess at the total number of 350s made based on an article in a Japanese magazine which said around 10000 bikes, but i've nio idea what the last serial was - the chances of Dave's bike being the actual last 350 made is fairly slim!

On the subject of identifying GTR and GTO modesl in my list, that would sound like a good idea in retrospect. but I've lost track of the model/type of most of the bikes listed. Working from Kotaro's information, I think all we can do is make an educated guess at the batches of GTRs and GTOs - the serial numbers do seem to come in discreet batches.

Graham

Offline dcr

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Re: GTR/GTO production dating mystery
« Reply #12 on: September 26, 2014, 10:04:20 AM »
Question on the numbers: Any frames or motor cases that were stocked as parts - were they stamped with a serial number?
1966 175 DT and 1968 350 GTR

 


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