Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 175 & 200 Talk => Topic started by: dcX on April 16, 2017, 01:48:36 PM

Title: Serial number missing
Post by: dcX on April 16, 2017, 01:48:36 PM
My bike 175 Dual Twin is missing the serial number plate,( there are the rivet holes showing where it once was - but alas no more). This is making it difficult to order parts as I understand there were some (dynamo) changes throughout the 175's lifetime.

What I do have is the frame number TAI 25089 I would appreciate if any of you could see if your frame number is similar then let me know the serial number for that bike, I appreciate some may not want to publish their bikes identification / serial number so if you could personal message me with a serial number I would appreciate it. I'm not sure if I need the complete serial number or just the 16 & month letter?
Many thanks

Title: Re: Serial number missing
Post by: moonpup on April 16, 2017, 02:04:22 PM
Per the "Serial Number I.D. Guide" found on the site is this bit of information...

"A final note:- As the machines left the factory, the identification numbers contained within the vehicle serial, frame and engine numbers were never the same on any individual bike, but were usually within a few hundred of each other (except for the early 200cc machines mentioned previously which were built with late-numbered 175 frames). Any other machine with numbers further apart than this has probably had an engine change during its lifetime."

This means that the missing tag should be within that range. (a few hundred off from the frame number)  Also included in the guide are these numbers for the 175's....

" 16  M  22448  January  1967
  16  O   27401  March    1967"

Your bike should fit somewhere between those numbers (Jan - Mar 1967)
Title: Re: Serial number missing
Post by: dcX on April 17, 2017, 03:27:40 PM
Thanks Moonpup,

I have seen the same document you referenced, however I am looking for a new dynamo, points & condenser, the parts list says if the bike serial number is before 16 G  then use this; or if after 16 G then you need that.

What I can't do is estimate from the frame number whether the serial number would be before or after 16 G?
Any further help would be greatly appreciated.

Title: Re: Serial number missing
Post by: moonpup on April 17, 2017, 04:22:49 PM
16G is July of 1966. ( 2 bikes identified as 16G are 11761 & 12466)  Your frame number is 12,600 + past that reference range. Your bike should easily be identified as an "after 16G" bike.

Of course, this all assumes that your engine is original and not from an earlier "before 16G" bike. How close is your engine number to the frame number?
Title: Re: Serial number missing
Post by: OldSwartout on April 17, 2017, 05:33:19 PM
I understand there were some (dynamo) changes throughout the 175's lifetime.

Assuming your dynamo still is intact, you can just remove the cover and see what the points configuration is. Compare what is there against service letter BSG-0046 downloadable from this site That will also help you confirm what group of serial numbers your bike is.
Title: Re: Serial number missing
Post by: dcr on April 18, 2017, 09:29:53 AM
What is the number on the motor? Should be on the right side.
Title: Re: Serial number missing
Post by: bsracer on April 18, 2017, 10:51:03 AM
You could post up a few pics of various parts like the points configuration Karl referred to. Does the rear sprocket have 4 or 6 bolts/nuts holding it on? Oil tank under the gas tank or on the side of the bike?

Title: Re: Serial number missing
Post by: dcX on April 20, 2017, 06:14:38 PM
Thanks for the replies especially the service letters link.

I have 2 bikes both received in boxes / incomplete. I can't assume the engine covers were bolted to the correct crankcases.
1st bike does have a:-
serial number  16 O 27489
Frame TAI 27525
I have married this with engine TAI 27653

I have a dynamo which looks like the P.25, 3rd image (after 16 L dynamo) on the service letters link; which tallies with serial number above. I will replace the points & condensor as a matter of course.

2nd bike no serial number
Frame TAI 25089
Engine TAI 25155

This engine doesn't have the dynamo, I'm not concerned which type dynamo this bike ends up with as long as it works. 2nd bike is much longer term I'm trying to put some costs together for this. I'm open minded to all spark generation options with this.

Also if I could cross reference similar serial numbers to frame numbers then it may aid registering this bike later.


Title: Re: Serial number missing
Post by: dcX on April 28, 2017, 05:20:36 PM
Both bikes have 6 bolts on each rear sprocket, just the 'side panel' type oil tank. Also photo of the points (on what I believe is a 1703-8002 dynamo):-
Title: Re: Serial number missing
Post by: BRT-GTR on April 29, 2017, 08:15:33 AM
                     You will find identical points to yours were used on early KZ Kawasaki 650 and 1000 machines and are easier to source.The condensers are the same but Kawasaki used two different arrangements, inverting the condensers on certain models, just make sure the bracket is the right way up. 

              Just put new points and condensers in my GTO but instead of soldering the incoming black/white wires to the condensers, I made a simple change that will make future replacements much easier. It also avoids having to solder wires to the new condensers which can be damaged if too much heat soaks in.

           So, just cut the two tagged wires off the old condensers and while you've got the points plate out, simply solder them to the incoming black/white wires. You can then connect the new  tags on the incoming wires to the points along with the leads from the new condensers. Connect both tags to the appropriate points before attaching the points to the backplate, it's easier to tighten the 3mm screws while they are out. Finally, ensure the tags wont touch the cover plate when replaced.