The Spares Company
Club Shop/Regalia
Parent Website
Contact Officials
Machine Registrar
Club Secretary
Membership Secretaries
MPH Editor and Forum Administrator.
Section Newsletters
Technical Databases
Photos
Home
What's new
Latest activity
Forums
New posts
What's new
New posts
Latest activity
Information
Bike Modifications
Machine Data Services
Manufacturers Manuals
Spare Parts Listings
Technical Diagrams
Whitakerpedia (Vincent Wiki)
The Club
MPH Material Archive
Flogger's Corner
Obituaries
VOC Sections
Local Sections
Local Section Newsletters
Miscellaneous
Club Assets
Club History
Club Rules
Machine Data Services
Meeting Documents
Miscellaneous
Essential Reading
Magazine/Newspaper Articles/Letters
Adverts and Sales Brochures
The Mighty Garage Videos
Bikes For Sale (Spares Company)
Log in
Register
What's new
New posts
Menu
Log in
Register
Install the app
Install
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Seat stay spacing
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Simon Dinsdale" data-source="post: 175133" data-attributes="member: 58"><p>Just measured 4 RFM's. One from 1951 measured 8.9". The others from 1949, 1951 & 1952 all measured 9" and these are all on built up bikes.</p><p>The seats on all 4 bikes were 8.9" to 9" as well.</p><p>If you run these out of alignment the seat will still pivot etc but with sideload on the damper drums in the seat stays they will then cause friction and eventually wear. Extra friction here though also has another consequence:</p><p></p><p>On a series C you don't actually want any friction there at all and I run the seat stays with PTFE linings and adjust the damper knobs so there is no side play but they still pivot with no friction and a drop of loctite nutlock on the damper knob threads stops the knobs undoing. You don't want any mechanical friction interfering with the rear hydraulic damper as they will fight against each other and in my opinion the factory should have eliminated the friction damper when they introduced the hydraulic damper. I suspect when owners say the rear suspension is very hard on a series C that they have tightened up the seat stay damper knobs really tight to stop them undoing themselves and falling off.</p><p>Basically the seat stay damper is a left over from series B's of which most didn't have a rear hydraulic damper.</p></blockquote><p></p>
[QUOTE="Simon Dinsdale, post: 175133, member: 58"] Just measured 4 RFM's. One from 1951 measured 8.9". The others from 1949, 1951 & 1952 all measured 9" and these are all on built up bikes. The seats on all 4 bikes were 8.9" to 9" as well. If you run these out of alignment the seat will still pivot etc but with sideload on the damper drums in the seat stays they will then cause friction and eventually wear. Extra friction here though also has another consequence: On a series C you don't actually want any friction there at all and I run the seat stays with PTFE linings and adjust the damper knobs so there is no side play but they still pivot with no friction and a drop of loctite nutlock on the damper knob threads stops the knobs undoing. You don't want any mechanical friction interfering with the rear hydraulic damper as they will fight against each other and in my opinion the factory should have eliminated the friction damper when they introduced the hydraulic damper. I suspect when owners say the rear suspension is very hard on a series C that they have tightened up the seat stay damper knobs really tight to stop them undoing themselves and falling off. Basically the seat stay damper is a left over from series B's of which most didn't have a rear hydraulic damper. [/QUOTE]
Insert quotes…
Verification
What was Mr Irving's Christian Name?
Post reply
Home
Forums
Forums: Public Access
Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Seat stay spacing
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top