Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 350 Talk => Topic started by: davis on February 09, 2018, 01:40:31 PM

Title: What's This Part?
Post by: davis on February 09, 2018, 01:40:31 PM
From my collection of bushings these two odd ones popped up. Why the raised section? Looks like they were to mate with a groove in the driven sprocket. Just curious.

- Bob
Title: Re: What's This Part?
Post by: OldSwartout on February 09, 2018, 03:55:17 PM
I believe they are the rear wheel drive dampers for a 350. There is a groove in the back of the sprocket to align the dampers.  P/N 7319-9000 (6 required).
Title: Re: What's This Part?
Post by: davis on February 09, 2018, 07:35:33 PM
Appreciate your response Karl, but all the other dampers I have and have seen do not have this raised part and all the driven sprockets I've seen are flat on both sides. These look like the were designed to fit into a circular groove on one side of the sprocket, thus why I am puzzled. Hate to pitch odd parts that may be actually unique ones useful to complete a set and mating sprocket from some sort of vintage.
Title: Re: What's This Part?
Post by: paul on February 10, 2018, 09:15:33 AM
Are you sure theyre BS parts?
Title: Re: What's This Part?
Post by: OldSwartout on February 10, 2018, 11:00:30 AM
Appreciate your response Karl, but all the other dampers I have and have seen do not have this raised part and all the driven sprockets I've seen are flat on both sides. These look like the were designed to fit into a circular groove on one side of the sprocket, thus why I am puzzled. Hate to pitch odd parts that may be actually unique ones useful to complete a set and mating sprocket from some sort of vintage.
  You're right, those aren't BS350 (see attached photo of 350 parts).  I know I've seen that exact setup with the groove in the back of the sprocket, but at this point I have no idea where.
Title: Re: What's This Part?
Post by: bsracer on February 10, 2018, 12:09:49 PM
I believe they are for the 175's . I have both types, with and without raised section. I have plenty of sprockets with a groove. The flat ones work just as well.  I used the flat ones with sprockets I had made without the groove.


paul
Title: Re: What's This Part?
Post by: davis on February 10, 2018, 08:35:33 PM
Upon closer inspection they are a little smaller - probably 175 but I could not see them on p.48 of the parts manual. I have two that look new, anybody want them? Need your shipping address. Thanks for the input.

- Bob
Title: Re: What's This Part?
Post by: moonpup on February 10, 2018, 09:24:23 PM
Not sure what the belong to and not even sure they're Bridgestone, but they're not 175 dampers.  Here's what they look like.....
Title: Re: What's This Part?
Post by: mqtsteve on February 11, 2018, 06:21:41 AM
Moonpup,
Those looks like the BS90 dampers for the cushdrive rear hub (p/n 7319-3111).  Steve
Title: Re: What's This Part?
Post by: OldSwartout on February 11, 2018, 08:03:56 AM
Not sure what the belong to and not even sure they're Bridgestone, but they're not 175 dampers.  Here's what they look like.....
Those are the 175 dampers prior to S/N 16M, after that, the rear drive was changed to 6 separate dampers bolted to the back of the sprocket. That carried through to the 200, of course.  The manuals don't show the revised configuration, but the part numbers are listed in the parts catalog.
Title: Re: What's This Part?
Post by: moonpup on February 11, 2018, 11:00:33 AM
Not sure what the belong to and not even sure they're Bridgestone, but they're not 175 dampers.  Here's what they look like.....
Those are the 175 dampers prior to S/N 16M, after that, the rear drive was changed to 6 separate dampers bolted to the back of the sprocket. That carried through to the 200, of course.  The manuals don't show the revised configuration, but the part numbers are listed in the parts catalog.

Thanks Karl, I keep forgetting that the 175's had a bunch of "before/after" stuff.  :-[

Anyway, I found this rear sprocket on ebay for the SR 175's and it has the groove in the back. Maybe that's what these dampers are for?

https://www.ebay.com/itm/NOS-Bridgestone-Motorcycle-175-SR-RACER-Rear-Sprocket/252253592349?epid=1611835581&hash=item3abb7c5b1d:g:EvQAAMXQJRhRapnB&vxp=mtr
Title: Re: What's This Part?
Post by: davis on February 11, 2018, 01:21:01 PM
Good job, you guys nailed it!
Title: Re: What's This Part?
Post by: slawsonb on February 12, 2018, 11:46:34 AM
BS archaeology! The most fun part of this obsession (imho)...
...bert