Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 175 & 200 Talk => Topic started by: CL-100 on April 14, 2019, 10:12:32 AM

Title: A question for the 175 experts
Post by: CL-100 on April 14, 2019, 10:12:32 AM
I've recently purchased a 175 lower end to have as a bench top project while I wait for parts or services on my main project.  The engine came without any history on the rest of the bike it came from, but it was so clean I thought I'd take a chance on it.  The clutch cover has the engine ID as TA1 05911.  It was represented to me as a 1966 model, but again no frame number to corroborate.  I haven't done anything with it yet except look through the parts and service manuals, which raised a few questions for me. 

From what I can tell in searching this site, it is an earlier model, but I'm guessing "not" a 16A model.  In looking through the parts manual there are several references for parts "before/after 16B, 16G, etc.  Would anyone out there have an engine ID close to the one I have and know whether their bike is a 16B, 16C, or ?

Any help is greatly appreciated.

Rowland
Title: Re: A question for the 175 experts
Post by: CL-100 on April 14, 2019, 10:42:41 AM
After my previous posting I found a notation in the Clymer service manual referencing:

...a modified fifth speed shift fork for 175 models after 16B04739.

With that, I'm speculating that I have a B or C model engine lower unit.
Title: Re: A question for the 175 experts
Post by: bsracer on April 17, 2019, 04:25:57 AM
Can you post a couple of pictures? There are differences that might be referenced to vin changes like timing gears for instance.


paul
Title: Re: A question for the 175 experts
Post by: OldSwartout on April 17, 2019, 08:16:41 AM
The 16A - 16Z serial number prefixes indicate the year and month of build. Go to the following topic:  https://bridgestonemotorcycleparts.com/index.php?topic=449.20 , scroll down to the list of 175 build numbers and compare the 5 digits of your TA1 engine number to the list. You'll  be able to tell which year & month (16A - 16Z) your engine was built.  This isn't 100% foolproof, the numbers in the post are those that have been verified and aren't a complete list.  As bsracer says, the proof is in the parts you find when you disassemble it.

That's assuming the clutch cover is original.  Most are.
Title: Re: A question for the 175 experts
Post by: BRT-GTR on April 17, 2019, 09:08:32 AM
      I was looking for Graham Weeks list when Karl posted link above. Graham listed the lowest and highest VIN known for each month of production.
       Based on the engine number being within a few hundred of the machine VIN, it could still be a B or C machine (Feb or March 66), so unless one of our members can post closer numbers I think this is as best as you can get to an actual production date..
Title: Re: A question for the 175 experts
Post by: CL-100 on April 19, 2019, 04:45:31 PM
Thanks for the responses!  Graham's running list of known serial numbers is a real treasure.  I still miss his posts.  The list seems to confirm my guess that the engine is a late 16B or early 16C.  For purposes of future parts purchasing, I think I may be OK as I haven't come across any parts difference for B and C models.   The only parts book reference that is close so far is the center crank bearing and seal, which was different for models before 16B.

I've gone ahead and posted a picture of the dynamo timing gear.  Clearly a "before 16G" version.  I've also noted that the oil pump has the "brass check valve connectors" that were fitted beginning in Feb. '66 according to the Clymer manual.

Thanks for all the help.  I'm sure I'll have more questions as I tear into it.